Erythrasma is infection of the top layers of the skin caused by the bacterium Corynebacterium minutissimum.
Erythrasma affects mostly adults, especially those with diabetes and those living in the tropics. Erythrasma often appears in areas where skin touches skin, such as the webs of the toes, and genital area—especially in men, where the thighs touch the scrotum. The armpits, skin folds under the breasts or on the abdomen, and the area between the vaginal opening and the anus (perineum) are prone to this infection, particularly among those with diabetes and among obese middle-aged women. The infection can produce irregularly shaped pink or brown patches that may later turn into fine scales. In some people, the infection spreads to the torso and anal area.
Although erythrasma may be confused with a fungal infection, doctors can easily diagnose erythrasma because skin infected with Corynebacterium glows coral-red under an ultraviolet light.
An antibiotic given by mouth, such as erythromycin or tetracycline, can eliminate the infection. Antibacterial soaps, such as chlorhexidine, may also help. Topical drugs such as erythromycin and clindamycin are also effective. Antifungal creams such as miconazole may be helpful if yeast or fungus is present in the affected areas as well. Erythrasma may recur, necessitating a second treatment.
Last full review/revision October 2007 by A. Damian Dhar, MD, JD