Erythema Multiforme on the Knees

Erythema multiforme on the knees. Erythema multiforme is just as varied in appearance as its name suggests. Often if occurs on the extensor surfaces of the extermities, as in this picture. The causes of EM are also varied. One of the most common ones is recurring herpesvirus infection; however, the cause frequently remains unidentified. Cockade lesions are seen here.

Picture: Raimo Suhonen