Erythema multiforme

Lichenoid and interface dermatoses

The terms 'lichenoid' and 'interface' dermatitis are often used interchangeably to describe an inflammatory pattern characterized histologically by damage to the basal keratinocytes in the epidermis. The mechanism of cell damage of such cells is now best understood as apoptosis, or programmed cell death. This inflammatory pattern of dermatoses, is also accompanied frequently by a band of lymphocytes and histiocytes in the superficial dermis, that often obscures the dermal-epidermal junction, hence the term 'lichenoid'. A discussion of the more common lichenoid/interface dermatitides encountered in the routine clinical practice encompasses the following entities: lichen planus, lupus erythematosus, dermatomyositis, erythema multiforme, graft versus host disease, fixed drug reactions, and multiple others.

A nonscarring sublamina densa bullous drug eruption

The term bullous drug eruption connotes several heterogeneous diseases in which blisters occur as a complication of the administration of drugs. Blisters may occur in bullous erythema multiforme, fixed drug eruption, or severe dermatitis medicamentosa with blisters. The common denominator is thought to be a hypersensitivity reaction to a systemic medication. Nevertheless, little has been written about the blisters in these disorders, and neither common nor distinct pathogenic mechanisms have been proposed. We describe a patient who had a rapidly progressive bullous eruption that occurred within hours of receiving intravenous trimethoprim-sulfamethoxazole. Routine histologic study of lesional skin demonstrated subepidermal blisters. Transmission electron microscopy and immunomapping of various basement components revealed that the cleavage plane of the blister was well below the lamina densa. After healing of the blistering process, no scarring or milia formation was observed.

Head and neck manifestations of erythema multiforme in children

Erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis are related disorders of skin and mucous membranes, which are typically associated with antecedent medication use or infection. We review 108 cases of erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis from Texas Children's Hospital, Houston, Texas, from 1981 to 1991, and illustrate the characteristic skin and mucosal lesions. In addition, we describe in detail two unusual cases requiring intensive airway management. Head and neck manifestations were present in 4 of 79 patients (5%) with erythema multiforme and 26 of 28 patients (93%) with Stevens-Johnson syndrome. In Stevens-Johnson syndrome, mucosal involvement of the lip (93%), conjunctiva (82%), oral cavity (79%), and nose (36%) were most common. Antecedent medication use was identified in 59% of erythema multiforme patients and 68% of Stevens-Johnson syndrome patients. We note a striking increase in the number of cases in our series caused by cephalosporins. Fifty percent of Stevens-Johnson syndrome patients required supplemental hydration or alimentation because of the severity of the oral cavity involvement. The head and neck mucosal manifestations largely respond to local care, and the routine use of prophylactic antibiotics or systemic steroids is not recommended.