Ringworm typically begins as a flat scaly area on the skin, which may be red and itchy. This patch develops a slightly raised border that expands outward — forming a roughly circular ring. The contours of the ring may be quite irregular, resembling the wavy outline of a snake or a worm.

The interior of the ring may be clear, scaly or marked with a scattering of red bumps. In some people, several rings develop at the same time and may overlap.

Ringworm is a contagious fungal infection caused by mold-like parasites that live on the cells in the outer layer of your skin. It can be spread in the following ways:

• Human to human. Ringworm often spreads by direct, skin-to-skin contact with an infected person.
• Animal to human. You can contract ringworm by touching an animal with ringworm. Ringworm can spread while petting or grooming dogs or cats. It's also fairly common in cows.
• Object to human. Ringworm can spread by contact with objects or surfaces that an infected person or animal has recently touched or rubbed against, such as clothing, towels, bedding and linens, combs, and brushes.
• Soil to human. In rare cases, ringworm can be spread to humans by contact with infected soil. Infection would most likely occur only from prolonged contact with highly infected soil.

You're at higher risk of ringworm of the body if you:

• Live in a warm climate
• Have close contact with an infected person or animal
• Share clothing, bedding or towels with someone who has a fungal infection
• Participate in sports that feature skin-to-skin contact, such as wrestling
• Wear tight or restrictive clothing
• Have a weakened immune system

A fungal infection rarely spreads below the surface of the skin to cause serious illness. But people with weak immune systems, such as those with HIV/AIDS, may find it difficult to get rid of the infection.