Red Smooth Patches

Abstract

Differential diagnosis of red, generally, smooth patches depends on the onset and duration of the eruption. If acute and short-lived, then the patient is likely to have morbilliform drug eruption or exanthem (not addressed here); and if subacute to chronic, then dermatomyositis (DM), photosensitive rash of systemic lupus erythematosus (SLE), or photosensitive drug eruption, and rarely subacute cutaneous lupus erythematosus (SCLE). Histopathology is not very helpful.