Common Causes
There are more than 40 species of fungi that can cause ringworm, according to the Centers for Disease Control and Prevention (CDC). These fungi are known as dermatophytes. Specific dermatophytes associated with the various types of ringworm, including athlete’s foot, jock itch, tinea capitis (a fungal infection of the scalp), and others include Trichophyton, Microsporum, and Epidermophyton.
Dermatophytes thrive in warm, moist areas of the body where they feed on dead keratin, skin cells on the epidermis and in nails and hair.
Ringworm can infect animals as well, and so when an infected pet—especially a new puppy or kitten—joins a household the human family members are at risk. If you adopt a pet, it’s vital to have it thoroughly examined by a veterinarian, but do look for signs of ringworm yourself: circular areas where there’s no fur or where the coat is brittle or has broken hairs and the skin is scaly, red, or crusty.
Dermatophyte fungi can thrive on inanimate surfaces as well. They produce spores that are shed into the infected child’s clothing, brushes or combs, and even into the air around the child. These spores can survive for months on objects.
Children are especially susceptible to ringworm and other skin rashes. People born with weak immune systems or who have compromised immune systems due to illness such as HIV/AIDs or certain medications, including corticosteroids or chemotherapy drugs, also have an increased risk of fungal infections.
Lifestyle Risk Factors
Health habits and other behaviors can put you at an increased risk of developing ringworm and other fungal infections. These include:
Not washing your hands frequently when around someone or something that might have been exposed to a fungusHaving damp skin for extended periods of time—for instance, not showering and drying off completely after sweating a lotMinor skin and nail injuriesClose contact with others who have ringworm, such as sharing a room or spending time in a classroom with someone who’s infected.
After sweating a lot, shower or bathe and dry off thoroughly. When practical, wear shoes that expose your feet to fresh air. Keep your nails clean and trimmed. Put on fresh socks and underwear every day.
Continuing to use the medication for as long as your doctor advises, even if the rash clears up quicklyWashing your hands thoroughly after applying medication—before you touch any other part of your bodyKeeping the affected area clean and dryIf you have multiple areas of infection, treating all of them at the same timeWashing towels, bedding, and clothing that may have been exposed to ringworm in hot, soapy water
