Reactive Inflammatory Erythemas

Abstract

Multiple skin conditions can present with ring‐like or annular lesions for which a specific diagnosis can be made (e.g. tinea corporis, granuloma annulare, psoriasis or annular sarcoidosis). This chapter describes a group of conditions that do not necessarily lead to a specific underlying diagnosis and may pose diagnostic and therapeutic problems. It includes erythema multiforme, annular erythema of infancy, necrolytic migratory erythema (NME), erythema annulare centrifugum (EAC), erythema gyratum repens and erythema marginatum. EAC and subacute cutaneous lupus will be covered in separate chapters. Each eruption may have characteristic features and although diagnosis of erythema multiforme is often easy and there are a limited number of underlying causes, the diagnosis of NME may take time in view of the different manifestations of the disease. Physicians should be alert to the subtle eruption of erythema marginatum and the importance of diagnosing rheumatic fever. These cutaneous signs therefore present a challenge with heterogenous diseases presenting with varying morphologies.