Ringworm

Ringworm is a skin infection caused by a fungus that spreads out in an even circle, characterized by ring-like, scaly patches of red skin

Ringworm

Symptoms of Ringworm Infections

Ringworm can affect skin on almost any part of the body as well as fingernails and toenails. The symptoms of ringworm often depend on which part of the body is infected, but they generally include:

• Itchy skin
• Ring-shaped rash
• Red, scaly, cracked skin
• Hair loss

Symptoms typically appear between 4 and 14 days after the skin comes in contact with the fungi that cause ringworm.

Symptoms of ringworm by location on the body:

• Feet (tinea pedis or “athlete’s foot”): The symptoms of ringworm on the feet include red, swollen, peeling, itchy skin between the toes (especially between the pinky toe and the one next to it). The sole and heel of the foot may also be affected. In severe cases, the skin on the feet can blister.
• Scalp (tinea capitis): Ringworm on the scalp usually looks like a scaly, itchy, red, circular bald spot. The bald spot can grow in size and multiple spots might develop if the infection spreads. Ringworm on the scalp is more common in children than it is in adults.
• Groin (tinea cruris or “jock itch”): Ringworm on the groin looks like scaly, itchy, red spots, usually on the inner sides of the skin folds of the thigh.
• Beard (tinea barbae): Symptoms of ringworm on the beard include scaly, itchy, red spots on the cheeks, chin, and upper neck. The spots might become crusted over or filled with pus, and the affected hair might fall out.

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Ringworm on the arm

Diagnosis

Ringworm infection is diagnosed with a combination of physical examination findings, microscopy, wood's lamp and culture techniques.

Physical examination

A thorough history and physical examination is often sufficient to diagnose tinea. The classic lesion is an erythematous, raised, scaly ring with central clearing. Multiple lesions may be present. The severity of the infection can range from mild, scaly lesions, to erythematous, exudative lesions characteristic of superimposed bacterial infections.

Microscopy

Potassium hydroxide (KOH) stain a commonly-used method for diagnosing tinea because it is inexpensive, easy to perform, and has high sensitivity. Scrapings from the lesion(s) are placed in a drop of KOH and examined under a microscope for the presence of fungal hyphae.

Ultraviolet light (Wood’s lamp)

Normally, ultraviolet light is not useful in the diagnosis of tinea with the exception of two species – Microsporum canis and audouinii. Although both species fluoresce blue-green under a Wood’s lamp, both species are uncommon causes of tinea infections. A Wood’s lamp may be useful to differentiate between erythrasma caused by Corynebacterium minutissimum (which fluoresces coal-red) from tinea cruris, which is non-fluorescent.

Culture

Fungal culture can be performed as a confirmatory test if results from a KOH stain are inconclusive. Hair and/or scrapings extracted from affected areas are placed on Sabouraud’s medium. Fungal culture is more specific than KOH stain, but it can take up to three weeks to become positive.

Treatment

Tinea pedis: Athlete’s foot can usually be treated with over-the-counter topical antifungal products; terbinafine appears to be most effective, but other agents can also be used. Chronic or extensive tinea pedis may require treatment with oral antifungal agents such as terbinafine, itraconazole, or fluconazole. In addition, chronic tinea pedis may require adjunctive therapy such as foot powder or talcum powder to prevent skin maceration.

Tinea capitis: Treatment with systemic antifungal medication is required, as topical antifungal products are ineffective for treatment of tinea capitis. Many experts consider griseofulvin to be the drug of choice.6 Terbinafine is also FDA-approved for the treatment of tinea capitis in patients four years of age and older. Itraconazole and fluconazole have been shown to be safe and effective, but are not FDA-approved for this indication. Selenium sulfide shampoos can be used as adjunctive therapy.

Tinea corporis/cruris: Tinea corporis and tinea cruris can usually be treated with over-the-counter antifungal products. Patients who have tinea cruris should be advised to keep the groin area clean and dry and to wear cotton underwear. Persons who have extensive or recurrent infections may require systemic antifungal therapy.

Prevention

• Keep your skin clean and dry.
• Wear shoes that allow air to circulate freely around your feet.
• Don’t walk barefoot in areas like locker rooms or public showers.
• Clip your fingernails and toenails short and keep them clean.
• Change your socks and underwear at least once a day.
• Don’t share clothing, towels, sheets, or other personal items with someone who has ringworm.
• Wash your hands with soap and running water after playing with pets. If you suspect that your pet has ringworm, take it to see a veterinarian. If your pet has ringworm, follow the steps below to prevent spreading the infection.
• If you’re an athlete involved in close contact sports, shower immediately after your practice session or match, and keep all of your sports gear and uniform clean. Don’t share sports gear (helmet, etc.) with other players.

Preventing transmission via pets

Ringworm can easily transfer from animals to humans.You can take the following steps to protect yourself and your pet:

For people

Do

• Wash your hands with soap and running water after playing with or petting your pet.
• Wear gloves and long sleeves if you must handle animals with ringworm, and always wash your hands after handling the animal.
• Vacuum the areas of the home that the infected pet commonly visits. This will help to remove infected fur or flakes of skin.
• Disinfect areas the pet has spent time in, including surfaces and bedding.
  • The spores of this fungus can be killed with common disinfectants like diluted chlorine bleach (1/4 c per gallon water), benzalkonium chloride, or strong detergents.
  • Never mix cleaning products. This may cause harmful gases.

Do not handle animals with ringworm if your immune system is weak in any way (if you have HIV/AIDS, are undergoing cancer treatment, or are taking medications that suppress the immune system, for example).

For pets

Protect your pet’s health

• If you suspect that your pet has ringworm, make sure it is seen by a veterinarian so treatment can be started.
• If one of your pets has ringworm, make sure you have every pet in the household checked for ringworm infection.

Please click here for more information about pets and ringworm.

Please click here for information about how to stay healthy at petting zoos and other animal exhibits.

Preventing transmission at school

• Contact your local health department for more information.
• Tell your child not to share personal items, such as clothing, hairbrushes, and hats, with other people.
• Take your child to see a pediatrician if he or she develops ringworm symptoms.
• Check with your child’s school or daycare to see if he or she can still attend classes or participate in athletics.

Ringworm Resources
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