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At a glance

An acute mucocutaneous hypersensitivity reaction of variable severity characterized by symmetrical skin eruptions, with or without mucous membrane lesions. This remains a skin condition for which the cause is unknown. It is a type of erythema possibly mediated by deposition of IgM-bound complexes in the superficial microvasculature of the skin and oral mucous membrane (occasionally the eyes) that usually follows an infection or drug exposure. The clinical presentation tends to be fulminant in children. However, the peak incidence is in the second and third decades of life.


Erythème Polyforme (French appellation); EM; Dermatostomatitis, Erythema Multiforme Type; Erythema Multiforme Bullosum; Erythema Polymorphe Multiforme Type; Febrile Mucocutaneous Syndrome; Erythema Multiforme Herpes Iris Type.


The clinical presentation varies according to the lesions and its extent. It is named multiforme, ie, “multiform,” which is derived from multi + formis; and Target lesions. There are two types based on the severity of the symptoms and a third group involving more predominantly mucous membranes. The consensus classification consists of:

  • Erythema Multiforme Minor: Characterized by typical skin targets or raised, edematous papules distributed acrally.

  • Erythema Multiforme Major: Characterized by typical targets or raised, edematous papules distributed acrally with involvement of one or more mucous membranes. The presence of epidermal detachment is less than 10% of total body surface area (TBSA).

  • Stevens-Johnson Syndrome (SJS)/Toxic Epidermal Nec­rolysis (TEN): Characterized by widespread blisters predominant on the trunk and face, severe erythematous or pruritic macules and considerable mucous membrane erosions. The epidermal detachment is between 10 and 20% TBSA for the Stevens-Johnson Syndrome and greater than 30% for the Toxic Epidermal Necrolysis.


The terminology of the disorder is confusing, and the many names represent the spectrum of one disease that is part of mucocutaneous syndromes. Erythemas were first described in 1808 by Robert Willan (1757-1812), an English Physician, Founder of the Medical Specialty of Dermatology. He practiced medicine in London between 1783 and 1803 as a physician to the new Carey Street Public Dispensary. He was elected a Fellow of the Royal Society in 1809. Few years later, it was noticed that there were different clinical presentations of the same entity and this was first noted in 1860 by Ferdinan Ritter von Hebra (1816-1880), an Austrian physician and dermatologist known as the founder of the New Vienna School of Dermatology. Then, in 1916 Henri Jules Louis Marie Rendu (1844-1902), a French physician who was elected to the Académie Nationale de Médecine in 1897, described mucosal lesions with or without skin lesions, which were later named “ectodermosis erosiva pluriorificialis” by Nöel Armand Fiessinger (1881-1946), a French physician, in 1923. Meanwhile, in 1922 the American and English literature reported the association of skin and mucosal lesions with a systemic reaction, the Stevens-Johnson Syndrome. The common nature of all these conditions ...

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