Erythema multiforme target lesion on the skin of an 83 year old female patient following an infection with a Mycolplasma sp. bacterium. Erythema multiforme is a skin disorder that starts with itchy spots, which then progress to circular weals. Sometimes the body's internal mucous membranes are affected. This condition can occur secondary to infection or drugs. Some cases occur for no obvious reason. Treatment involves identifying possible causes and using drugs to treat the inflammation.