Based on the patient’s exam and history, we diagnosed erythrasma. Erythrasma is caused by the diphtheroid Corynebacterium minutissimum organism. The organism produces porphyrins, which result in the coral red fluorescence seen under a Wood’s lamp. Our patient barely fluoresced under a Wood’s lamp, but that can happen if a patient has recently washed the area. Erythrasma is characteristically found in the intertriginous areas—especially the axilla and the groin.
The treatment of choice is oral erythromycin 250 mg, 4 times a day, for 14 days. Cure rates are as high as 100%. The patient received a prescription for oral erythromycin and the erythrasma cleared completely.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Allred A, Usatine R. Erythrasma. In: Usatine R, Smith M, Mayeaux EJ, Chumley H, Tysinger J, eds. The Color Atlas of Family Medicine. New York, NY: McGraw-Hill; 2009:475-477.
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