Multiple chemical sensitivity
Encyclopedia
Multiple chemical sensitivity (MCS) is a chronic medical condition
characterized by symptoms the affected person attributes to exposure to low levels of chemicals. Commonly suspected substances include smoke, pesticides, plastics, synthetic fabrics, scented products, petroleum products and paints. Symptom
s may be vague and non-specific, such as nausea
, fatigue, and headache
s.
MCS is a controversial diagnosis, and is not recognised as an organic, chemical-caused illness by the American Medical Association
. Blinded clinical trials have shown MCS patients react as often and as strongly to the exposure to the chemicals they say harm them as they do to placebo
s, including clean air. This has led some to believe MCS symptoms are due to odor hypersensitivity or are mainly psychological. Regardless of the etiology
, some people with severe symptoms are disabled as a result.
MCS has also been termed toxic injury (TI), chemical sensitivity (CS), chemical injury syndrome (CI), 20th century syndrome, environmental illness (EI), sick building syndrome
, idiopathic
environmental intolerance (IEI) and toxicant-induced loss of tolerance (TILT).
The National Institute of Environmental Health Sciences (a division of the NIH
) defines MCS as a "chronic, recurring disease caused by a person's inability to tolerate an environmental chemical or class of foreign chemicals". MCS has also been described as a group of "sensitivities to extraordinarily low levels of environmental chemicals" appearing "to develop de novo in some individuals following acute or chronic exposure to a wide variety of environmental agents including various pesticides, solvents, drugs, and air contaminants", including those found in sick buildings.
Environmental medicine specialists claim MCS causes negative health effects in multiple organ systems, and respiratory distress, seizures, cognitive dysfunction, heart arrhythmia, nausea, headache, and fatigue can result from exposure to levels of common chemicals that are normally deemed as safe.
, does not recognize multiple chemical sensitivity or environmental sensitivity as a valid diagnosis.
Because of the lack of scientific evidence, based on well-controlled clinical trials, that supports a cause-and-effect relationship between exposure to very low levels of chemicals and the myriad symptoms reported by clinical ecologists, MCS is not recognized as an established organic disease
by the American Academy of Allergy, Asthma, and Immunology
, the American Medical Association
(AMA), the California Medical Association
, the American College of Physicians
, or the International Society of Regulatory Toxicology and Pharmacology. In 1994, the AMA, American Lung Association
, US EPA
and US Consumer Product Safety Commission
published a booklet on indoor air pollution
that discusses MCS, among other issues. Although sometimes misrepresented as evidence these groups recognize MCS as a specific disease, the booklet states a pathogenesis of MCS has not been definitively proven. The booklet further states symptoms that have been self-diagnosed by a patient as related to MCS could actually be related to allergies or have a psychological basis. Finally, the booklet recommends physicians counsel individuals seeking medical assistance to alleviate their symptoms that they may benefit from consultation with specialists in these fields.
Ronald E. Gots, M.D., an environmental toxicologist and frequent defense consultant in toxic tort
litigation, describes MCS as "a label given to people who do not feel well for a variety of reasons and who share the common belief that chemical sensitivities are to blame. ... It has no consistent characteristics, no uniform cause, no objective or measurable features. It exists because a patient believes it does and a doctor validates that belief." In editorial in the Journal of Toxicology - Clinical Toxicology Gots wrote, "The phenomenon of multiple chemical sensitivities is a peculiar manifestation of our technophobic and chemophobic society. ... It may be the only ailment in existence in which the patient defines both the cause and the manifestations of his own condition."
In 1995, an Interagency Workgroup on Multiple Chemical Sensitivity was formed under the supervision of the Environmental Health Policy Committee within the United States Department of Health and Human Services
to examine the body of research that had been conducted on MCS to that date. The work group included representatives from the Centers for Disease Control and Prevention
, United States Environmental Protection Agency
, United States Department of Energy
, Agency for Toxic Substances and Disease Registry
, and the National Institutes of Health
. The Predecisional Draft document generated by the workgroup in 1998 recommended additional research in the basic epidemiology of MCS, the performance of case-comparison and challenge studies, and the development of a case definition for MCS. However, the workgroup also concluded it was unlikely MCS would receive extensive financial resources from federal agencies due to budgetary restraints and the allocation of funds to other, extensively overlapping syndromes with unknown etiology, such as chronic fatigue syndrome
, fibromyalgia
, and Gulf War syndrome
. The Environmental Health Policy Committee is currently inactive, and the workgroup document has not been finalized.
Commissioner John Callahan issued a court memorandum officially recognizing MCS "as a medically determinable impairment" on an agency-wide basis. With regard to the potential for exposure to chemicals in the workplace and MCS, the Occupational Safety and Health Administration (OSHA) has indicated MCS is highly controversial and there is insufficient scientific evidence to explain the relationship between the theorized causes of MCS and its symptoms. However, OSHA recommends “…an evaluation must be performed by a physician knowledgeable of the symptoms of this condition.”
A 1997 court decision held that MCS "is untested, speculative, and far from generally accepted in the medical or toxicological community," and thus cannot be used as the basis for disability claims. Furthermore, accommodations sought for MCS are sometimes denied as being unreasonable as a matter of law.
By far, the most common symptoms are vague complaints: feeling tired, "brain fog" (short-term memory problems, difficulty concentrating) and muscle pain. These complaints are common to a large number of medical conditions, from psychiatric conditions, such as major depressive disorder, to neurological conditions, such as orthostatic intolerance
, to high blood pressure, autoimmune diseases and cancer
.
A partial list of other symptoms patients have attributed to MCS include difficulty breathing
, pains in the throat, chest, or abdominal region, asthma
, skin irritation, contact dermatitis
, and hives or other forms of skin rash, headaches, neurological symptoms (nerve pain
, pins and needles
feelings, weakness
, trembling, restless leg syndrome, etc.), tendonitis
, seizure
s, visual disturbances (blurring, halo effect, inability to focus), extreme anxiety
, panic and/or anger, sleep disturbance, suppression of immune system, digestive difficulties, nausea
, indigestion/heartburn
, vomiting
, diarrhea
, joint pains, vertigo/dizziness, abnormally acute sense of smell, sensitivity to natural plant fragrance or natural pine terpene
s, insomnia, dry mouth, dry eyes, and an overactive bladder.
or panic disorder
. Other possible explanations include migraine
, anxiety disorder
, lupus
, postural orthostatic tachycardia syndrome
or other forms of orthostatic intolerance
, hay fever
and other allergies, hypercalcemia, hypothyroidism
, chronic fatigue syndrome
, or fibromyalgia
. Sufferers may also have a tendency to "catastrophically misinterpret benign physical symptoms" or simply a disturbingly acute sense of smell.
