Ringworm (tinea)

What is ringworm?

Ringworm, also called tinea, is a skin infection caused by fungi, microscopic organisms that are similar to yeast and molds. It does not have any relation to worms, but is called "ringworm" because the infection can produce ring-shaped patches on the skin that have red, wormlike edges.

Although ringworm can affect almost any area of the body, it favors places that are warm, dark and moist, such as skin in the groin area, the spaces between the toes and the deep skin folds of obese people. People can catch ringworm in several different ways, including:

• direct skin-to-skin contact with an infected person
• playing with, or caring for, an infected pet or farm animal
• using an infected person's clothing, shoes or personal grooming items such as combs, brushes or towels
• sharing an infected child's toys, especially stuffed toys
• touching a contaminated surface — Some common high-risk surfaces include floors in bathrooms, showers and locker rooms; shower stalls; gym mats; and pool decks, especially at school or community pools. In general, any surface that is used by many different people can carry ringworm, especially if the surface is also wet or damp. Even contaminated carpets and couches can spread the infection.

Depending on its specific location, tinea may be known by a more common name, such as athlete's foot or jock itch. The various types of ringworm include:

• Ringworm of the scalp — This infection, also known as tinea capitis, causes patches of hair loss on the scalp. It is especially common among children aged 3 to 9, particularly children who live in crowded conditions in urban areas. Scalp ringworm spreads on contaminated combs, brushes, hats and pillows, and it may occur in epidemics in schools and day-care centers.
• Barber's itch (ringworm of the beard) — This fungal infection affects bearded areas of the face and neck in adult men.
• Ringworm of the body — Ringworm of the body, also known as tinea corporis, involves the non-hairy skin of the face, trunk, arms or legs. Of all types of ringworm, tinea corporis is the one that most often produces the classic, ring-shaped patches with wormlike borders. Ringworm of the body occurs in people of all ages and races, with women affected as often as men.
• Jock itch (ringworm of the groin) — This infection, also known as tinea cruris, typically causes itchy, scaly, red patches of skin on the groin area. It most often affects teenage and adult men, especially those who are obese, or who wear tight-fitting underwear. It is the most common type of tinea.
• Athlete's foot (ringworm of the foot) — Athlete's foot, also known as tinea pedis, is the second most common form of tinea. In some people, fungus also attacks the toenails. People often get athlete's foot by walking barefoot on contaminated floors, especially in gyms and locker rooms.

Doctors estimate that at least 20% of all people will develop tinea at some time during life. People who are more likely to get a fungal skin infection include:

• people who live in hot, humid climates
• athletes, especially swimmers
• children in day care
• people who work with animals
• obese people with deep, moist skin folds
• anyone whose immune defenses are weakened by illness (HIV, organ transplant, some cancers) or by medications.

Symptoms of ringworm

Symptoms of ringworm vary, depending on the site of the infection:

• Ringworm of the scalp — Symptoms can include a diffuse, itchy, scaling of the scalp that resembles dandruff; itchy, scaly, round patches of hair loss on the scalp; black-dot ringworm, in which stubs of broken hairs form a dotted pattern on the scalp; or kerion, a thick, nodular patch of inflamed skin that may ooze pus.
• Barber's itch — Symptoms often include kerion and crusted skin on bearded areas of the face and neck.
• Ringworm of the body — This infection causes itchy, red, scaly, round patches with a raised border. Individual patches may be large or small and may occur alone or in groups of three to four.
• Jock itch — Jock itch causes red, scaly patches that may itch or burn. These patches usually occur on the groin area and upper thigh, but not on the penis or scrotum.
• Athlete's foot — Athlete's foot produces areas of redness, scaling or cracked skin on the feet, especially between the toes. The affected skin may itch or burn, and the feet may have a strong odor.

