Erythema Multiforme

Hypersensitivity Syndromes and Vasculitis

Erythema Multiforme is a common recurrent and acute inflammatory disease which presents with characteristic ‘target-shaped lesions’, erythematous macules and papules, as well as vesicles and papules. It is commonly associated with herpes simplex virus and upper respiratory tract infections, as well as with pneumonia. In addition, Erythema Multiforme is seen rarely with drugs, physical agents and pregnancy.

Target Lesions

These target-shaped lesions are believed to be the result of a CD8+ cytotoxic T cell immune response against keratinocytes expressing antigens from viruses. These lesions initially in a symmetric pattern suddenly and appear as red, round macules and papules that can burn or itch. The lesions are found on the palms/soles and dorsal aspects of the feet and hands and extensor aspects of the forearms and legs. Early lesions subsequently evolve into ‘target-lesions’ over a 2 day period. The lesions resolve over a 2 week period without scarring, however with some changes in pigmentation, such as hypo/hyperpigmentation of the skin.

Treatment

Most patients do not require treatment, as Erythema Multiforme is a self-limited disease. If there is widespread Erythema Multiforme, treatment with a systemic corticosteroid is effective, such as prednisone. Recurrent viral attacks from herpes should as be treated with acyclovir.