Anosmia is a lack of functioning
olfactionOlfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
, or in other words, an inability to perceive
odorAn odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
s. Anosmia may be either temporary or permanent. A related term,
hyposmiaHyposmia is a reduced ability to smell and to detect odours. A related condition is anosmia, in which no odours can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma...
, refers to a decreased ability to smell, while
hyperosmiaHyperosmia is an increased ability to smell - for example, being able to identify the perfume of the previous occupant of a chair. It is seen in patients with cluster headaches, migraines, and adrenal cortical insufficiency , although some people possess it naturally...
refers to an increased ability to smell. Some people may be anosmic for one particular odor. This is known as "specific anosmia". The absence of the sense of smell from birth is called Congenital Anosmia.
Anosmia is a lack of functioning
olfactionOlfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
, or in other words, an inability to perceive
odorAn odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...
s. Anosmia may be either temporary or permanent. A related term,
hyposmiaHyposmia is a reduced ability to smell and to detect odours. A related condition is anosmia, in which no odours can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma...
, refers to a decreased ability to smell, while
hyperosmiaHyperosmia is an increased ability to smell - for example, being able to identify the perfume of the previous occupant of a chair. It is seen in patients with cluster headaches, migraines, and adrenal cortical insufficiency , although some people possess it naturally...
refers to an increased ability to smell. Some people may be anosmic for one particular odor. This is known as "specific anosmia". The absence of the sense of smell from birth is called Congenital Anosmia.
Diagnosis
Anosmia can be diagnosed by doctors by using
acetylcysteine tests. Doctors will being will a detailed elicitation of history. Then the doctor will ask for any related injuries in relation to Anosmia which could include upper respiratory infections or head injury. Psychophysical Assessment of order and taste identification can be used to identity anosmia. A nervous system examination is performed to see if the cranial nerves are damaged. The diagnosis as well as the degree of impairment can now be tested much more efficiently and effectively than ever before thanks to "smell testing kits" that have been made available as well as screening tests which use materials that most clinics would readily have.
Presentation
Anosmia can have a number of harmful effects. Patients with sudden onset anosmia may find food less appetizing, though congenital anosmics rarely complain about this. Loss of smell can also be dangerous because it hinders the detection of
gas leakIn common usage, a gas leak refers to a leak of natural gas, from a pipe or other containment, into a living area or any other area where the gas should not be...
s, fire, and spoiled food. The common view of anosmia as trivial can make it more difficult for a patient to receive the same types of medical aid as someone who has lost other senses, such as hearing or sight.
Losing an established and sentimental
smell memoryOlfactory memory refers to the recollection of odours. Studies have found various characteristics of common memories of odour memory including persistence and high resistance to interference...
(e.g. the smell of grass, of the grandparents' attic, of a particular book, of loved ones, or of oneself) has been known to cause feelings of
depressionMajor 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...
.
Loss of olfaction may lead to the loss of
libidoLibido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
, though this usually does not apply to congenital anosmics.
Often people who have congenital anosmia report that they pretended to be able to smell as children because they thought that smelling was something that older/mature people could do, or did not understand the concept of smelling but did not want to appear different from others. When children get older, they often realize and report to their parents that they do not actually possess a sense of smell, often to the surprise of their parents.
Causes
A temporary loss of smell can be caused by a blocked
noseThe visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
or infection. In contrast, a permanent loss of smell may be caused by death of
olfactory receptor neuronAn olfactory receptor neuron , also called an olfactory sensory neuron , is a transduction cell within the olfactory system. J. Rospars, Dendritic integration in olfactory sensory neurons: a steady-state analysis of how the neuron structure and neuron environment influence the coding of odor...
s in the nose or by
brain injuryAn acquired brain injury is brain damage caused by events after birth, rather than as part of a genetic or congenital disorder such as fetal alcohol syndrome, perinatal illness or perinatal hypoxia. ABI can result in cognitive, physical, emotional, or behavioural impairments that lead to permanent...
in which there is damage to the
olfactory nerveThe olfactory nerve, or cranial nerve I, is the first of twelve cranial nerves. It is instrumental in the sense of smell. Derived from the embryonic nasal placode, the olfactory nerve is capable of regeneration.-Anatomy:...
or damage to brain areas that process smell (see
olfactory systemThe olfactory system is the sensory system used for olfaction, or the sense of smell. Most mammals and reptiles have two distinct parts to their olfactory system: a main olfactory system and an accessory olfactory system. The main olfactory system detects volatile, airborne substances, while the...
