Annular Lesions of the Skin: Diagnosis and Management Part II

Annular lesions represent a unique macro-morphologic pattern in various skin disorders that may be found in pityriasis rotunda, elastosis perforans serpiginosa, subacute nodular migratory panniculitis, keratolysis exfoliativa, neutrophilic eccrine hidradenitis, hemophagocytic lymphohistiocytosis, and intentionally induced annular lesions. This group is highly heterogenous and variable in clinical presentation. While some are benign self-limiting disorders like pityriasis rotunda, others follow a chronic course or have a potential of being life-threatening such as hemophagocytic lymphohistiocytosis. Epidemiology, pathogenesis, histopathology, clinical presentation and diagnosis, differential diagnosis and treatment are discussed.