19 - Figurate Erythemas

Abstract

While there are multiple cutaneous disorders that can present with annular lesions, from urticaria to granuloma annulare, this chapter focuses on the four classic figurate erythemas – erythema annulare centrifugum, erythema marginatum, erythema migrans, and erythema gyratum repens. In a figurate erythema, the lesions can assume an annular, arciform, or polycyclic configuration. The etiology or trigger for figurate erythemas varies from infections (e.g. erythema migrans due to Borrelia burgdorferi) to neoplasms (e.g. erythema gyratum repens due to lung carcinoma). However, oftentimes the underlying etiology of these reactive processes remains unknown or uncertain, especially in the case of erythema annulare centrifugum, also referred to as a gyrate erythema. Histologic examination, in addition to microbiologic and serologic evaluation, is often required to exclude specific etiologies prior to labeling the disorder as idiopathic. Treatment also varies from specific (e.g. doxycycline, amoxicillin) to nonspecific (e.g. topical corticosteroids).