). The lack of the sense of smell at birth, usually due to genetic factors, is referred to as
congenital anosmia. Anosmia may very occasionally be an early sign of a degenerative brain disease such as
Parkinson's diseaseParkinson's disease is a degenerative disorder of the central nervous system...
and
Alzheimer's diseaseAlzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
. Another specific cause of permanent loss could be from damage to olfactory receptor neurons because of use of certain types of
nasal sprayNasal sprays come in a variety of forms. Medicated such as Astelin, Afrin and Nasonex and natural such as Sinusoothe and Sterimar. Although delivery methods vary, most nasal sprays function by instilling a fine mist into the nostril by action of a hand-operated pump mechanism.-Antihistamine nasal...
; i.e., those that cause vasoconstriction of the nasal microcirculation. To avoid such damage and the subsequent risk of loss of smell, vasoconstricting nasal sprays should be used only when absolutely necessary and then for only a short amount of time. Non-vasoconstricting sprays, such as those used to treat allergy related congestion, are safe to use for prescribed periods of time. Anosmia can also be caused by nasal polyps. These polyps are found in people with allergies, histories of sinusitis & family history. Individuals with
cystic fibrosisCystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine...
often develop nasal polyps.
Causes of anosmia include:
- Upper respiratory tract infection (e.g., sinusitis
Sinusitis is inflammation of the paranasal sinuses, which may be due to infection, allergy, or autoimmune issues. Most cases are due to a viral infection and resolve over the course of 10 days...
or the common coldThe common cold is a viral infectious disease of the upper respiratory system, caused primarily by rhinoviruses and coronaviruses. Common symptoms include a cough, sore throat, runny nose, and fever...
)
- Nasal polyps
- Idiopathic hypogonadotropic hypogonadism
- 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...
- Head trauma, damage to the ethmoid bone
The ethmoid bone is a bone in the skull that separates the nasal cavity from the brain. As such, it is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction. The ethmoid bone is one of the bones that makes up the orbit of the eye...
- Dementia with Lewy bodies
Dementia with Lewy bodies , also known under a variety of other names including Lewy body dementia, diffuse Lewy body disease, cortical Lewy body disease, and senile dementia of Lewy type, is a type of dementia closely allied to both Alzheimers and Parkinson's Diseases...
- Tumors of the frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
- Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
- Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
- Toxins (especially acrylate
The acrylate ion is the ion of acrylic acid.Acrylates are the salts and esters of acrylic acid. They are also known as propenoates ....
s, methacrylateMethacrylates are the salts or esters of methacrylic acid.Methacrylates contain methyl-vinyl groups, that is, two carbon atoms double bonded to each other, directly attached to the carbonyl carbon, and wherein the vinyl group is substituted with a non-terminal methyl group.Methacrylates are common...
s and cadmiumCadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
)
- Old age
- Kallmann syndrome
Kallmann syndrome is a genetic disorder marked by anosmia and hypogonadism - the decreased functioning of the glands that produce sex hormones. Abnormalities in various genes may cause a defect in the hypothalamus, causing a deficiency of gonadotropin-releasing hormone ; this in turn causes...
- Post-perfusion syndrome
- Laryngectomy
Laryngectomy is the removal of the larynx and separation of the airway from the mouth, nose and esophagus. The laryngectomee breathes through an opening in the neck, a stoma. This procedure is usually performed in cases of laryngeal cancer...
with permanent tracheostomy
- Esthesioneuroblastoma is an exceedingly rare cancerous tumor that originates in or near the olfactory nerve
The olfactory nerve, or cranial nerve I, is the first of twelve cranial nerves. It is instrumental in the sense of smell. Derived from the embryonic nasal placode, the olfactory nerve is capable of regeneration.-Anatomy:...
. Symptoms are anosmia (loss of sense of smell) often accompanied by chronic sinusitisSinusitis is inflammation of the paranasal sinuses, which may be due to infection, allergy, or autoimmune issues. Most cases are due to a viral infection and resolve over the course of 10 days...
.
- Intranasal
Insufflation is the practice of inhaling a substance. Insufflation has limited medical use, but is a common route of administration with many respiratory drugs used to treat conditions in the lungs and paranasal sinus .The technique is common for many recreational drugs and is also used for some...
drug useRecreational drug use is the use of a drug, usually psychoactive, with the intention of creating or enhancing recreational experience. Such use is controversial, however, often being considered to be also drug abuse, and it is often illegal...
- Samter's triad
Samter's triad is a medical condition consisting of asthma, aspirin sensitivity, and nasal/ethmoidal polyposis. It occurs in middle age and may not include any allergies.- Signs and symptoms :...