The distinction between physiological and psychological causes is often difficult to test, and it is particularly challenging for MCS because substances used to test for sensitivity can often be detected by scent. Odor cues make double blind studies of MCS patients difficult, and scents might provoke a psychosomatic response
. Research by Dr Mariko Saito et al. from the Department of Psychosomatic Medicine at the University of Tokyo in 2005 found patients only experienced symptoms when they themselves initiated the challenge tests. When they were given random prompts, there was no difference between MCS patients and controls in terms of physical and psychologic symptoms. Their conclusion was "MCS patients do not have either somatic or psychologic symptoms under chemical-free conditions, and symptoms may be provoked only when exposed to chemicals," although their results showed it was not the chemicals themselves that caused the symptoms.
A review of 37 provocation studies concluded "persons with MCS do react to chemical challenges; however, these responses occur when they can discern differences between active and sham substances, suggesting that the mechanism of action is not specific to the chemical itself and might be related to expectations and prior beliefs".
An alternative psychological cause has been suggested by a recent case-control study in which MCS was associated with a personality trait called absorption, in which individuals are predisposed to becoming deeply immersed in sensory experiences, leading to self-altered states of consciousness (see Flow
). When 54 MCS sufferers were compared to 44 subjects with a somatoform disorder and 54 normal individuals, only those with MCS were related to increased absorption scores, leading the authors to suggest absorption contributes to MCS by making individuals more susceptible to harboring beliefs in MCS, and these beliefs are reinforced by conditioning.
The cause and existence of MCS are disputed. In particular, doctors disagree about whether symptoms are physiologically or psychologically generated, or both. United States courts and several medical organizations reject MCS as a physiological disease. An approach called clinical ecology
attempts to treat the disease, but this work is controversial. Critics charge:
These claims are challenged, particularly (1) and (2), insofar as both definitions and physiological pathways have actually been proposed. The scientific community remains divided, however, with many proponents of the psychosomatic school rejecting physiological explanations outright.
on sensory nerve C-fibres, leading to the release of inflammatory mediators.
MCS people may have some neurological dysfunction in the odor-processing areas of the brain.
McKeown-Eyssen studied 203 MCS sufferers and 162 controls; blood tests revealed genetic differences relating to the body's detoxification processes were present more often in those with MCS than those without. The data showed five genetic polymorphisms have a statistically significant role in determining MCS prevalence. Each of these genes encode proteins that metabolize chemicals previously implicated in MCS, notably the organophosphate pesticides (PON1
and PON2 genes) and the organic solvents (CYP2D, NAT1 and NAT2 genes). People with a high expression of two specific genes (CYP2D6 and NAT2) were 18 times more likely to have MCS than those without. They concluded "a genetic predisposition for MCS may involve altered biotransformation of environmental chemicals." Haley found similar, confirmatory results with the PON1 gene in studies of the Gulf War syndrome veterans. A new study by Schnakenberg et al. (2006) confirmed the genetic variation previously found by McKeown-Eyssen and Haley. A total of 521 unrelated individuals participated in the study. Genetic variants of four genes were analyzed: NAT2, GSTM1, GSTT1, and GSTP1
. The researchers concluded the individuals who are NAT2 slow acetylators and those with homozygously deleted GSTM1 and GSTT1 genes are significantly more likely to develop chemical sensitivity. According to the study, the glutathione S-transferases act to inactivate chemicals, so people without these GSTM1 and GSTT1 genes are less able to metabolize environmental chemicals, because "glutathione S-transferases play an important role in the detoxification of chemicals". The deletion of another gene, the GSTP1
gene, leaves individuals more susceptible to developing these diseases, as lack of these genes means a loss of protection from oxidative stress.
A specific laboratory rat, the Flinders Sensitive line, has been bred by Dr. Overstreet to be sensitive to an organophosphate
, and displays "Increased sensitivity to cholinergic
agents [that] has also been observed in several human populations, including individuals suffering from chemical intolerance." In particular, Flinders Sensitive rats show increased responses to nicotine, alcohol, and other chemicals known to act on acetylcholine, dopamine, and serotonin receptors. However, these rats have not reacted abnormally to other chemicals thought to trigger MCS, such as perfume, in any known studies. Study of these rats may therefore provide useful clues about the mechanisms involved in some, but not all, forms of chemical intolerance in humans.
People who have stronger emotional states will react more strongly to a smell. The brain's emotional regions do not discriminate well between the different odors. That discrepancy between brain regions may relate to anxiety disorder
s. If the olfactory region does not distinguish a dangerous odor signal from a benign smell, the brain's fight-or-flight region
can overreact. Indeed, there has been some suggestion that the hypothalamic-pituitary-adrenal axis (the "stress axis") may be abnormal (blunted) in persons highly sensitive to chemicals, such as MCS, Addison's disease, chronic fatigue syndrome, and seasonal affective disorder
.
Food
Multiple food intolerance
s can be masked by a delayed reaction. These are not allergic reactions, and cannot be tested, only discovered by an elimination diet.
Substances with strong scents
In a review of a two-phase population study, respondents with MCS indicated cleaning agents (88.4%), pesticides (81.2%), perfumes (81.2%), vehicle exhaust (72.5%), the products used in barber shops and beauty salons (60.9%), new carpeting (53.6%), new furniture (39.1%), chlorine in drinking water (29.1%), and fresh ink (26.1%) were the products most often reported to trigger reactions in the respondents. They also indicated smoke from a fireplace, wood stove, or barbecue grill, and secondhand tobacco smoke were triggers for reactions.
Other reported chemical triggers include:
The "gold standard" procedure for identifying a person who has MCS is to test his or her response to the random introduction of chemicals the patient has self-identified as relevant, such as scented soaps or dryer sheets. This may be done in a carefully designed challenge booth to eliminate the possibility of contaminants in the room. Chemicals and controls, sometimes called prompts, are introduced in a random method, usually scent-masked. The test subject does not know when a prompt is being given. Objective and subjective responses are measured. Objective measures, such as the galvanic skin response
electrodermal response, indicate psychological arousal, such as fear, anxiety, or anger. Subjective responses include patient self-reports. A diagnosis of MCS can only be justified when the subject cannot consciously distinguish between chemicals and controls, and when responses are consistently present with exposure to chemicals and consistently absent when prompted by a control.
