A
boil, also called a
furuncle, is a deep
folliculitisFolliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin with the exception of the palms of the hands and soles of the feet.- Causes :...
,
infectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
of the
hair follicleA hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
. It is always caused by infection by the bacterium
Staphylococcus aureusStaphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
, resulting in a painful swollen area on the
skinThe human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...
caused by an accumulation of
pusPus is a viscous exudate, typically whitish-yellow, yellow, or yellow-brown, formed at the site of inflammatory during infection. An accumulation of pus in an enclosed tissue space is known as an abscess, whereas a visible collection of pus within or beneath the epidermis is known as a pustule or...
and dead tissue. Individual boils clustered together are called
carbuncleA carbuncle is an abscess larger than a boil, usually with one or more openings draining pus onto the skin. It is usually caused by bacterial infection, most commonly Staphylococcus aureus. The infection is contagious and may spread to other areas of the body or other people...
s.
Staphylococcus is a
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of bacteria that is characterized by being round (coccus or spheroid shaped),
Gram-positiveGram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
, and found as either single cells, in pairs, or more frequently, in clusters that resemble a bunch of
grapeA grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
s. The genus name
Staphylococcus is derived from
GreekGreek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
terms "staphyle" and "kokkos" that mean "a bunch of grapes", which is how the bacteria often appears microscopically (after
Gram stainingGram staining is a method of differentiating bacterial species into two large groups ....
). In 1884,
GermanThe Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....
physicianA physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...
Ottomar RosenbachOttomar Ernst Felix Rosenbach was a German physician.Krappitz was a Silesian city where his father, Samuel Rosenbach, practised medicine. He received his education at the universities of Berlin and Breslau . His studies were interrupted by the Franco-Prussian war, in which he took an active part...
first described and named the bacteria. Two major divisions of the genus
Staphylococcus are separated by the bacteria's ability to produce
coagulaseCoagulase is a protein produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Coagulase negativity excludes S. aureus. That is to say, S...
, an
enzymeEnzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that can clot blood. Most human infections are caused by coagulase-positive
S. aureus strainsIn biology, a strain is a low-level taxonomic rank used in three related ways.-Microbiology and virology:A strain is a genetic variant or subtype of a micro-organism . For example, a "flu strain" is a certain biological form of the influenza or "flu" virus...
. Almost any organ system can be infected by
S. aureus.
Signs and symptoms
Boils are bumpy red,
pusPus is a viscous exudate, typically whitish-yellow, yellow, or yellow-brown, formed at the site of inflammatory during infection. An accumulation of pus in an enclosed tissue space is known as an abscess, whereas a visible collection of pus within or beneath the epidermis is known as a pustule or...
-filled lumps around a hair follicle that are
tender-Transportation:* Tender , a type of railroad car hauled immediately after the locomotive and used to carry fuel and water* Water tender, fire truck tanker-Boats/ships:* Buoy tender, used to maintain Aids to Navigation including buoys...
, warm, and very painful. They range from pea-sized to golf ball-sized. A yellow or white point at the center of the lump can be seen when the boil is ready to drain or discharge pus. In a severe infection, an individual may experience
feverFever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, swollen
lymph nodeA lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s, and fatigue. A recurring boil is called chronic furunculosis. Skin infections tend to be recurrent in many patients and often spread to other family members. Systemic factors that lower resistance commonly are detectable, including: diabetes, obesity, and hematologic disorders.
Causes
Usually, the cause is bacteria such as staphylococci that are present on the skin. Bacterial colonization begins in the
hair follicleA hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s and can cause local
cellulitisCellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,...
and inflammation. Additionally,
myiasisMyiasis is a general term for infection by parasitic fly larvae feeding on the host's necrotic or living tissue. Colloquialisms for myiasis include flystrike, blowfly strike, and fly-blown. In Greek, "myia" means fly....
caused by the
Tumbu flyCordylobia anthropophaga, the mango fly, tumbu fly, tumba fly, putzi fly or skin maggot fly is a species of blow-fly common in East and Central Africa. It is a parasite of large mammals during its larval stage .C...
in Africa usually presents with cutaneous furuncles.
Risk factorIn epidemiology, a risk factor is a variable associated with an increased risk of disease or infection. Sometimes, determinant is also used, being a variable associated with either increased or decreased risk.-Correlation vs causation:...
s for furunculosis include
bacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l carriage in the nostrils,
diabetes mellitusDiabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
,
obesityObesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
,
lymphoproliferativeLymphoproliferative disorders refer to several conditions in which lymphocytes are produced in excessive quantities. They typically occur in patients who have compromised immune systems...
neoplasms,
malnutritionMalnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
, and use of
immunosuppressive drugImmunosuppressive drugs or immunosuppressive agents are drugs that inhibit or prevent activity of the immune system. They are used in immunosuppressive therapy to:...
s. Patients with recurrent boils are as well more likely to have a positive family history, take antibiotics, and to have been hospitalized, anemic, or diabetic; they are also more likely to have associated skin diseases and multiple lesions.