- Foster Kennedy syndrome
Foster Kennedy syndrome refers to a constellation of findings associated with tumors of the frontal lobe....
- Cadmium poisoning
Cadmium is an extremely toxic metal commonly found in industrial workplaces. Due to its low permissible exposure limit, overexposures may occur even in situations where trace quantities of cadmium are found. Cadmium is used extensively in electroplating, although the nature of the operation does...
- Smoking
Tobacco smoking is the practice where tobacco is burned and the resulting smoke is inhaled. The practice may have begun as early as 5000–3000 BCE. Tobacco was introduced to Eurasia in the late 16th century where it followed common trade routes...
- Neurotropic virus
A neurotropic virus is a virus which is capable of infecting nerve cells, or which does so preferentially. Such viruses thereby largely evade the usual immune response—which acts only within the blood system.- Terminology :...
- Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
- Pernicious anemia
Pernicious anemia is one of many types of the larger family of megaloblastic anemias...
- Zinc deficiency
Zinc deficiency is insufficient zinc to meet the needs of biological organisms. It can occur in both plants and animals. Zinc deficient soil is soil in which there is insufficient zinc to allow plants to grow normally.-Description:...
- Idiopathic intracranial hypertension
Idiopathic intracranial hypertension , sometimes called by the older names benign intracranial hypertension or pseudotumor cerebri , is a neurological disorder that is characterized by increased intracranial pressure in the absence of a tumor or other diseases...
- Suprasellar
meningiomaThe word meningioma was first used by Harvey Cushing in 1922 to describe a tumor originating from the meninges, the membranous layers surrounding the CNS ....
- Refsum's disease
Refsum disease, also known as classic or adult Refsum disease, heredopathia atactica polyneuritiformis, phytanic acid oxidase deficiency and phytanic acid storage disease, is an autosomal recessive neurological disease that results from the over-accumulation of phytanic acid in cells and tissues...
- Adrenergic agonists or withdrawal from alpha blocker
Alpha-1 blockers constitute a variety of drugs which block α1-adrenergic receptors in arteries and smooth muscles.-Pharmacology:...
s (vasoconstriction)
- Sarcoidosis
Sarcoidosis , also called sarcoid, Besnier-Boeck disease or Besnier-Boeck-Schaumann disease, is a disease in which abnormal collections of chronic inflammatory cells form as nodules in multiple organs. The cause of sarcoidosis is unknown...
- Zinc-based intranasal cold products
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
- Paget's disease of bone
Paget's disease is a chronic disorder that can result in enlarged and misshapen bones. The excessive breakdown and formation of bone tissue causes affected bone to weaken, resulting in pain, misshapen bones, fractures, and arthritis in the joints near the affected bones...
Zicam controversy
On June 16, 2009, the U.S.
Food and Drug AdministrationThe Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
sent a warning letter to Matrixx Initiatives, manufacturer of an over-the-counter nasal spray for the
common coldThe common cold is a viral infectious disease of the upper respiratory system, caused primarily by rhinoviruses and coronaviruses. Common symptoms include a cough, sore throat, runny nose, and fever...
,
ZicamZicam is a branded series of products marketed for cold and allergy relief whose original formulations included the element zinc. The Zicam name is derived from a combination of the words "zinc" and "ICAM-1" . It is marketed as an "unapproved homeopathic" product.Zicam was invented by Charles B...
. The FDA cited complaints that the product caused anosmia. The manufacturer strongly denies these allegations, but has recalled the product and has stopped selling it.
Associated conditions
- Dysosmia
Dysosmia, also known as olfactory dysfunction, is the impairment of olfactory stimuli processing leading to an altered sense of smell.These dysfunctions can present in a variety of ways, such as the stimuli not activating the olfactory bulb, some odors being interpreted as other odors, or...
- Kallmann syndrome
Kallmann syndrome is a genetic disorder marked by anosmia and hypogonadism - the decreased functioning of the glands that produce sex hormones. Abnormalities in various genes may cause a defect in the hypothalamus, causing a deficiency of gonadotropin-releasing hormone ; this in turn causes...
- Zinc deficiency
- Cadmium Poisoning
Cadmium is an extremely toxic metal commonly found in industrial workplaces. Due to its low permissible exposure limit, overexposures may occur even in situations where trace quantities of cadmium are found. Cadmium is used extensively in electroplating, although the nature of the operation does...
- Holoprosencephaly
Holoprosencephaly is a cephalic disorder in which the prosencephalon fails to develop into two hemispheres. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy...
