Clinical Features:

• Most common in children and young adults, with a slight male predominance
• Seasonal variation, with a peak in the spring and summer
• Self-limiting, but commonly recurs
• Presents as multiple, symmetrically distributed maculopapules with a predilection for the extensor surfaces of the extremities
• As the lesions progress, their centers become ischemic and bluish, resulting in the classic target lesions, and blisters sometimes form.
• Oral lesions are also frequently present.
• The lesions often heal leaving postinflammatory hyperpigmentation.
• Frequent recurrent episodes of erythema multiforme are associated with herpes simplex infection, which is the most common etiologic agent of the disease.
• Many other infectious agents, especially Mycoplasma, drugs and malignancies have also been implicated.
• An additional association, known as Rowell syndrome, is with discoid or systemic lupus erythematosus.

Histologic Features:

• Basal cell hydropic degeneration, which may be severe enough to result in the formation of subepidermal clefts or vesicles
• Apoptosis of keratinocytes, ranging from focal to diffuse epidermal involvement
• Marked superficial dermal lymphohistiocytic inflammation with lymphocytic exocytosis and satellite cell necrosis
• Intra- and intercellular epidermal edema, sometimes resulting in spongiotic vesicles

Cases associated with this book:

Erythema multiforme
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection