Erythema multiforme is a common skin disorder. It consists of
target-like circular lesions. They have a red center, pale ring,
and dark red outer ring. These lesions appear suddenly on the
legs, arms, palms, hands, feet, and inside the mouth. - Erythema
multiforme minor is the most frequent form. It is generally
mild. - Erythema multiforme major, while rare, can be life-
threatening. This severe form of the disorder usually causes
target lesions with painful blisters at their center. They tend
to appear on the trunk, eyes, inside the mouth, and genitals. It
is also called Stevens-Johnson syndrome. In some cases this
condition can be caused by a reaction to an infection or certain
medications. Often the cause is unknown. Erythema multiforme
minor is most commonly associated with: - Herpes simplex
virus—the same virus that causes cold sores Other triggers
connected with erythema multiforme major include: - Mycoplasma
infection (bacterial lung infection) - Cocaine use - History of
radiotherapy Certain medications