Investigators in Japan, Spain, Germany and the United States have used the Quick Environmental Exposure and Sensitivity Inventory (QEESI) as a self-screening questionnaire in their research on MCS. The QEESI is a shortened version of the Environmental Exposure and Sensitivity Inventory developed by Dr. Claudia S. Miller. The QEESI asks individuals to rank their responses to exposures from 0 to 10 in four scales: symptom severity, chemical intolerances, other intolerances, and life impact.
and anxiety disorder
s, and these conditions must be treated when present. The use of SSRI antidepressants
with a 53-year-old man with multiple chemical sensitivities showed a dramatic improvement, which suggests, as with the general population, a subgroup of MCS patients may have an atypical depression and should be evaluated for this condition.
Another study showed psychotherapy resulted in significant, long-term improvement in MCS symptoms, although there was no control group to which to compare results.
While patients typically resist the potentially stigmatizing diagnosis of an anxiety disorder, many MCS sufferers benefit strongly from lifestyle changes. A 2003 survey of 917 MCS patients revealed the two most effective treatments for MCS, in order of self-perceived harm/benefit ratio, were a chemical-free living space and chemical avoidance. Next came prayer
and meditation
, which presumably did no harm. By comparison, two-thirds of patients who had tried Zoloft thought it was harmful. Other treatments with perceived harm included other pharmaceutical drugs, provocative neutralization, hydrogen peroxide, Metagenics' UltraClear medical food, and microhydrin antioxidants. Overall, one or more antidepressants and anxiolytics were rated harmful by about half of survey respondents who had tried them, and as either harmless or helpful by the remaining respondents.
Other treatment modalities variably consist of the avoidance of known irritants, nutritional support to purge the body of its toxic load, sauna detoxification and autolymphycyte factor treatment.
Because many people eliminate whole categories of food in an effort to reduce symptoms, a complete review of the patient's diet may be needed to avoid nutritional deficiencies.
(1906–1995) was the first to describe "the chemical intolerance phenomenon" in the mid-20th century, calling it "unwitting addiction" and comparing it to drug and alcohol addiction, with the addiction cycle being transparent to the patient as a masked intolerance. When Randolph formulated his views, the term allergy was not connected with immunology
, as it has been since the late 1960s. It was then that non-immune-mediated hypersensitivities came to be called "intolerances", "idiopathic" or "idiosyncratic reactions" or "pseudoallergies". Randolph's theory was dismissed from the realm of allergology as the condition is not mediated by the humoral immune system.
are similar to those reported for MCS, including headache, fatigue, muscle stiffness, joint pain, inability to concentrate, sleep problems, and gastrointestinal issues.
A population-based, cross-sectional epidemiological study involving American veterans of the Gulf War, non-Gulf War veterans, and non-deployed reservists enlisted both during Gulf War era and outside the Gulf War era concluded the prevalence of MCS-type symptoms in Gulf War veterans was somewhat higher than in non-Gulf War veterans. After adjusting for potentially confounding factors (i.e., age, sex, and military training), there was a robust association between individuals with MCS-type symptoms and psychiatric treatment (either therapy or medication) before deployment and, therefore, before any possible deployment-connected chemical exposures.
The odds of reporting MCS or chronic multiple-symptom illness was 3.5 times greater for Gulf War veterans than non-Gulf veterans.
Gulf War veterans have an increased rate of multiple-symptom conditions compared to military personnel deployed to other conflicts, and although it is unexplained, Gulf War syndrome is not considered distinct from other medically unexplained syndromes observed in civilian populations, including MCS.
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
characterized by symptoms the affected person attributes to exposure to low levels of chemicals. Commonly suspected substances include smoke, pesticides, plastics, synthetic fabrics, scented products, petroleum products and paints. Symptom
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
s may be vague and non-specific, such as nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, fatigue, and headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...
s.
MCS is a controversial diagnosis, and is not recognised as an organic, chemical-caused illness by the American Medical Association
American Medical Association
The American Medical Association , founded in 1847 and incorporated in 1897, is the largest association of medical doctors and medical students in the United States.-Scope and operations:...
. Blinded clinical trials have shown MCS patients react as often and as strongly to the exposure to the chemicals they say harm them as they do to placebo
Placebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
s, including clean air. This has led some to believe MCS symptoms are due to odor hypersensitivity or are mainly psychological. Regardless of the etiology
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
, some people with severe symptoms are disabled as a result.
MCS has also been termed toxic injury (TI), chemical sensitivity (CS), chemical injury syndrome (CI), 20th century syndrome, environmental illness (EI), sick building syndrome
Sick building syndrome
Sick building syndrome is a combination of ailments associated with an individual's place of work or residence. A 1984 World Health Organization report into the syndrome suggested up to 30% of new and remodeled buildings worldwide may be linked to symptoms of SBS...
, idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
environmental intolerance (IEI) and toxicant-induced loss of tolerance (TILT).
Definition
Six consensus criteria were identified by researchers for the diagnosis and definition of MCS in 1989 (later edited in 1999):- Symptoms are reproducible with repeated (chemical) exposures.
- The condition has persisted for a significant period of time.
- Low levels of exposure (lower than previously or commonly tolerated) result in manifestations of the syndrome (i.e. increased sensitivity).
- The symptoms improve or resolve completely when the triggering chemicals are removed.
- Responses often occur to multiple chemically unrelated substances.
- Symptoms involve multiple-organ symptoms (runny nose, itchy eyes, headache, scratchy throat, ear ache, scalp pain, mental confusion or sleepiness, palpitations of the heart, upset stomach, nausea and/or diarrhea, abdominal cramping, aching joints).
The National Institute of Environmental Health Sciences (a division of the NIH
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
) defines MCS as a "chronic, recurring disease caused by a person's inability to tolerate an environmental chemical or class of foreign chemicals". MCS has also been described as a group of "sensitivities to extraordinarily low levels of environmental chemicals" appearing "to develop de novo in some individuals following acute or chronic exposure to a wide variety of environmental agents including various pesticides, solvents, drugs, and air contaminants", including those found in sick buildings.
Environmental medicine specialists claim MCS causes negative health effects in multiple organ systems, and respiratory distress, seizures, cognitive dysfunction, heart arrhythmia, nausea, headache, and fatigue can result from exposure to levels of common chemicals that are normally deemed as safe.
Lack of widespread recognition
The International Statistical Classification of Diseases and Related Health Problems (ICD), maintained by the World Health OrganizationWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
, does not recognize multiple chemical sensitivity or environmental sensitivity as a valid diagnosis.
