Fungal infection facts

What are fungal infections

Fungal infections are caused by a group of organisms that normally live on the skin, which can multiply to cause problems under certain conditions.

What causes fungal infections

Different types of fungus, such as yeast, normally live on the skin and cause no problems. Sometimes they grow in number and cause irritation, especially in areas of the body that are warm and moist, such as between the legs and under the breasts.

Wearing spandex, bike shorts, wet swimsuits, sweaty clothes, and multiple layers of clothing covering moist body areas can also encourage the growth of fungus. Fungal infections may also be worse in hot weather.

Fungal infections usually are NOT sexually transmitted.

Symptoms of fungal infections

• Red spots, itching, or white patches on the head of the penis, between the legs and on the buttocks.
• Itchy spots on the skin of the chest, back, trunk of the body and in the groin.
• Brown, tan, or red scaly patches that may have crusting or bumpy edges.
• Scaly patches between the legs and on the testicles.

How to treat fungal infections

• Get plenty of air to the rash.
• Try wearing boxer shorts instead of briefs.
• Don’t sleep in many layers of clothing.
• Dry your body off well after bathing.
• Topical medications (creams) called anti-fungals (miconazole, clotrimazole, etc) can be purchased at a drugstore without a prescription.

Choose these medicines in the cream form; they are more effective than powders. Use them twice a day and continue using them for a week after the rash has gone away. If they are not helping, return to the clinic for another exam.

This information is provided by San Francisco City Clinic.

Visit our homepage at sf.gov/cityclinic.

Information last revised October 2025