Erythema multiforme is an unusual hypersensitivity reaction of the skin which is often triggered by herpes simplex virus and medications including sulfa drugs. In milder forms, the outside of the arms and legs as well as the palms and soles may have small, rounded, red patches which appear like circles (bull's eye targets). A more severe form, called Stevens-Johnson syndrome, may sometimes develop where the rash may become more generalized with more severe involvement of the lips and mucous membranes of the mouth and genital region. Stevens-Johnson syndrome begins with flu-like symptoms, followed by a painful red or purplish rash that spreads and blisters, eventually causing the top layer of skin to die and shed. Stevens-Johnson syndrome is a medical emergency that usually requires hospitalization. Treatment focuses on eliminating the underlying cause, controlling symptoms and minimizing complications. Recovery after Steven-Johnson syndrome can take weeks to months, depending on the severity of your condition.