Histopathological spectrum of erythema multiforme

Area of Science:

• Dermatopathology
• Histology
• Immunopathology

Background:

• Erythema multiforme (EM) is an acute, immune-mediated mucocutaneous condition.
• Histological differentiation of EM from other vesiculobullous eruptions can be challenging.

Purpose of the Study:

• To histologically characterize lesions of erythema multiforme.
• To identify key features differentiating EM from other conditions.

Main Methods:

• Histological examination of 75 patient lesions.
• Analysis of epidermal and dermal inflammatory patterns.
• Quantification of specific cellular infiltrates, including eosinophils.

Main Results:

• Observed intercellular epidermal edema, subepidermal separation, and lymphohistiocytic infiltrate.
• Epidermal cell necrosis was present in variable percentages of lesions.
• Keratinocytic necrosis frequency varied across lesion types (macular, papular, bullous, iris).
• Eosinophils were noted in 60% of bullous and 28% of macular lesions.

Conclusions:

• EM exhibits a spectrum of histological presentations, from dermal disturbance to keratinocytic necrosis.
• Findings suggest a relationship between EM and toxic epidermal necrolysis.
• Characteristic histological features aid in differentiating EM from other eruptions.