RINGWORM

'Ringworm', also known as "Tinea", is a contagious fungal infection of the skin, and can exist anywhere on the body. Contrary to its name, ringworm is not caused by a worm, but generally is a reddish to brownish raised or bumpy patch of skin that may be lighter in the center, giving the appearance of a 'ring'.
Fungi are tiny organisms that survive by eating plant or animal material. The ringworm fungi feed on keratin, the material found in the outer layer of skin, hair, and nails. These fungi thrive best on skin that is moist, hot, and hidden from the light. When this infection is found on the feet, it is commonly called athlete's foot; when it is found in the groin it is commonly called jock itch; and when it is found on the body it is still called ringworm. Up to 20 percent of the population has one of these infections at any given moment.

Contents

Transmission

Types

Symptoms and diagnosis

Treatment

Prevention

See also

References

Transmission

Ringworm is very common, especially among children, and may be spread by skin-to-skin contact, as well as via contact with contaminated items such as hairbrushes. Ringworm spreads readily, as those infected are contagious even before they show symptoms of the disease. Participants in contact sports such as wrestling have a risk of contracting the fungal infection through skin-to-skin contact.
Ringworm is mildly contagious. Ringworm is also a common infection in domestic animals, especially cattle and cats. It can be caught from domestic animals (especially dogs and cats) as well as most farm animals. Humans can contract ringworm from animals; cats, cattle and dogs are common sources owing to close association with humans. Chickens may also be a source, due to the dirty conditions in which many poultry must live in which ringworm may thrive.
Ringworm can also be caught from other humans, both by direct contact and by prolonged contact with flakes of shed skin (from sharing clothes or from house dust, for instance).
To catch ringworm, you have to be exposed to it and you have to be susceptible. Some people are much more susceptible than others. Those with eczema or other skin problems get ringworm more easily because the protective barrier of the skin's outer layer is less intact. Children are more susceptible before puberty. Boys get it more easily than girls. Some people are genetically predisposed, and can get it easily throughout life.

Types

A number of different species of fungi cause ringworm. Dermatophytes of the genera ''Trichophyton'' and ''Microsporum'' are the most common causative agents. These fungi attack various parts of the body and lead to the following conditions:

★ Dermatophytosis

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★ ''Tinea pedis'' (athlete's foot) affects the feet

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★ ''Tinea unguinum'' affects the fingernails and toenails

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★ ''Tinea corporis'' affects the arms, legs, and trunk

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★ ''Tinea cruris'' (jock itch) affects the groin area

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★ ''Tinea manuum'' affects the hands and palm area

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★ ''Tinea capitis'' affects the scalp

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★ ''Tinea barbae'' affects facial hair

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★ ''Tinea faciei'' (face fungus) affects the face

★ Other superficial mycoses

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★ ''Tinea versicolor''

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★ ''Tinea nigra''

Symptoms and diagnosis

The best known sign of ringworm in people is the appearance of one or more red raised itchy patches with defined edges, not unlike the herald rash of Pityriasis rosea. These patches are often lighter in the center, taking on the appearance of a ring. If the infected area involves the scalp or beard area, then bald patches may become evident. The affected area may become itchy for periods of time. If the nails are affected, they may thicken, discolor, and finally crumble and fall off.
Doctors can diagnose ringworm on sight, or they may take a skin scraping, or in the case of animal ringworm or tinea capitis, examine plucked hairs for fungal elements. This is examined under a microscope, or put on an agar plate in a microbiology laboratory and allowed to grow. Some of the fungi fluoresce under a black light examination.
In domestic animals, ringworm can cause a variety of symptoms, but most cases show scaling and patches of hair loss. Some cats can be carriers, but show no symptoms.
Sometimes a ringworm infection may cause skin lesions in a part of the body that is remote from the actual infection. Such lesions are called "dermatophytids". The lesions themselves are fungus-free, and normally disappear upon treatment of the actual infection. The most common example is an eruption in the hands resulting from a fungus infection of the feet. Dermatophytids are essentially a generalized allergic reaction to the fungus.

Treatment

The treatment for ringworm is one of the many effective topical antifungal creams, such as miconazole (Tinactin) or clotrimazole (Lotrimin). Several of these antifungal creams are now available without a prescription. Treatment may require several weeks. Only by treating for at least one week after the resolution of symptoms can one guarantee eradication. (Pets can be treated with the same medicines, but this is difficult, since they often don't get a rash with their infections. Contact your pet's veterinarian to get up-to-date information on the best treatment for animals).
Topical antifungal drugs containing miconazole, clotrimazole, terbinafine, butenafine and tolnaftate, many available without a presciption, are used to clear up the infection. Brand names include Micatin, Tinactin, Monistat, Lotrimin, Bentax, Butop(India) and Lamisil. Generic equivalents may be available.
Treatment may be obstructed by itching, burning, cracking, and scaling that accompany this condition and prevent effective treatment. Ointments may be mixed with hydrocortisone creams such as Cortaid to reduce inflammation and speed recovery. Fungal infections may take a while to clear up, but most ringworm infections should see improvement in a week or two. Types affecting the nails or scalp are very difficult to treat due to fungal infection in follicle roots or under the nail itself.
Griseofulvin is a traditional drug used to treat ringworm in both animals and people. It can be very effective, but likely requires a prescription and may produce side effects. In cats and cattle, sulfurated lime rinses are often used to treat ringworm; and dilute povidone iodine may be used as a wash in cattle. Enilconazole, as a rinse, is an effective ringworm treatment available in many countries for treating animals.
Lufenuron, the active ingredient in Program oral flea treatment, is also commonly prescribed by vets to treat ringworm infections in cats and dogs.
Folk remedies for ringworm include a 1:1 solution of cider vinegar and water. Another alternative is 2 drops of tea tree oil mixed with an ounce of water. Undecylenic acid (Castor oil derivative) has also been effective for some.
If conditions do not improve after a couple weeks, consult your medical provider.

Prevention

Fungi thrive in warm, moist areas, such as locker rooms and swimming pools, and in skin folds. The fungi may be present without any symptoms. To prevent ringworm:

★ Do not share clothing, sports equipment, towels, or sheets. If you think you have been exposed to ringworm, wash your clothes in hot water with fungus-killing (fungicidal) soap.

★ Wear slippers or sandals in locker rooms, showers, and public bathing areas, especially during treatment.

★ Shower and shampoo thoroughly after any sport that requires skin-to-skin contact.

★ Wrestlers should regularly inspect the skin before practice, use protective bandages over infections while practicing or avoid competition until 1 week after symptoms resolve, and thoroughly disinfect gym pads and equipment.

★ Wear loose-fitting cotton clothing. Change your socks and underwear at least once a day.

★ Keep your skin clean and dry. Always dry yourself completely after showers or baths.

★ If you have athlete's foot, put your socks on before your underwear so that fungi do not spread from your feet to your groin.

★ Take your pet to the vet if it has patches of missing hair, which could be a sign of a fungal infection.

★ Continue topical remedies for 2 to 4 weeks after symptoms have resolved.

★ To prevent ringworm from returning after treatment, apply talcum or other drying powder to the affected area daily.

See also

★ Folliculitis

★ Pityriasis rosea

★ Antifungal drugs

References

The Merck Manual, Twelfth Edition, 1972, p. 1451