The palms, soles, dorsum of hands, and extensor surfaces are most commonly affected.

Patients with Stevens–Johnson syndrome can develop conjunctivitis. Meticulous eye care with erythromycin ointment can prevent ocular adhesions.

Mucosal involvement may include erythema, edema, sloughing, blistering, ulceration, and necrosis. Mouth erosions are painful and may impede adequate nutrition.