Erythema multiforme
Classification and external resources
Erythema multiforme minor of the hands ( note is make of the blanching centers of the lesion )
ICD-10	L51.
ICD-9	695.1
DiseasesDB	4450
MedlinePlus	000851
eMedicine	derm/137
MeSH	D004892

Erythema multiforme is a skin condition of unknown etiology, possibly mediated by deposition of immune complex ( mostly IgM ) in the superficial microvasculature of the skin and oral mucous membrane that usually follows an antecedent infection or drug exposure. It is a common disorder, with peak incidence in the second and third decades of life.

[edit] Presentation

The condition varies from a mild, self-limited rash (E. multiforme minor)^[1] 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, pink-red blotches, symmetrically arranged and starting on the extremities. It often takes on the classical "target lesion" appearance,^[2] with a pink-red ring around a pale center. Resolution within 7-10 days is the norm.

Individuals with persistent (chronic) erythema multiforme often have a sore form at an injury site, eg. 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. One sore grew in this way for 7 months, involving 90% of the calf of the leg.

[edit] Causes

The most common predisposing infection is Herpes simplex, but bacterial infections (commonly Mycoplasma) and fungal diseases are also implicated. It has been shown that Herpes simplex virus eradication and even prophylaxis (with aciclovir) can prevent recurrent erythema multiforme eruption.^2[3]

Other causes include drug reactions, most commonly to sulfa drugs, phenytoin, barbiturates, penicillin, and allopurinol, or a host of internal ailments.

The human form of orf can also cause erythema multiforme.

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.

[edit] Treatment

Erythema multiforme is frequently self-limiting and requires no treatment. The appropriateness of glucocorticoid therapy can be uncertain, because it is difficult to determine if the course will be self-limiting.^[4]

Erythema multiforme reaction to an antibiotic   "Erythema multiforme major" ( Stevens-Johnson syndrome); which resembles "erythema multiforme"   Target lesion

[edit] See also

• Erythema multiforme major

[edit] References