Because of the lack of scientific evidence, based on well-controlled clinical trials, that supports a cause-and-effect relationship between exposure to very low levels of chemicals and the myriad symptoms reported by clinical ecologists, MCS is not recognized as an established organic disease
Organic disease
An organic disease is one which involves or affects physiology or bodily organs. A disease in which there is a physiological change to some tissue or organ of the body....
by the American Academy of Allergy, Asthma, and Immunology
American Academy of Allergy, Asthma, and Immunology
The American Academy of Allergy, Asthma & Immunology Founded in 1943, the AAAAI is a professional medical membership organization of nearly 6,500 allergist/immunologists and related professionals around the world with advanced training and experience in allergy, asthma and other immunologic diseases...
, the American Medical Association
American Medical Association
The American Medical Association , founded in 1847 and incorporated in 1897, is the largest association of medical doctors and medical students in the United States.-Scope and operations:...
(AMA), the California Medical Association
California Medical Association
The California Medical Association is a professional organization representing more than 35,000 physicians in the state of California. The organization was founded in 1856 and is a member of the American Medical Association.-Audio-Digest Foundation:...
, the American College of Physicians
American College of Physicians
The American College of Physicians is a national organization of doctors of internal medicine —physicians who specialize in the prevention, detection, and treatment of illnesses in adults. With 130,000 members, ACP is the largest medical-specialty organization and second-largest physician group in...
, or the International Society of Regulatory Toxicology and Pharmacology. In 1994, the AMA, American Lung Association
American Lung Association
The American Lung Association is a voluntary health organization whose mission is to save lives by improving lung health and preventing lung disease.-History:...
, US EPA
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
and US Consumer Product Safety Commission
Consumer Product Safety Commission
The United States Consumer Product Safety Commission is an independent agency of the United States government created in 1972 through the Consumer Product Safety Act to protect "against unreasonable risks of injuries associated with consumer products." The CPSC is an independent agency that does...
published a booklet on indoor air pollution
Indoor air quality
Indoor air quality is a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants....
that discusses MCS, among other issues. Although sometimes misrepresented as evidence these groups recognize MCS as a specific disease, the booklet states a pathogenesis of MCS has not been definitively proven. The booklet further states symptoms that have been self-diagnosed by a patient as related to MCS could actually be related to allergies or have a psychological basis. Finally, the booklet recommends physicians counsel individuals seeking medical assistance to alleviate their symptoms that they may benefit from consultation with specialists in these fields.
Ronald E. Gots, M.D., an environmental toxicologist and frequent defense consultant in toxic tort
Toxic tort
A toxic tort is a special type of personal injury lawsuit in which the plaintiff claims that exposure to a chemical caused the plaintiff's injury or disease.-Different types:...
litigation, describes MCS as "a label given to people who do not feel well for a variety of reasons and who share the common belief that chemical sensitivities are to blame. ... It has no consistent characteristics, no uniform cause, no objective or measurable features. It exists because a patient believes it does and a doctor validates that belief." In editorial in the Journal of Toxicology - Clinical Toxicology Gots wrote, "The phenomenon of multiple chemical sensitivities is a peculiar manifestation of our technophobic and chemophobic society. ... It may be the only ailment in existence in which the patient defines both the cause and the manifestations of his own condition."
In 1995, an Interagency Workgroup on Multiple Chemical Sensitivity was formed under the supervision of the Environmental Health Policy Committee within the United States Department of Health and Human Services
United States Department of Health and Human Services
The United States Department of Health and Human Services is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. Its motto is "Improving the health, safety, and well-being of America"...
to examine the body of research that had been conducted on MCS to that date. The work group included representatives from the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
, United States Environmental Protection Agency
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
, United States Department of Energy
United States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
, Agency for Toxic Substances and Disease Registry
Agency for Toxic Substances and Disease Registry
The Agency for Toxic Substances and Disease Registry is a federal public health agency within the United States Department of Health and Human Services. The agency focuses on minimizing human health risks associated with exposure to hazardous substances...
, and the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
. The Predecisional Draft document generated by the workgroup in 1998 recommended additional research in the basic epidemiology of MCS, the performance of case-comparison and challenge studies, and the development of a case definition for MCS. However, the workgroup also concluded it was unlikely MCS would receive extensive financial resources from federal agencies due to budgetary restraints and the allocation of funds to other, extensively overlapping syndromes with unknown etiology, such as chronic fatigue syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is the most common name used to designate a significantly debilitating medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially...
, fibromyalgia
Fibromyalgia
Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...
, and Gulf War syndrome
Gulf War syndrome
Gulf War syndrome or Gulf War illness describes a medical condition that affected veterans and civilians who were near conflicts during or downwind of chemical weapons depot demolition, after the 1991 Gulf War. A wide range of acute and chronic symptoms have included fatigue, musculoskeletal...
. The Environmental Health Policy Committee is currently inactive, and the workgroup document has not been finalized.
Limited recognition in some situations
In 1997, Social Security AdministrationSocial Security Administration
The United States Social Security Administration is an independent agency of the United States federal government that administers Social Security, a social insurance program consisting of retirement, disability, and survivors' benefits...
Commissioner John Callahan issued a court memorandum officially recognizing MCS "as a medically determinable impairment" on an agency-wide basis. With regard to the potential for exposure to chemicals in the workplace and MCS, the Occupational Safety and Health Administration (OSHA) has indicated MCS is highly controversial and there is insufficient scientific evidence to explain the relationship between the theorized causes of MCS and its symptoms. However, OSHA recommends “…an evaluation must be performed by a physician knowledgeable of the symptoms of this condition.”
A 1997 court decision held that MCS "is untested, speculative, and far from generally accepted in the medical or toxicological community," and thus cannot be used as the basis for disability claims. Furthermore, accommodations sought for MCS are sometimes denied as being unreasonable as a matter of law.
Clinical trials
Double-blind, placebo-controlled trials indicate people diagnosed with MCS do not reproducibly have symptoms when exposed to chemicals. In a 1993 study, MCS subjects could not discriminate between their chemical triggers and clean air when an olfactory masker was introduced that eliminated the ability to discriminate on the basis of odor. In a 2008 study, a variety of responses, including the subjective perception of being exposed to solvents, increases in blood pressure or heart rate, or increased symptom severity, were measured following the double-blind exposure to several solvents. People with an MCS diagnosis showed no differences in these parameters when they were exposed to clean air or to solvents at a concentration too low to smell. The trial did not support the hypothesis that MCS is directly related to the effects of chemical exposures. Since MCS sufferers seem to only have symptoms when they perceive exposure to chemicals, the syndrome is proposed to be a result of odor hypersensitivity in which individuals have an exaggerated response to scents, or psychological factors.Symptoms
Symptoms of MCS may be mild to disabling. Symptoms may be physical or psychological in nature and are essentially those that are disruptive to the individuals’ mental or physical wellness and that the individual attributes to exposure to a chemical or scent.By far, the most common symptoms are vague complaints: feeling tired, "brain fog" (short-term memory problems, difficulty concentrating) and muscle pain. These complaints are common to a large number of medical conditions, from psychiatric conditions, such as major depressive disorder, to neurological conditions, such as orthostatic intolerance
Orthostatic intolerance
Orthostatic intolerance is a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up....
