History:

This man presented with asymptomatic well-defined patches over his axillae, groins, and neck. They had been there for nearly a year without causing any symptoms.

Scrapings revealed no fungal elements and biochemical tests detected diabetes.

Erythrasma is caused by Corynebacterium minutissimum which show coral red fluorescence under Wood's lamp.Mostly found in diabetes, it is asymptomatic and responds to topical and oral antibiotics, particularly erythromycin.