Complications
The most common complications of boils are scarring and infection or abscess of the skin, spinal cord, brain, kidneys, or other organs. Infections may also spread to the bloodstream (
sepsisSepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
) and become life-threatening.
S. aureus strains first infect the skin and its structures (for example, sebaceous glands, hair follicles) or invades damaged skin (cuts, abrasions). Sometimes the infections are relatively limited (such as a
styeAn external stye or sty , also hordeolum , is an infection of the sebaceous glands of Zeis at the base of the eyelashes, or an infection of the apocrine sweat glands of Moll. External styes form on the outside of the lids and can be seen as small red bumps. Internal styes are infections of the...
, boil, furuncle, or carbuncle), but other times they may spread to other skin areas (causing cellulitis, folliculitis, or impetigo). Unfortunately, these bacteria can reach the bloodstream (bacteremia) and end up in many different body sites, causing infections (wound infections, abscesses,
osteomyelitisOsteomyelitis simply means an infection of the bone or bone marrow...
,
endocarditisEndocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...
,
pneumoniaPneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
) that may severely harm or kill the infected person.
S. aureus strains also produce enzymes and exotoxins (both secreted by staph) that likely cause or increase the severity of certain diseases. Such diseases include food poisoning, septic shock, toxic shock syndrome, and scalded skin syndrome. Almost any organ system can be infected by
S. aureus.
Treatment
In contrast to common belief, boils do not need to be drained in order to heal; in fact opening the affected skin area can cause further infections. In some instances, however, draining can be encouraged by application of a cloth soaked in warm salt water. Washing and covering the furuncle with antibiotic cream or antiseptic
tea tree oilTea tree oil, or melaleuca oil, is a pale yellow colour to nearly clear essential oil with a fresh camphoraceous odor. It is taken from the leaves of the Melaleuca alternifolia, which is native to the northeast coast of New South Wales, Australia...
and a bandage also promotes healing. Furuncles should never be squeezed or lanced without the oversight of a medical practitioner because it may spread the infection.
Furuncles at risk of leading to serious complications should be incised and drained by a medical practitioner. These include furuncles that are unusually large, last longer than two weeks, or are located in the middle of the face or near the spine.
AntibioticAn antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
therapy is advisable for large or recurrent boils or those that occur in sensitive areas (such as around or in the nostrils or in the ear).
Staphylococcus aureus has the ability to acquire antimicrobial resistance easily, making treatment difficult. Knowledge of the antimicrobial resistance of
S. aureus is important in the selection of antimicrobials for treatment. Poor personal hygiene being common, the role of nasal
S. aureus carrier may differ from communities with good hygienic practices.
Staphylococcus aureus re-infection may result from contact with infected family members, contaminated fomites, or from other extra-nasal sites. This raises a suggestion to treat household contacts and close contacts if recurrence persists, because it is likely that one or more contacts are asymptomatic carriers of
S. aureus. In addition to the increase in the cost of treatment in poor countries, the possibility of developing drug resistance must be considered. The most important independent predictor of recurrence is a positive family history. Boils are spread among individuals by touching or bursting a boil. Furunculosis is a common disease, particularly with deficient hygiene. A large number of
S. aureus organisms are frequently present on the sheets and underclothing of patients with furunculosis and may cause re-infection of patients and infection of other members of the family.
The role of iron deficiency anemia in recurrent furunculosis was demonstrated, all patients were free from recurrence during the six months follow-up period after iron supplementation.
A variety of host factors, such as abnormal neutrophil chemotaxis, deficient intra-cellular killing, and immuno-deficient states are of importance in a minority of patients with recurrent furunculosis. Health education about sound personal hygiene and correction of anemia should be mandatory in management of furunculosis.
It was found that recurrence was significantly associated with poor personal hygiene. A previous study reported that MRSA infection was significantly associated with poor personal hygiene. It was reported that frequent hand and body washing with water and antimicrobial soap solution decreases staphylococcus skin colonization. Previous use of antibiotics is associated with a high risk of recurrence. This may be due to the development of resistance to the antibiotics used. An associated skin disease favors recurrence. This may be attributed to the persistent colonization of abnormal skin with
S. aureus strains, such as is the case in patients with atopic dermatitis.
See also
- Hospital furunculosis
Hospital furunculosis is a cutaneous condition that can be epidemic in the hospital setting, characterized histopathologically by a deep abscess with both lymphocytes and neutrophils....
- Japanese spotted fever
Japanese spotted fever is a condition characterized by a rash that has early macules, and later, in some patients, petechiae.It is caused by Rickettsia japonica.- See also :* Flea-borne spotted fever...
- List of cutaneous conditions
External links