Ringworm is not a worm infestation, but an infection caused by a fungus. Doctors call the infection tinea or dermatophytosis. (See Health Profile for DERMATOPHYTOSIS.)
Fungal infections of the skin are surprisingly common. Unfortunately, when they have a name like ringworm, they cause panic and misunderstanding. Parents become emotional about this issue, feeling that they have been negligent in their child’s hygiene. School nurses may fear epidemics and demand that the child be removed from the school, returning only with a doctor’s note.
On the scalp, the fungi can cause round, bald, scaly patches (tinea capitis). The skin flakes and itches. A disease that mainly afflicts children, ringworm of the scalp can be contagious within a school or community, but can be generally treated effectively.
Body ringworm (tinea corporis) appears as a round or oval sore that is red, scaly, and itchy. The patch gradually grows bigger until it is about 1 inch across. The central area heals, leaving a red ring on the skin.
Athlete’s foot is called tinea pedis. Approximately 80 to 90 percent of all men and a smaller, but growing, percentage of women are afflicted with athlete’s foot.
The condition is caused by certain types of ringworm fungi called dermatophytes (See Health Profile for DERMATOPHYTOSIS) The fungi feed on keratin, a protein contained in dead skin cells. They need warmth and humidity to proliferate. Individual susceptibility to the fungi varies depending on immunological status.
The infection assumes one of three forms: localized between the toes; chronic infestation of the soles and sides of the feet; or itchy, fluid-filled blisters on the in-step, heel and ball of the foot.
The first form can usually be controlled with over-the-counter medications unless there is secondary bacterial infection requiring a physician’s help. The second form is usually treated by a physician, often with oral antifungal agents. The third type also requires oral medication.
Those afflicted should try to keep the feet cool and dry by wearing cotton or wool socks and vented or open shoes. Dry the feet thoroughly after bathing or swimming. Apply antifungal medication once or twice a day.
Tinea infections result from several different fungi. Transmission can occur directly through contact with infected lesions or indirectly through contact with contaminated articles, such as shoes, towels or shower stalls.
Most pediatricians do not recommend isolation of afflicted children. Covering the rash with a bandage and a layer of clothing is usually enough to prevent its spread.
Another predisposing factor is warm weather and tight clothing which encourages fungus growth.
Some of these fungi involved in these conditions primarily infect animals, but they may be transmitted from animals to humans. Cats may have an infection but may not be suspected until lesions appear on their owners.
Diagnosis must rule out other possible causes of the signs and symptoms, which may include eczema, psoriasis and contact dermatitis.
A microscopic examination of some lesion scrapings usually will confirm tinea infection. This is called a KOH (potassium hydroxide) preparation. Culture of the affected area, which may take weeks, may help identify the infecting organism.
For most types of tinea, treatment is with antifungal drugs in the form of skin creams, lotions or ointments. However, for widespread infections or those affecting the hair or nails, an antifungal drug in tablet form (usually griseofulvin) may be taken.
Treatment of small, uncomplicated lesions located in areas other than the scalp is by topical antifungal preparations such as ketoconazole (Spectazole), clotrizamole (Lotrimin, Mycelex), econazole (Spectazole) and miconazole nitrate (Monistat-Derm).
Lesions of the scalp, regardless of severity, should be treated with oral antifungal medication.
Griseofulvin (Fulvicin, Grisactin) may be required at high doses due to poor absorption. Itraconazole is another antifungal agent that can be taken orally. Oral antifungals and corticosteroids are indicated for treatment of widespread, severely inflammatory infections and potentially scarring lesions.
Do any tests need to be done to diagnose the condition?
What treatment will you be recommending?
What over-the-counter medication is most effective?
Will you be prescribing any medications? What are the side effects?
How long does it take to resolve fungal infections?
The skin should be kept dry, since moist skin favors the growth of fungi. Dry the skin carefully after bathing and let it it dry before dressing. Loose-fitting underwear is recommended. Socks should be changed daily. Sandals or open-toed shoes may be beneficial. Talc or other drying powders may also be helpful.