- Primary amoebic meningoencephalitis
Primary amoebic meningoencephalitis is a disease of the central nervous system caused by infection from Naegleria fowleri.-Presentation:...
caused by Naegleria fowleriNaegleria fowleri is a free-living excavate form of protist typically found in warm bodies of fresh water, such as ponds, lakes, rivers, and hot springs. It is also found in soil, near warm-water discharges of industrial plants, and unchlorinated swimming pools in an amoeboid or temporary...
- Refsum disease
- CHARGE syndrome
CHARGE syndrome , is a syndrome caused by a genetic disorder. It was first described in 1979.In 1981, the term "CHARGE" came into use as an acronym for the set of unusual congenital features seen in a number of newborn children...
- Ageusia
Ageusia is the loss of taste functions of the tongue, particularly the inability to detect sweetness, sourness, bitterness, saltiness, and umami . It is sometimes confused with anosmia - a loss of the sense of smell...
Notable anosmic individuals
- Arjen Lucassen
- Selma Bouvier (Fictional Character)
- Dennis Brain
Dennis Brain was a British virtuoso horn player and was largely credited for popularizing the horn as a solo classical instrument with the post-war British public...
- Ben Cohen
- Dewey Cox (Fictional Character)
- Mary Baker Eddy
Mary Baker Eddy was the founder of Christian Science , a Protestant American system of religious thought and practice religion adopted by the Church of Christ, Scientist, and others...
- Michael Hutchence
Michael Kelland John Hutchence was an Australian musician and actor. He was the founding lead singer-songwriter of rock band :INXS from 1977 to his death in 1997, a period of twenty years. Hutchence was a member of short-lived pop rock group Max Q and recorded solo material which was released...
- Justin Hayward
Justin Hayward is an English musician, best known as singer, songwriter and guitarist in the rock band The Moody Blues.Hayward was born in Dean Street, Swindon, Wiltshire, England...
(for a period in the 1990s)
- Simon Katich
Simon Matthew Katich is an Australian cricketer. He is the captain of the New South Wales Blues, and also captained, up until the end of the 2007 season, Derbyshire County Cricket Club...
- Scott Kurtz (author of webcomic PvP)
- Bill Pullman
William James "Bill" Pullman is an American film, television, and stage actor. Pullman made his film debut in the supporting role of Earl Mott in the 1986 film Ruthless People. He has since gone on to star in other films, including Spaceballs, Independence Day, Lost Highway, Casper and Scary Movie 4...
- Harry Redknapp
Henry James "Harry" Redknapp is a former English footballer who has enjoyed a long career in football management starting in 1983 with Bournemouth. He is the current manager of Tottenham Hotspur....
- Simon Tatham
Simon Tatham is an English programmer known primarily for creating and maintaining PuTTY, a free software implementation of Telnet and SSH clients for Unix and Windows API platforms, along with an xterm terminal emulator...
- Benjamin Urrutia
Benjamin Urrutia is an author and scholar. With Guy Davenport, Urrutia edited The Logia of Yeshua, which collected what Urrutia and Davenport consider to be Jesus' authentic sayings from a variety of canonical and non-canonical sources...
- Stevie Wonder
Stevland Hardaway Morris , better known by his stage name Stevie Wonder, is an American singer-songwriter, multi-instrumentalist, record producer and activist...
- William Wordsworth
William Wordsworth was a major English Romantic poet who, with Samuel Taylor Coleridge, helped to launch the Romantic Age in English literature with the 1798 joint publication Lyrical Ballads....
- Kevin Schoettler
See also
- Hyperosmia
Hyperosmia is an increased ability to smell - for example, being able to identify the perfume of the previous occupant of a chair. It is seen in patients with cluster headaches, migraines, and adrenal cortical insufficiency , although some people possess it naturally...
- Hyposmia
Hyposmia is a reduced ability to smell and to detect odours. A related condition is anosmia, in which no odours can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma...
- Parosmia
Parosmia, also known as troposmia or cacosmia, is an olfactory dysfunction that is characterized by the inability of the brain to properly identify an odor’s “natural” smell....
- Richard Doty
Richard L. Doty, Ph.D., is a researcher in the field of olfactory functioning and dysfunction . He is the director of the University of Pennsylvania's Smell and Taste Center in Philadelphia, and Professor within the Department of Otorhinolaryngology: Head and Neck Surgery.- Training :Dr. Doty...
, Ph.D (researcher in the field of olfactory functioning and dysfunction)
External links