Diagnosing ringworm

The best way for your doctor to diagnose any type of fungal infection in the skin is by scraping the area, and looking at the specimen under a microscope to see if it contains fungi. He or she also can determine if you have ringworm by the way it looks.

Although you may be able to diagnose yourself, you should call your doctor before you use over-the-counter treatment. Your doctor will ask you questions about your lifestyle, including whether you are athletic and routinely walk barefoot in pool or locker room areas; live or work in crowded conditions; share clothing, shoes, towels or grooming items; or have been exposed recently to someone with symptoms of ringworm.

If your symptoms involve the scalp or beard, you should be seen by a doctor before attempting any treatment.

Expected duration of ringworm

With proper treatment, both jock itch and ringworm of the body usually improve within one to two weeks. Ringworm of the scalp or beard may take a few weeks longer. However, athlete's foot can be a chronic (long-lasting) problem that comes and goes over many years. This can be caused in part by an active lifestyle that keeps the feet moist and sweaty.

Preventing ringworm

To help prevent tinea, try the following suggestions:

• Avoid sharing anyone else's clothing, shoes, towels, or personal-grooming items (hairbrushes, combs, makeup brushes).
• If your child goes to sleepover parties, provide a sleeping bag, pillow, and blanket from home.
• Bathe regularly and dry your skin thoroughly afterwards. Be especially careful to dry the area between your toes and under your breasts.
• Wear clean socks and underwear every day. When possible, choose absorbent cotton socks and underwear rather than synthetic fabrics. At the gym, keep an extra pair of socks in your locker to replace sweaty socks after a workout.
• Wear sandals, flip-flops, shower shoes, or other protective footwear when you walk through locker rooms or shower rooms or near pools.
• If you care for a pet or farm animal that develops areas of hair loss or scaly patches, take the animal to a veterinarian for a checkup.

Treating ringworm

If you have jock itch, athlete's foot, or ringworm of the body, you usually can be treated with a nonprescription antifungal cream, lotion, or powder. Your doctor can recommend the appropriate treatment for your condition. Some of the nonprescription topical medications available include terbinafine (Lamisil), tolnaftate (Tinactin), miconazole (Micatin and other brand names), clotrimazole (Lotrimin, Mycelex), and undecylenic acid (Desenex and other brand names). Be sure to follow the directions carefully when you apply the medication.

If your symptoms do not improve significantly after you have used a nonprescription medicine for about two weeks, call your doctor. Your doctor may suggest a prescription antifungal medication that will cure the problem. For extremely stubborn infections, the antifungal medication may be taken by mouth rather than being applied to the skin.

If you have a fungal infection of the scalp, beard, fingernails, or toenails, your doctor may treat you with an oral antifungal medication, such as oral terbinafine (Lamisil), itraconazole (Sporanox) or griseofulvin (Grisactin and other brand names). You also will have to apply antifungal creams or shampoos to your hair and scalp. Complete treatment can take two or three months.

When to call a professional

Make an appointment to see your doctor if you have symptoms of ringworm that involve the scalp or beard. Ringworm can sometimes be confused with other skin problems. If in doubt, see your doctor for a correct diagnosis.

If your immune system is weakened by illness or medication, contact your doctor promptly whenever you develop any unusual skin symptoms. In particular, people with diabetes should have skin symptoms, especially on the feet, checked as soon as possible.

Prognosis

Although treatment may take several weeks, antifungal medication almost always cures ringworm infections. Hair eventually regrows, and scarring is rare.

However, people do not develop immunity to tinea. Because it is possible to catch the fungus again, follow the suggestions outlined in the Prevention section above to avoid getting infected again.

Additional info

Centers for Disease Control and Prevention (CDC)
https://www.cdc.gov/

National Institute of Allergy and Infectious Diseases (NIAID)
https://www.niaid.nih.gov/

National Institute of Arthritis and Musculoskeletal and Skin Diseases
https://www.niams.nih.gov/

American Academy of Dermatology
https://www.aad.org/