Disease Fact Sheet Series:

What is ringworm?
Ringworm is an infection of the skin which is caused by several types of fungi. The scalp, feet, groin, fingernails or toenails can also be affected.

Who is susceptible to ringworm?
Anyone can get ringworm. Children are more susceptible to certain types of the ringworm fungi, while other types occur equally in all age groups. Ringworm involving the nails is more likely to occur following an injury to the nails.

What are the signs and symptoms of ringworm?
Ringworm of the body usually consists of a flat, roundish lesion, the edge of which may be dry and scaly or moist and crusted. As the lesion expands, the center portion often clears to a normal appearance. Ringworm of the scalp typically begins as a small pimple which expands with time, leaving scaly patches of temporary baldness. Infected hairs become brittle and break off easily. Occasionally, raised moist and draining lesions can occur. When finger/toe nails are affected, the nails become thickened, discolored, and brittle, or they may become chalky and disintegrate with time.

How is ringworm spread?
Ringworm can be transmitted indirectly by contact with objects such as hair brushes, combs, barber clippers, clothing that has contaminated hair on it, and from benches and shower stalls used by an infected persons. The fungi which cause ringworm can also be transmitted by direct contact with infected people or with infected pets and livestock.

How soon do symptoms occur?
Ringworm of the body appears approximately 4 to 10 days after the infection has been acquired, while ringworm of the scalp may take about 10 to 14 days to become apparent. The incubation period for ringworm of the nails is unclear.

How is ringworm diagnosed?
Physicians may diagnose the condition by the clinical appearance of the lesion, by culturing the fungus from the site, by a microscopic examination of a bit of material taken from the lesion, or by examining the site using a special ultraviolet lamp.

How is ringworm treated?
Antifungal ointment applied to the skin or oral antifungal drugs can be used to treat ringworm of the body. Ringworm of the scalp or nails require prolonged treatment with oral antifungal drugs.

Is a person who has already had ringworm immune to it?
Because ringworm is caused by several types of fungi, infection with one species of fungus will not necessarily make a person immune to future infections. Reinfection is uncommon for ringworm of the scalp, but is frequently seen in ringworm of the nails.

What can be done to prevent the spread of ringworm?
Infected individuals should not share towels, hats, or clothing with others. During the time when active lesions are present on exposed areas of the body, activities involving close physical contact with others should be limited. Towels, bed linen, and clothing used by infected persons should be thoroughly laundered. Young children who are infected should minimize close contact with other children until effectively treated.

In cases of ringworm of the scalp, daily shampooing will help remove loose hairs which may be infective. Persons with severe cases should wear caps to cover their hair. The caps should be disinfected after use by boiling. Hair brushes, combs, rollers, and other barber implements should not be shared and should be sterilized after use.

Common-use areas like locker room benches, floors, and shower stalls should routinely be kept clean and a fungicidal agent may be used on benches and floors.

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Last Revised: June 21, 2011