, to high blood pressure, autoimmune diseases and cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
.
A partial list of other symptoms patients have attributed to MCS include difficulty breathing
Dyspnea
Dyspnea , shortness of breath , or air hunger, is the subjective symptom of breathlessness.It is a normal symptom of heavy exertion but becomes pathological if it occurs in unexpected situations...
, pains in the throat, chest, or abdominal region, asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, skin irritation, contact dermatitis
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...
, and hives or other forms of skin rash, headaches, neurological symptoms (nerve pain
Neuralgia
Neuralgia is pain in one or more nerves that occurs without stimulation of pain receptor cells. Neuralgia pain is produced by a change in neurological structure or function rather than by the excitation of pain receptors that causes nociceptive pain. Neuralgia falls into two categories: central...
, pins and needles
Pins and Needles
Pins and Needles is a musical revue with a book by Arthur Arent, Marc Blitzstein, Emmanuel Eisenberg, Charles Friedman, David Gregory, Joseph Schrank, Arnold B. Horwitt, John Latouche, and Harold Rome and music and lyrics by Rome...
feelings, weakness
Weakness
Weakness is a symptom represented, medically, by a number of different conditions, including: lack of muscle strength, malaise, dizziness, or fatigue. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a...
, trembling, restless leg syndrome, etc.), tendonitis
Tendonitis
Tendinitis , meaning inflammation of a tendon , is a type of tendinopathy often confused with the more common tendinosis, which has similar symptoms but requires different treatment...
, seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
s, visual disturbances (blurring, halo effect, inability to focus), extreme anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
, panic and/or anger, sleep disturbance, suppression of immune system, digestive difficulties, nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, indigestion/heartburn
Heartburn
Heartburn, also known as pyrosis or acid indigestion is a burning sensation in the chest, just behind the breastbone or in the epigastrium...
, vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, joint pains, vertigo/dizziness, abnormally acute sense of smell, sensitivity to natural plant fragrance or natural pine terpene
Terpene
Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeterium. They are often strong smelling and thus may have had a protective...
s, insomnia, dry mouth, dry eyes, and an overactive bladder.
Misdiagnosis
More than half of 56 people from one study about MCS instead had somatoform disorderSomatoform disorder
In psychology, a somatoform disorder is a mental disorder characterized by physical symptoms that suggest physical illness or injury - symptoms that cannot be explained fully by a general medical condition, direct effect of a substance, or attributable to another mental disorder . The symptoms that...
or panic disorder
Panic disorder
Panic disorder is an anxiety disorder characterized by recurring severe panic attacks. It may also include significant behavioral change lasting at least a month and of ongoing worry about the implications or concern about having other attacks. The latter are called anticipatory attacks...
. Other possible explanations include migraine
Migraine
Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
, anxiety disorder
Anxiety disorder
Anxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
, lupus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
, postural orthostatic tachycardia syndrome
Postural orthostatic tachycardia syndrome
Postural orthostatic tachycardia syndrome is a condition of dysautonomia, more specifically orthostatic intolerance, in which a change from the supine position to an upright position causes an abnormally large increase in heart rate, called tachycardia...
or other forms of orthostatic intolerance
Orthostatic intolerance
Orthostatic intolerance is a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up....
, hay fever
Hay Fever
Hay Fever is a comic play written by Noël Coward in 1924 and first produced in 1925 with Marie Tempest as the first Judith Bliss. Laura Hope Crews played the role in New York...
and other allergies, hypercalcemia, hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, chronic fatigue syndrome
Chronic fatigue syndrome
Chronic fatigue syndrome is the most common name used to designate a significantly debilitating medical disorder or group of disorders generally defined by persistent fatigue accompanied by other specific symptoms for a minimum of six months, not due to ongoing exertion, not substantially...
, or fibromyalgia
Fibromyalgia
Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...
. Sufferers may also have a tendency to "catastrophically misinterpret benign physical symptoms" or simply a disturbingly acute sense of smell.
Psychological
Several mechanisms for psychological etiology have been proposed, including theories based on stress, Pavlovian conditioning, or misdiagnoses of an underlying mental illness. Behavior exhibited by MCS sufferers may reflect broader sociological fears about industrial pollution.The distinction between physiological and psychological causes is often difficult to test, and it is particularly challenging for MCS because substances used to test for sensitivity can often be detected by scent. Odor cues make double blind studies of MCS patients difficult, and scents might provoke a psychosomatic response
Psychosomatic illness
Psychosomatic medicine is an interdisciplinary medical field studying the relationships of social, psychological, and behavioral factors on bodily processes and well-being in humans and animals...
. Research by Dr Mariko Saito et al. from the Department of Psychosomatic Medicine at the University of Tokyo in 2005 found patients only experienced symptoms when they themselves initiated the challenge tests. When they were given random prompts, there was no difference between MCS patients and controls in terms of physical and psychologic symptoms. Their conclusion was "MCS patients do not have either somatic or psychologic symptoms under chemical-free conditions, and symptoms may be provoked only when exposed to chemicals," although their results showed it was not the chemicals themselves that caused the symptoms.
A review of 37 provocation studies concluded "persons with MCS do react to chemical challenges; however, these responses occur when they can discern differences between active and sham substances, suggesting that the mechanism of action is not specific to the chemical itself and might be related to expectations and prior beliefs".
An alternative psychological cause has been suggested by a recent case-control study in which MCS was associated with a personality trait called absorption, in which individuals are predisposed to becoming deeply immersed in sensory experiences, leading to self-altered states of consciousness (see Flow
Flow (psychology)
Flow is the mental state of operation in which a person in an activity is fully immersed in a feeling of energized focus, full involvement, and success in the process of the activity. Proposed by Mihály Csíkszentmihályi, the positive psychology concept has been widely referenced across a variety of...
). When 54 MCS sufferers were compared to 44 subjects with a somatoform disorder and 54 normal individuals, only those with MCS were related to increased absorption scores, leading the authors to suggest absorption contributes to MCS by making individuals more susceptible to harboring beliefs in MCS, and these beliefs are reinforced by conditioning.
