Ringworm is a fungal infection of the skin in humans and domestic animals such as sheep and cattle. Fungi are organisms that survive by eating plant or animal material. Those that cause parasitic infection (dermatophytes) feed on keratin, the material found in the outer layer of skin, hair, and nails. These fungi thrive best on skin that is warm and moist. This condition has been prevalent since before 1906, at which time ringworm was treated with compounds of mercury. Hairy areas of skin were considered too difficult to treat, so the scalp was treated with xrays and followed up with antiparasitic medication.
It is estimated that in current times, up to twenty percent of the population is infected by ringworm or one of the other dermatophytoses. It is especially common among people who play sports, wrestling in particular.
Misdiagnosis and treatment of ringworm with a topical steroid can result in tinea incognito, a condition where ringworm fungus will grow without typical features like a distinctive raised border.
Fungi thrive in moist, warm areas, such as locker rooms and swimming pools, and in skin folds. The fungi may be present without any symptoms.
Advice often given to prevent ringworm includes:
Antifungal treatments include topical agents such as miconazole or terbinafine applied twice daily until symptoms resolve (usually within two weeks), however if constantly touched it can leave a dark patch of skin where it had been. In more severe cases or where there is scalp ringworm, systemic treatment with oral medications may be given.