Skin-nontumor / Clinical dermatology
Blistering disorders
Erythema multiforme

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 14 June 2016, last major update July 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Erythema multiforme [title] skin

Cite this page: Erythema multiforme. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumorerythemamultiforme.html. Accessed December 7th, 2016.
Definition / General
  • Acute, self limited, hypersensitivity reaction to infections (coccidioidomycosis, herpes simplex, histoplasmosis, leprosy, mycoplasma, typhoid), drugs (penicillin, phenylbutazone, phenytoin, salicylates, sulfa), carcinoma / lymphoma, or collagen vascular disorders
  • Affects skin (distal extremities, palms, soles) and mucous membranes with target lesions
  • Also sore throat and malaise
  • Any age
  • Commonly recurs, but rarely persists
Clinical Features
  • Variable (multiform) lesions ñ papules, macules, vesicles, bullae, target lesions
  • Commonly in mucous membranes; also elbows, knees, extensor surface of extremities
Clinical Images

Images hosted on PathOut servers:

Courtesy of Mark R. Wick, M.D.



Images hosted on other servers:

Target lesions

Micro Description
  • Subepidermal bullae with basement membrane in bullae roof due to dermal edema
  • Severe dermal inflammatory infiltrate (includes lymphocytes, histiocytes)
  • Eosinophils may be present, but neutrophils are sparse or absent
  • Overlying epidermis often demonstrates liquefactive necrosis and degeneration, dyskeratotic keratinocytes
  • May also have dermoepidermal bullae with basal lamina at floor of bullae
  • Variable epidermal spongiosis and eosinophils
  • No leukocytoclasis, no microabscesses, no festooning of dermal papillae

  • Note: erythema multiforme may have variable histologic changes from toxic epidermal necrolysis to dermal disturbances
Micro Images

Images hosted on PathOut servers:

Courtesy of Mark R. Wick, M.D.



Images hosted on other servers:

Various images

Positive Stains
  • Granular C3 and IgM at basement membrane and in vessels
Differential Diagnosis
Additional References