Patient education: Ringworm (including athlete's foot and jock itch) (Beyond the Basics)

RINGWORM OVERVIEW — Despite its name, ringworm is not caused by a worm. Ringworm is actually an infection caused by a fungus. It is called ringworm because it can cause a ring-shaped, red, itchy rash on the skin. Ringworm is also called tinea.

There are several different types of ringworm infections, which are named from the body-part that is affected:

●Tinea capitis affects the top of the head, or scalp, and is found mostly in children.

●Tinea pedis affects the feet and is also called "athlete's foot."

●Tinea cruris affects the groin and is also called "jock itch."

●Tinea faciei affects the face.

●Tinea barbae affects the beard area.

●Tinea manuum affects the hands.

●Tinea corporis is the catch-all term for tinea infections on other body surfaces.

You can catch ringworm from someone else who is infected, or even from an infected dog or cat. You can also catch it from objects, such as a shower stall, locker room floor, or pool area that has the fungus. Plus, you can spread ringworm from one body part (such as your feet) to another (such as your groin or hand).

If you have ringworm, your health care provider may be able to diagnose it just by looking at your rash. In some cases, s/he will take some scrapings of the rash and look at it under a microscope to check for the fungus. Rarely, a health care provider may need to send scrapings from the rash for a fungal culture (a test used to identify fungus by growing it in a microbiology laboratory) or perform a skin biopsy, if necessary.

This article will discuss the symptoms and treatment of each type of ringworm infection. More detailed information about tinea is available by subscription (see "Dermatophyte (tinea) infections"). Fungal nail infections are also discussed separately. (See "Onychomycosis: Epidemiology, clinical features, and diagnosis".)

SCALP INFECTION (TINEA CAPITIS) — Tinea capitis usually causes a scaly, red rash that can lead to bald patches on the scalp (picture 1A-B). It usually affects children and is the most common cause of hair loss among children. It only rarely affects adults.

Scalp infections are treated with prescription antifungal medicines that you take by mouth. Topical treatments (lotions or creams) for tinea infections do not work on scalp infections. Treatment usually requires taking the medication once or twice per day for 2 to 12 weeks depending on the type of medication given and how well the infection responds to treatment.

To prevent tinea capitis from recurring, it's important to get rid of any combs, brushes, barrettes, or other hair care products that could be harboring the fungus. Family members should also be checked and treated, if necessary.

You can carry and spread the fungus but show no signs of infection; this person is called a carrier. In cases where the family pet is suspected to be the source of the infection, it's also important to have the animal treated.

If your child is being treated for tinea capitis with oral antifungal drugs, s/he can still go to school. There is no need to shave your child's head or cut their hair.

ATHLETE'S FOOT (TINEA PEDIS) — Tinea pedis causes the skin on the feet – often between the toes – to become itchy, red, cracked, tender, and scaly (picture 2A-B). Sometimes it also causes blisters to form. People who have tinea pedis often also have the infection on the palms of their hands, in their nails, or on their groin.

Unlike tinea capitis, tinea pedis responds to most topical antifungal treatments, many of which are available without a prescription. The cream/gel/lotion/powder is usually applied once or twice daily for four weeks (table 1). In severe or long-lasting cases, your health care provider may suggest an oral antifungal drug (which is available only by prescription).

To improve comfort and reduce the chances of repeat infection, it is a good idea to use antifungal foot powders, both on the feet and in the shoes, and to wear open shoes when feasible, at least while the feet heal. Wearing shoes in areas of high fungal sources, such as pools, communal showers, and locker rooms, may also help to prevent repeat infection.

JOCK ITCH (TINEA CRURIS) — Tinea cruris usually starts by causing a red, itchy rash in the groin, the crease where the leg meets the trunk. From there, it can spread onto the thighs and toward the buttocks or anus. It is more common in men than in women, and it often surfaces during warm or hot weather, after a bout of heavy sweating. The most common source of this infection is the person's own tinea pedis (athlete's foot).

Most cases of tinea cruris can be successfully treated with an antifungal cream/lotion/gel, some of which are available without a prescription. The treatment is usually applied once or twice per day for three to four weeks (table 1). It's essential, though, to treat tinea pedis (athlete's foot) at the same time; otherwise, the groin infection will likely recur. During treatment, avoid tight-fitting clothes.

BODY INFECTION (TINEA CORPORIS) — Tinea corporis is an infection that appears on a part of the body other than those listed above. Tinea corporis often develops when a tinea infection is transferred from another part of the body. It can also happen to parents who are caring for children with tinea capitis. It appears as a circular or oval scaly area. The outer edge is usually red and slightly raised while the center is flat and skin colored.

Tinea corporis usually responds to treatment with an antifungal cream/gel/lotion once or twice per day for one to two weeks (table 1). Athletes who have tinea corporis and who have close body contact (eg, wrestlers) may not be allowed to compete until the infection has cleared.

PREVENTING RINGWORM — To prevent ringworm and other skin infections:

●Do not share clothing, sports equipment, or towels with other people.

●When at the gym, local pool, or other public areas (including the shower), always wear slippers or sandals.

●Wash thoroughly with soap and shampoo after any sport involving skin-to-skin contact.

●Avoid tight-fitting clothing. Change your socks and underwear at least once a day.

●Keep your skin clean and dry. Always dry yourself completely after bathing.

●If you have athlete's foot, put your socks on before your underwear so that the infection does not spread to other parts of your body.

●Take your pet to the vet if it has patches of missing hair or a rash. That could be a sign of a tinea infection.

●If you or someone in your family has symptoms of ringworm, make sure s/he is treated right away. Otherwise, the infection may spread.

●If you have ringworm, make sure you use the treatment for the length of time suggested. It is important to complete the full treatment course.

WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Ringworm, athlete's foot, and jock itch (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

This topic currently has no corresponding Beyond the Basics content.

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Dermatophyte (tinea) infections
Onychomycosis: Epidemiology, clinical features, and diagnosis

The following organizations also provide reliable health information.

●National Library of Medicine

     (https://medlineplus.gov/tineainfections.html, available in Spanish)

●Center for Disease Control and Prevention

     (https://www.cdc.gov/fungal/diseases/ringworm/definition.html)

●KidsHealth

     (https://kidshealth.org/en/teens/ringworm.html)

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