Due to overlap of clinical features including lesions of skin and mucous membranes and associations with drug exposure or infections, Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have traditionally been considered severe manifestations of erythema multiforme (EM) – and the term erythema multiforme major has been used as a synonym to SJS by some
However, more recent literature has suggested that SJS and TEN are distinct from EM based on some clinical and histopathologic characteristics
The spectrum of erythema multiforme is characterized by typical target lesions in a post-infectious period with relatively low morbidity (although the condition may be recurrent)
The spectrum of SJS/TEN is characterized by more diffuse blisters and purpuric macules, is more commonly associated with exposure to drugs, and has a high morbidity
In this concept, SJS and TEN represent gradations of severity of the same type of response
Description: Initially, flat atypical targets or purpuric maculae that may be described as painful or burning. Lesions coalesce to form blisters that may then progress to epidermal detachment.
Location: Symmetric, on upper trunk, or widespread. Reportedly, the lesions never involve the hairy portion of the scalp.
Other findings: Confluent erythema, facial edema, central face involvement, tongue swelling, palpable purpura, skin necrosis, epidermal detachment with lateral pressure (Nikolsky’s sign), mucous membrane erosions may all be seen, and all portend more serious condition
Pathophysiologic mechanisms not well elaborated. Current popular theory proffers that reactive drug metabolites may bind to carrier proteins on the membranes of epidermal cells and act as haptens, inducing primarily lymphocytic reaction, inflammatory cytokine release, cell death, and tissue necrosis.
Biopsy of denuded epidermis may be helpful if classic lesions not present demonstrates perivascular mononuclear infiltrate in papillary dermis, subepidermal blister formation, and full thickness epidermal necrosis
Supportive care (similar to burn patients): aggressive fluid repletion, strict hygiene precautions, surgical debridement and/or whirlpool therapy to remove necrotic epidermis, artificial tears, regular ophthalmologic exams
Treatment of secondary infections
Directed therapy: Corticosteroids controversial (mixed data). IVIG somewhat effective in small retrospective trial. Cyclophosphamide, cyclosporine, plasmapheresis, and GCSF have all been tried, but lack supporting data. Some authors advocate empiric use of acyclovir regardless of demonstration of HSV.