Erythema nodosum--diagnostic difficulties in the accident and emergency department.

Five patients presenting with erythema nodosum to an accident and emergency department are described. Initially they were misdiagnosed as cellulitis, infected insect bites, and minor trauma. Suspicious skin lesions or joint manifestations occurring either alone or especially if in combination should alert the wary clinician to the possibility of erythema nodosum and follow up in a few days may help to confirm the diagnosis.