Ringworm, also known as tinea capitis or tinea corporis, is a common, contagious fungal disease that affects over 3 million people in the US annually. It is caused by dermatophytes that infect the skin and scalp by feeding on keratin. Symptoms include hair loss, itchy skin, rashes, and scaling. Ringworm is usually self-diagnosable and does not require lab testing. Treatment involves antifungal creams or oral medications. Proper hygiene can also help prevent the spread of the disease.