The cause and existence of MCS are disputed. In particular, doctors disagree about whether symptoms are physiologically or psychologically generated, or both. United States courts and several medical organizations reject MCS as a physiological disease. An approach called clinical ecology
Clinical ecology
Clinical ecology was the name given by proponents in the 1960s to a claim that exposure to low levels of certain chemical agents harm susceptible people, causing multiple chemical sensitivity and other disorders. Clinical ecologists are people that support and promote this offshoot of conventional...
attempts to treat the disease, but this work is controversial. Critics charge:
- MCS has never been clearly defined,
- no scientifically plausible mechanism has been proposed for it,
- no diagnostic tests have been substantiated, and
- not a single case has been scientifically validated.
These claims are challenged, particularly (1) and (2), insofar as both definitions and physiological pathways have actually been proposed. The scientific community remains divided, however, with many proponents of the psychosomatic school rejecting physiological explanations outright.
Neurological
One of the first studies on MCS (1993) focused on possible long-term potentiation in the hippocampi and neural sensitization as a central mechanism. Later studies examined the role of the inflammatory process, and found brain inflammation was correlated with symptoms of MCS. In 1999, Meggs proposed MCS is caused by low molecular weight-chemicals that bind to chemoreceptorsChemosensor
A chemoreceptor, also known as chemosensor, is a sensory receptor that transduces a chemical signal into an action potential. In more general terms, a chemosensor detects certain chemical stimuli in the environment.- Classes :...
on sensory nerve C-fibres, leading to the release of inflammatory mediators.
MCS people may have some neurological dysfunction in the odor-processing areas of the brain.
Genetic differences in metabolism
In 2004, McKeown-Eyssen and colleagues showed polymorphisms in the CYP2D6 allele responsible for variation in toxicant metabolism pathways may cause differences in susceptibility to MCS. Pall has suggested elevated nitric oxide and peroxynitrite (NO/ONOO-) as the etiology for MCS and several related conditions, including fibromyalgia, posttraumatic stress disorder, Gulf War syndrome, and chronic fatigue syndrome. This seems to be supported by a study by Reid et al. (2001) into the prevalence of MCS amongst British Gulf War syndrome sufferers. This study concluded veterans who had used personal organophosphate pesticides during the second Gulf War were 12 times more likely to develop MCS. Many observable and empirical, scientific facts can help identify MCS, including SPECT scans and chemical encephalopathy, vitamin deficiencies, mineral deficiencies, excess amino acid deficiency, and disturbed lipid and carbohydrate metabolism.McKeown-Eyssen studied 203 MCS sufferers and 162 controls; blood tests revealed genetic differences relating to the body's detoxification processes were present more often in those with MCS than those without. The data showed five genetic polymorphisms have a statistically significant role in determining MCS prevalence. Each of these genes encode proteins that metabolize chemicals previously implicated in MCS, notably the organophosphate pesticides (PON1
PON1
Paraoxonase 1 is a protein-coding gene. The protein encoded by this gene has esterase activity.-Function:PON1 is responsible for hydrolyising organophosphate pesticides and nerve gasses....
and PON2 genes) and the organic solvents (CYP2D, NAT1 and NAT2 genes). People with a high expression of two specific genes (CYP2D6 and NAT2) were 18 times more likely to have MCS than those without. They concluded "a genetic predisposition for MCS may involve altered biotransformation of environmental chemicals." Haley found similar, confirmatory results with the PON1 gene in studies of the Gulf War syndrome veterans. A new study by Schnakenberg et al. (2006) confirmed the genetic variation previously found by McKeown-Eyssen and Haley. A total of 521 unrelated individuals participated in the study. Genetic variants of four genes were analyzed: NAT2, GSTM1, GSTT1, and GSTP1
GSTP1
Glutathione S-transferase P is an enzyme that in humans is encoded by the GSTP1 gene.-Interactions:GSTP1 has been shown to interact with Fanconi anemia, complementation group C and MAPK8.-Further reading:...
. The researchers concluded the individuals who are NAT2 slow acetylators and those with homozygously deleted GSTM1 and GSTT1 genes are significantly more likely to develop chemical sensitivity. According to the study, the glutathione S-transferases act to inactivate chemicals, so people without these GSTM1 and GSTT1 genes are less able to metabolize environmental chemicals, because "glutathione S-transferases play an important role in the detoxification of chemicals". The deletion of another gene, the GSTP1
GSTP1
Glutathione S-transferase P is an enzyme that in humans is encoded by the GSTP1 gene.-Interactions:GSTP1 has been shown to interact with Fanconi anemia, complementation group C and MAPK8.-Further reading:...
gene, leaves individuals more susceptible to developing these diseases, as lack of these genes means a loss of protection from oxidative stress.
A specific laboratory rat, the Flinders Sensitive line, has been bred by Dr. Overstreet to be sensitive to an organophosphate
Organophosphate
An organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...
, and displays "Increased sensitivity to cholinergic
Cholinergic
The word choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation. Found in most animal tissues, choline is a primary component of the neurotransmitter acetylcholine and functions with inositol as a basic constituent of lecithin...
agents [that] has also been observed in several human populations, including individuals suffering from chemical intolerance." In particular, Flinders Sensitive rats show increased responses to nicotine, alcohol, and other chemicals known to act on acetylcholine, dopamine, and serotonin receptors. However, these rats have not reacted abnormally to other chemicals thought to trigger MCS, such as perfume, in any known studies. Study of these rats may therefore provide useful clues about the mechanisms involved in some, but not all, forms of chemical intolerance in humans.
Miscellaneous theories
Emotional stressesPeople who have stronger emotional states will react more strongly to a smell. The brain's emotional regions do not discriminate well between the different odors. That discrepancy between brain regions may relate to anxiety disorder
Anxiety disorder
Anxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
s. If the olfactory region does not distinguish a dangerous odor signal from a benign smell, the brain's fight-or-flight region
Fight-or-flight response
The fight-or-flight response was first described by Walter Bradford Cannon....
can overreact. Indeed, there has been some suggestion that the hypothalamic-pituitary-adrenal axis (the "stress axis") may be abnormal (blunted) in persons highly sensitive to chemicals, such as MCS, Addison's disease, chronic fatigue syndrome, and seasonal affective disorder
Seasonal affective disorder
Seasonal affective disorder , also known as winter depression, winter blues, summer depression, summer blues, or seasonal depression, is a mood disorder in which people who have normal mental health throughout most of the year experience depressive symptoms in the winter or summer, spring or autumn...
