Ringworm is an infection on the skin, hair, or nails caused by a fungus; it is not caused by a worm. Ringworm of the skin can spread quickly, is often itchy, and appears as a rash with patches that may be red, peeling, or scaly with blisterlike bumps on the edges that look like worms.

The medical term for many fungal infections is tinea, followed by a word that describes the location of infection. For example, tinea faciei is ringworm of the face.

Ringworm of the scalp or beard usually requires treatment with antifungal pills to completely destroy the fungi. Other kinds of ringworm often can be treated at home with medicines available without a prescription, such as antifungal creams, powders, and pills. But if the rash is widespread and severe, prescription antifungal pills may be needed.