Tinea, a fungal skin infection, is commonly known as ringworm—owing to its typical appearance as an oval- or circular-shaped red rash. It is caused by a fungus that can infect the skin, fingernails, toenails, and/or hair. There are no worms involved.
Ringworm can appear on different body parts—arms and legs, hands or feet, trunk, scalp, genitals or groin area, and the face. There are different types of ringworm—and treatments—depending on the body part affected. For instance, ringworm of the hands and feet is called athlete’s foot; ringworm of the groin or genital areas is called jock itch.
Ringworm can be contagious and spread from person to person, pet (especially puppies and kittens) to person, or surface to person. Because the fungus thrives in damp, warm areas, people can contract it while walking barefoot on a locker room floor or using a towel contaminated with the fungus.
There is no national public health surveillance for common fungal infections, such as ringworm, so it is not possible to know exactly how many people contract ringworm each year in the United States. However, it is considered a common condition and can affect anyone at any age. Being infected with ringworm is completely normal and does not indicate an altered or depressed immune system.
The good news is that antifungal medication can cure ringworm. The type and length of treatment vary, depending on the location and severity of the infection.
What is ringworm?
Ringworm is a fungal skin infection that causes redness, itching, and burning in the affected area(s). It is contagious and easily spreads in moist, hot areas where the fungus thrives.
When a person comes into contact with the fungus that causes ringworm, the part of their body that touched it may become infected. From there, the fungus multiplies and can spread easily, even to other body parts. For instance, a person with athlete’s foot may later develop jock itch if their bare foot touches their underwear while getting dressed.
What causes ringworm?
Different fungi, including trichophyton, microsporum, and epidermophyton, cause ringworm.
What are the symptoms of ringworm?
Although people with ringworm may have fingernail or toenail infections, the hallmark symptom of the condition is a rash with the following characteristics:
- It contains rounded, red rashes (which may appear gray or brown on darker skin)
- It is scaly and/or contains pus-filled bumps
- It grows in size slowly
- It causes itchiness and a burning sensation
- It may cause temporary hair loss, if present on the scalp or beard
What are the risk factors for ringworm?
People may be at risk for ringworm infection if they:
- Have contact with a person or animal with ringworm
- Touch or wear clothing/towels used by a person with ringworm
- Use or touch combs, brushes, or other hair accessories touched by a person with ringworm of the scalp
- Remain in damp or sweaty clothing for long periods of time
- Stand or walk barefoot in a locker room, through a pool area, or in a shared shower where the fungus is present
- Spend time in hot, humid weather
- Wear tight-fitting clothing
- Have diabetes or weakened immune systems
Disinfectants or bleach can be used to kill ringworm on surfaces. Washing clothes, towels, and sheets in hot water with detergent should kill ringworm, as well as stop its spread.
How is ringworm diagnosed?
Doctors can diagnose ringworm after hearing a patient’s medical history, performing a physical exam, and, sometimes, via diagnostic tests.
If you suspect you have ringworm, tell your doctor when you first noticed the rash and what symptoms you have experienced. It’s helpful to share details about activities that may have exposed you to ringworm, such as using public pools, sharing a friend’s workout towel, or caring for a child with ringworm.
During a physical exam, your doctor may diagnose ringworm simply by inspecting your rash. In some cases, the doctor may scrape some cells from the site of the rash or the area beneath an affected fingernail or toenail. The cells will later be examined under a microscope by your doctor or a pathologist to check for a fungal infection.
In rare cases, the doctor will use skin scrapings for a fungal culture, during which the cells are grown in a laboratory setting to identify the type of fungus present on the skin.
How is ringworm treated?
Over-the-counter (OTC) antifungal treatments are often all that is needed to eliminate many forms of ringworm, including jock itch and athlete’s foot. These products come in cream, lotion, gel, spray, and powder forms. The fungal infection should disappear within two to four weeks. It’s important to use the medication for the entire length of time listed on the product, even if the condition seems to have disappeared.
If OTC treatments don’t cure ringworm within the time listed on the package, your doctor may prescribe one of the following medications, depending on the body part affected:
It’s important to note that ringworm on the scalp, beard, or nails typically doesn’t respond to OTC treatment; this type of infection needs to be treated with prescription medication that must be taken orally each day for one to three months.
What is the outlook for people with ringworm?
OTC medications can generally treat many kinds of ringworm within two to four weeks; however, ringworm infections of the scalp, beard, or nails require oral medication that can take up to three months to treat.
The fungus that causes ringworm is contagious. Making lifestyle changes, such as wearing flip-flops on pool decks instead of walking barefoot, changing socks and underwear at least once each day, wearing socks with shoes, keeping your skin clean and dry, and washing your hands with soap after playing with or touching pets, may help lower the risk of getting ringworm again.
This article was medically reviewed by Yale Medicine dermatologist Jeff Gelhausen, MD, PhD.