Erythema multiforme
Encyclopedia
Erythema multiforme is a skin condition of unknown cause, possibly mediated by deposition of immune complex
(mostly IgM) in the superficial microvasculature of the skin and oral mucous membrane
that usually follows an infection or drug exposure. It is a common disorder, with peak incidence in the second and third decades of life.
) to a severe, life-threatening form known as erythema multiforme major
(or erythema multiforme majus) that also involves mucous membranes. This severe form may be related to Stevens–Johnson syndrome. The mild form is far more common than the severe form. Diagnosis is confirmed by biopsy.
The mild form usually presents with mildly itchy (but itching can be very severe), pink-red blotches, symmetrically arranged and starting on the extremities. It often takes on the classical "target lesion" appearance, with a pink-red ring around a pale center. Resolution within 7–10 days is the norm.
Individuals with persistent (chronic) erythema multiforme will often have a sore form at an injury site, e.g. a minor scratch or abrasion, within a week. Irritation or even pressure from clothing will cause the erythema sore to continue to expand along its margins for weeks or months, long after the original sore at the center heals.
, but bacterial infections (commonly Mycoplasma
) and fungal diseases are also implicated. Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption. The human form of orf
can also cause erythema multiforme.
Other causes include drug reactions, most commonly to sulfa drugs, phenytoin
, barbiturates, penicillin
, and allopurinol
, or a host of internal ailments.
Persistent (chronic) erythema multiforme has been linked to ingestion of benzoates in both natural and artificial forms, including benzoic acid, which occurs naturally in some fruit, and sodium benzoate, a common food preservative.
therapy can be uncertain, because it is difficult to determine if the course will be self-limiting.
Immune complex
An immune complex is formed from the integral binding of an antibody to a soluble antigen. The bound antigen acting as a specific epitope, bound to an antibody is referred to as a singular immune complex....
(mostly IgM) in the superficial microvasculature of the skin and oral mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
that usually follows an infection or drug exposure. It is a common disorder, with peak incidence in the second and third decades of life.
Presentation
The condition varies from a mild, self-limited rash (E. multiforme minorErythema multiforme minor
Erythema multiforme minor is a skin condition associated with a preceding herpetic infection, characterized by skin lesions that begin as sharply marginated, erythematous macules, which then become raised and develop a target-like appearance.Erythema multiforme minor is sometimes divided into...
) to a severe, life-threatening form known as erythema multiforme major
Erythema multiforme major
Erythema multiforme major is a term that may be used to refer to two conditions that constitute a spectrum of the same disease process:* Stevens–Johnson syndrome...
(or erythema multiforme majus) that also involves mucous membranes. This severe form may be related to Stevens–Johnson syndrome. The mild form is far more common than the severe form. Diagnosis is confirmed by biopsy.
The mild form usually presents with mildly itchy (but itching can be very severe), pink-red blotches, symmetrically arranged and starting on the extremities. It often takes on the classical "target lesion" appearance, with a pink-red ring around a pale center. Resolution within 7–10 days is the norm.
Individuals with persistent (chronic) erythema multiforme will often have a sore form at an injury site, e.g. a minor scratch or abrasion, within a week. Irritation or even pressure from clothing will cause the erythema sore to continue to expand along its margins for weeks or months, long after the original sore at the center heals.
Causes
The most common predisposing infection is Herpes simplexHerpes simplex
Herpes simplex is a viral disease caused by both Herpes simplex virus type 1 and type 2 . Infection with the herpes virus is categorized into one of several distinct disorders based on the site of infection. Oral herpes, the visible symptoms of which are colloquially called cold sores or fever...
, but bacterial infections (commonly Mycoplasma
Mycoplasma
Mycoplasma refers to a genus of bacteria that lack a cell wall. Without a cell wall, they are unaffected by many common antibiotics such as penicillin or other beta-lactam antibiotics that target cell wall synthesis. They can be parasitic or saprotrophic. Several species are pathogenic in humans,...
) and fungal diseases are also implicated. Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption. The human form of orf
Orf (animal disease)
Orf is an exanthemous disease caused by a parapox virus and occurring primarily in sheep and goats. It is also known as contagious pustular dermatitis, infectious labial dermatitis, ecthyma contagiosum, and sheep pox, thistle disease and scabby mouth...
can also cause erythema multiforme.
Other causes include drug reactions, most commonly to sulfa drugs, phenytoin
Phenytoin
Phenytoin sodium is a commonly used antiepileptic. Phenytoin acts to suppress the abnormal brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage-gated sodium channels...
, barbiturates, penicillin
Penicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....
, and allopurinol
Allopurinol
Allopurinol is a drug used primarily to treat hyperuricemia and its complications, including chronic gout.- Mechanism of action :...
, or a host of internal ailments.
Persistent (chronic) erythema multiforme has been linked to ingestion of benzoates in both natural and artificial forms, including benzoic acid, which occurs naturally in some fruit, and sodium benzoate, a common food preservative.
Treatment
Erythema multiforme is frequently self-limiting and requires no treatment. The appropriateness of glucocorticoidGlucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
therapy can be uncertain, because it is difficult to determine if the course will be self-limiting.
See also
- Erythema multiforme majorErythema multiforme majorErythema multiforme major is a term that may be used to refer to two conditions that constitute a spectrum of the same disease process:* Stevens–Johnson syndrome...
- Erythema multiforme minorErythema multiforme minorErythema multiforme minor is a skin condition associated with a preceding herpetic infection, characterized by skin lesions that begin as sharply marginated, erythematous macules, which then become raised and develop a target-like appearance.Erythema multiforme minor is sometimes divided into...
- Toxic epidermal necrolysisToxic epidermal necrolysisToxic epidermal necrolysis is a rare, life-threatening dermatological condition that is usually induced by a reaction to medications...
- Stevens–Johnson syndrome