Erythrasma is a long-term skin infection caused by bacteria. It commonly occurs in skin folds. 

Erythrasma is caused by the bacteria Corynebacterium minutissimum.

Erythrasma is more common in warm climates. You are more likely to develop this condition if you are overweight or have diabetes.

The main symptoms are reddish-brown slightly scaly patches with sharp borders. They may itch slightly. The patches occur in moist areas such as the groin, armpit, and skin folds. The patches often look similar to other fungal infections, such as ringworm.

• Lab tests of scrapings from the skin patch
• Wood's lamp examination

Gently scrubbing the skin patches with antibacterial soap may help them go away. Your doctor may prescribe erythromycin gel that you put on the skin. If the condition is very bad, you may need to take this medicine in pill form. 

The condition should go away after treatment. 

Call your health care provider if you have symptoms of erythrasma.

You may be able to reduce the risk of erythrasma if you:

• Bathe or shower often
• Keep your skin dry
• Wear clean cloths that absorb moisture
• Avoid very hot or damp conditions
• Maintain a healthy body weight

Habif TP. Superficial and fungal infections. In: Habif TP, ed. Clinical Dermatology. 5th ed. St. Louis, Mo: Mosby Elsevier; 2009:chap 13.

Millett CR, Hapern AV, Reboli AC, et al. Bacterial Diseases. In: Bolognia JL, Jorizzo JL, Schaffer JV, et al, eds.Dermatology. 3rd ed. Philadelphia, Pa: Mosby Elsevier; 2012:chap 74.