The patches of erythrasma are initially pink, but progress quickly to become brown and scaly (as skin starts to shed), which are classically sharply demarcated. Erythrasmic patches are typically found in intertriginous areas (skin fold areas - e.g. armpit, groin, under breast). The slightly webbed spaces between toes (or other body region skin folds) can be involved, making it difficult to distinguish from various Tinea. The patient is commonly otherwise asymptomatic. The diagnosis can be made on the clinical picture alone. However, a simple side-room investigation with a Wood's lamp is additionally useful in diagnosing erythrasma. The ultraviolet light of a Wood's lamp causes the organism to fluoresce a coral red color, differentiating it from other bacterial infections and other skin conditions. (fungal infections will also be fluorescent)
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