.
Chemical triggers
Multiple chemicals have been reported to trigger MCS symptoms. In addition to anything which is perfumed or scented, complaints are commonly formed about everyday items:Food
- TartrazineTartrazineTartrazine is a synthetic lemon yellow azo dye used as a food coloring...
(a.k.a FD&C Yellow #5 or E102), and other azo dyes (true allergyAllergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
must first be excluded) - CaffeineCaffeineCaffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
- Monosodium glutamateMonosodium glutamateMonosodium glutamate, also known as sodium glutamate or MSG, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids....
Multiple food intolerance
Food intolerance
Food intolerance or non-allergic food hypersensitivity is a term used widely for varied physiological responses associated with a particular food, or compound found in a range of foods....
s can be masked by a delayed reaction. These are not allergic reactions, and cannot be tested, only discovered by an elimination diet.
Substances with strong scents
In a review of a two-phase population study, respondents with MCS indicated cleaning agents (88.4%), pesticides (81.2%), perfumes (81.2%), vehicle exhaust (72.5%), the products used in barber shops and beauty salons (60.9%), new carpeting (53.6%), new furniture (39.1%), chlorine in drinking water (29.1%), and fresh ink (26.1%) were the products most often reported to trigger reactions in the respondents. They also indicated smoke from a fireplace, wood stove, or barbecue grill, and secondhand tobacco smoke were triggers for reactions.
Other reported chemical triggers include:
- Gasoline (petrol) or diesel fuel
- Petroleum-based products, including petroleum jelly, tar, or asphalt
- Pesticides, herbicides, fertilizers, and other agricultural chemicals
- Industrial cleaning chemicals, such as dry cleaning fluid
- Formaldehyde
- Glues, varnishes, polishes, paints, solvents, paint thinners, and volatile organic compoundVolatile organic compoundVolatile organic compounds are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and...
s (VOCs) - Bleach, fabric softenerFabric softenerFabric softener is used to prevent static cling and make fabric softer. It is available as a liquid, crystals and dryer sheets.- Varieties :...
s, wool-wash, and laundry detergents - Perfumes, lotion, aftershave lotion, nail polish, or skin care products
- Air fresheners, deodorizers and scented candles
- Shampoos, hairsprays and hair care products
- Dishwashing liquid and dishwasher detergent
- Marking pens, such as highlighters
Diagnosis
People who have developed symptoms of MCS have attributed a wide assortment of symptoms to chemical exposure, though symptoms are generally consistent for each individual. The first step in diagnosing a potential MCS sufferer is to identify and treat all other conditions which are present and which often explain the reported symptoms. For example, true allergy, thyroid disorders, orthostatic syndromes, anxiety, and depression need to be carefully evaluated and, if present, properly treated.The "gold standard" procedure for identifying a person who has MCS is to test his or her response to the random introduction of chemicals the patient has self-identified as relevant, such as scented soaps or dryer sheets. This may be done in a carefully designed challenge booth to eliminate the possibility of contaminants in the room. Chemicals and controls, sometimes called prompts, are introduced in a random method, usually scent-masked. The test subject does not know when a prompt is being given. Objective and subjective responses are measured. Objective measures, such as the galvanic skin response
Galvanic skin response
Skin conductance, also known as galvanic skin response , electrodermal response , psychogalvanic reflex , skin conductance response or skin conductance level , is a method of measuring the electrical conductance of the skin, which varies with its moisture level...
electrodermal response, indicate psychological arousal, such as fear, anxiety, or anger. Subjective responses include patient self-reports. A diagnosis of MCS can only be justified when the subject cannot consciously distinguish between chemicals and controls, and when responses are consistently present with exposure to chemicals and consistently absent when prompted by a control.
Investigators in Japan, Spain, Germany and the United States have used the Quick Environmental Exposure and Sensitivity Inventory (QEESI) as a self-screening questionnaire in their research on MCS. The QEESI is a shortened version of the Environmental Exposure and Sensitivity Inventory developed by Dr. Claudia S. Miller. The QEESI asks individuals to rank their responses to exposures from 0 to 10 in four scales: symptom severity, chemical intolerances, other intolerances, and life impact.
Treatment
In various studies, about one half of the patients who present with symptoms of MCS meet the criteria for depressiveClinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
and anxiety disorder
Anxiety disorder
Anxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
s, and these conditions must be treated when present. The use of SSRI antidepressants
Selective serotonin reuptake inhibitor
Selective serotonin re-uptake inhibitors or serotonin-specific reuptake inhibitor are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders. The efficacy of SSRIs is disputed...
with a 53-year-old man with multiple chemical sensitivities showed a dramatic improvement, which suggests, as with the general population, a subgroup of MCS patients may have an atypical depression and should be evaluated for this condition.
Another study showed psychotherapy resulted in significant, long-term improvement in MCS symptoms, although there was no control group to which to compare results.
While patients typically resist the potentially stigmatizing diagnosis of an anxiety disorder, many MCS sufferers benefit strongly from lifestyle changes. A 2003 survey of 917 MCS patients revealed the two most effective treatments for MCS, in order of self-perceived harm/benefit ratio, were a chemical-free living space and chemical avoidance. Next came prayer
Prayer
Prayer is a form of religious practice that seeks to activate a volitional rapport to a deity through deliberate practice. Prayer may be either individual or communal and take place in public or in private. It may involve the use of words or song. When language is used, prayer may take the form of...
and meditation
Meditation
Meditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....
, which presumably did no harm. By comparison, two-thirds of patients who had tried Zoloft thought it was harmful. Other treatments with perceived harm included other pharmaceutical drugs, provocative neutralization, hydrogen peroxide, Metagenics' UltraClear medical food, and microhydrin antioxidants. Overall, one or more antidepressants and anxiolytics were rated harmful by about half of survey respondents who had tried them, and as either harmless or helpful by the remaining respondents.
Other treatment modalities variably consist of the avoidance of known irritants, nutritional support to purge the body of its toxic load, sauna detoxification and autolymphycyte factor treatment.
Because many people eliminate whole categories of food in an effort to reduce symptoms, a complete review of the patient's diet may be needed to avoid nutritional deficiencies.
History
Allergist Theron G. RandolphTheron Randolph
Theron Randolph was a physician, allergist, and researcher from the United States. He studied food allergies, chemical allergies, and preventive care...
(1906–1995) was the first to describe "the chemical intolerance phenomenon" in the mid-20th century, calling it "unwitting addiction" and comparing it to drug and alcohol addiction, with the addiction cycle being transparent to the patient as a masked intolerance. When Randolph formulated his views, the term allergy was not connected with immunology
Immunology
Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders ; the...
