What Is Ringworm?
Ringworm is a skin infection caused by dermatophytes, a type of fungus that lives on the dead outer layer of skin. Despite its name, there is no worm involved in the condition. It’s called “ringworm” because it can cause a circular rash shaped like a ring.
Ringworm is usually named based on where it affects the body:
What Are Symptoms of Ringworm?
Ringworm affects the skin along with the fingernails and toenails. The symptoms of ringworm appear between 4 to 14 days after coming into contact with the fungi that cause ringworm.
Symptoms of ringworm include:
- Ring-shaped rash
- Skin redness
- Scaly, cracked skin
- Hair loss
Symptoms of ringworm that are specific to a location on the body:
- Feet (tinea pedis or “athlete’s foot”):
- Red, swollen, peeling, itchy skin between the toes
- Soles and heels may also be affected
- Skin on the feet may blister in severe cases
- Groin (tinea cruris or “jock itch”):
- Scaly, itchy, red spots, usually on the inner sides of the skin folds of the thigh
- Scalp (tinea capitis):
- Scaly, itchy, red, circular bald spot
- Bald spot may expand in size and several spots could develop if the infection spreads
- Beard (tinea barbae):
- Scaly, itchy, red spots on the chin, cheeks, and upper neck
- Spots can become crusted over or filled with pus
- Affected hair may fall out
What Causes Ringworm?
Ringworm is most often caused by human dermatophytes, a type of fungus transmitted by direct contact with human ringworm sores. Ringworm may also be acquired from the soil or through exposure to animals (commonly household pets).
Risk factors for developing ringworm include:
- People with weakened immune systems (such as from HIV/AIDS, cancer, chemotherapy, diabetes, or certain medications)
- Use of public showers or locker rooms
- Athletes involved in contact sports
- Excessive sweating in tight shoes or clothing
- Close contact with affected animals including household pets
- Working with soil that has ringworm fungus
- Living in a warm, humid climate
- Close contact with a person who is infected
- Sharing bedding, towels, or clothing with a person who is infected
Is Ringworm Contagious?
Ringworm is extremely contagious. It is spread from person to person by direct contact or by touching clothing, bedding, towels, or even an object that has come into contact with an infected person’s skin. It can also be acquired in public showers or locker rooms, through soil that has ringworm fungus, and through animals such as household pets that have the ringworm fungus.
Ringworm is contagious until sores have healed completely.
How Is Ringworm Diagnosed?
Ringworm is often diagnosed with a physical examination of the affected skin. Tests that may be used to diagnose ringworm include:
- Skin scraping to be examined under a microscope or sent to a laboratory for a fungal culture
- Ultraviolet light may be used to diagnose two specific species: Microsporum canis and audouinii
What Is the Treatment for Ringworm?
Treatment for ringworm can vary depending on where on the body it occurs.
- Body and groin: tinea corporis and cruris (jock itch) treatment includes:
- Over-the-counter antifungal products
- For tinea cruris, keep the groin area clean and dry and wear cotton underwear
- Extensive or recurrent infections may require systemic antifungal therapy
- Feet: tinea pedis (athlete's foot) treatment includes:
- Scalp: tinea capitis treatment includes:
- Treatment with systemic antifungal medication (topical antifungal products are ineffective in treating tinea capitis)
- Itraconazole and fluconazole are considered safe and effective, but are not FDA-approved for tinea capitis
- Selenium sulfide shampoos can be used as adjunctive therapy
How Do You Prevent Ringworm?
- Keep skin clean and dry
- Dry off completely after showering or bathing
- Athletes involved in close contact sports should shower immediately after practice and keep sports gear clean
- Athletes should not share sports gear with others
- Don’t go barefoot in locker rooms or public showers
- Wear loose shoes that allow air to circulate freely around the feet
- Keep fingernails and toenails clean and trimmed short
- Do not share clothing, towels, sheets, or personal items with an infected person
- Wash hands with soap and water after playing with pets
- If you suspect your pet has ringworm, take them to a veterinarian
- Vacuum areas the pet occupies
- Disinfect surfaces and thoroughly launder pet bedding