Erythema Multiforme
Pronunciation: er-ih-THEE-mah mul-TIF-or-mee
An acute immune-mediated skin reaction characterised by target (iris) lesions, most commonly triggered by herpes simplex virus or drug hypersensitivity.
Full Definition
Erythema multiforme (EM) is a hypersensitivity reaction presenting with characteristic targetoid lesions—three concentric zones of color—distributed acrocentrically on the extremities and face. It exists on a spectrum: EM minor involves skin only, while EM major involves mucous membranes. Editors must carefully distinguish erythema multiforme from Stevens–Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), which are now considered separate entities despite historical overlap in older literature. 'Multiforme' is not hyphenated or capitalised separately. The abbreviation 'EM' must be expanded on first use.
Usage
Usage note: Do not conflate with Stevens–Johnson Syndrome; current classification treats them as distinct entities. Expand 'EM' on first use. 'Multiforme' is lowercase and unhyphenated when following 'erythema.'
In Context
- "Erythema multiforme developed 10 days after the onset of a labial herpes simplex recurrence." — Dermatology case report
- "The author labeled the condition 'SJS'; the editor queried whether the diagnosis met the criteria for erythema multiforme or true Stevens–Johnson Syndrome." — Editorial query