, as it has been since the late 1960s. It was then that non-immune-mediated hypersensitivities came to be called "intolerances", "idiopathic" or "idiosyncratic reactions" or "pseudoallergies". Randolph's theory was dismissed from the realm of allergology as the condition is not mediated by the humoral immune system.
Epidemiology
As Magill and Seruda report:Most patients (85 to 90 percent) complaining of MCS syndrome are women. Most present between the ages of 30 and 50 years. Much additional basic descriptive and epidemiologic information is still unknown. The incidence and prevalence are unknown. The question of whether MCS is becoming more or less common is unanswered, as is the question of whether it is preventable. The natural history and biologic outcomes of MCS are unknown, and descriptions of MCS in primary care settings have not been reported. Selected patients from specialty settings comprise reports of the syndrome.
Relationship to Gulf War syndrome
Several clinical and epidemiological studies conducted in the United States and in the United Kingdom have investigated the occurrence of MCS in military personnel deployed to the Persian Gulf during the 1990s. Some of the health complaints and symptoms reported by veterans of the Gulf War attributed to Gulf War syndromeGulf War syndrome
Gulf War syndrome or Gulf War illness describes a medical condition that affected veterans and civilians who were near conflicts during or downwind of chemical weapons depot demolition, after the 1991 Gulf War. A wide range of acute and chronic symptoms have included fatigue, musculoskeletal...
are similar to those reported for MCS, including headache, fatigue, muscle stiffness, joint pain, inability to concentrate, sleep problems, and gastrointestinal issues.
A population-based, cross-sectional epidemiological study involving American veterans of the Gulf War, non-Gulf War veterans, and non-deployed reservists enlisted both during Gulf War era and outside the Gulf War era concluded the prevalence of MCS-type symptoms in Gulf War veterans was somewhat higher than in non-Gulf War veterans. After adjusting for potentially confounding factors (i.e., age, sex, and military training), there was a robust association between individuals with MCS-type symptoms and psychiatric treatment (either therapy or medication) before deployment and, therefore, before any possible deployment-connected chemical exposures.
The odds of reporting MCS or chronic multiple-symptom illness was 3.5 times greater for Gulf War veterans than non-Gulf veterans.
Gulf War veterans have an increased rate of multiple-symptom conditions compared to military personnel deployed to other conflicts, and although it is unexplained, Gulf War syndrome is not considered distinct from other medically unexplained syndromes observed in civilian populations, including MCS.
In media
- John StosselJohn StosselJohn F. Stossel is an American consumer reporter, investigative journalist, author and libertarian columnist. In October 2009 Stossel left his long time home on ABC News to join the Fox Business Channel and Fox News Channel, both owned and operated by News Corp...
's 1994 TV special The Blame Game, which chronicles cultural victimization and lack of responsibility in American society, includes a group of four employees of Tompkins County, New YorkTompkins County, New YorkTompkins County is a county located in the U.S. state of New York, and comprises the whole of the Ithaca metropolitan area. As of the 2010 census, the population was 101,564. The county seat is Ithaca, and the county is home to Cornell University, Ithaca College and Tompkins Cortland Community...
's Social Services Department who claimed to have been rendered disabled by MCS caused by the chemicals in their building. - In the TV series Northern ExposureNorthern ExposureNorthern Exposure is an American television series that ran on CBS from 1990 to 1995, with a total of 110 episodes.-Overview:The series was given a pair of consecutive Peabody Awards: in 1991–92 for the show's "depict[ion] in a comedic and often poetic way, [of] the cultural clash between a...
, the character Mike Monroe is portrayed as suffering from MCS. - The 1995 film "Safe," starring Julianne MooreJulianne MooreJulianne Moore is an American actress and a children's book author. Throughout her career, she has been nominated for four Oscars, six Golden Globes, three BAFTAs and nine Screen Actors Guild Awards....
and directed by Todd HaynesTodd HaynesTodd Haynes is an American independent film director and screenwriter. He is best known for his feature films Superstar: The Karen Carpenter Story, Poison, Velvet Goldmine, Safe, and the Academy Award-nominated Far from Heaven and I'm Not There.- Style and themes :The writes that "Haynes is...
, is about a woman who develops MCS. It was voted the best film of the 1990s in the 1999 Village Voice Film PollVillage Voice Film PollThe Village Voice Film Poll is an annual polling by The Village Voice film section of more than 100 major film critics for alternative media sources. Although the majority of the critics work for the alt-weeklies, a number are former Voice critics who now work for the mainstream media or have...
. - The 2008 work Tilt, by Italian writer Caterina Serra, reports and narrates the lives of many patients affected by MCS.
- Anne Lipscomb's 2009 memoir Poisoned by Pollution: An Unexpected Spiritual Journey details the author's struggles with MCS.
- In a 2009 episode of the TV series "BonesBones (TV series)Bones is an American crime drama television series that premiered on the Fox Network on September 13, 2005. The show is based on forensic anthropology and forensic archaeology, with each episode focusing on an FBI case file concerning the mystery behind human remains brought by FBI Special Agent...
," MCS patients are scammed and murdered. - Thilde Jensen NY Times Multimedia piece: Everything Makes Them Sick, September 17, 2011
External links
- Overview from the MCS support organization Chemical Injury Information Network
- "Seeking Modern Refuge From Modern Life in The New York Times (2006)
- Understanding and Accommodating People With MCS, Pamela Reed Gibson, Ph.D., James Madison University
- Multiple Chemical Sensitivity: a spurious diagnosis, Stephen BarrettStephen BarrettStephen Joel Barrett is a retired American psychiatrist, author, co-founder of the National Council Against Health Fraud , and the webmaster of Quackwatch. He runs a number of websites dealing with quackery and health fraud. He focuses on consumer protection, medical ethics, and scientific...
, MD. — A skeptical article hosted on QuackwatchQuackwatchQuackwatch is an American non-profit organization founded by Stephen Barrett with the stated aim being to "combat health-related frauds, myths, fads, fallacies, and misconduct" and with a primary focus on providing "quackery-related information that is difficult or impossible to get elsewhere."... - Position statement from the American Academy of Allergy, Asthma, and ImmunologyAmerican Academy of Allergy, Asthma, and ImmunologyThe American Academy of Allergy, Asthma & Immunology Founded in 1943, the AAAAI is a professional medical membership organization of nearly 6,500 allergist/immunologists and related professionals around the world with advanced training and experience in allergy, asthma and other immunologic diseases...