A fungal infection that produces itchy, red, circular patches on the scalp, groin, or elsewhere on the skin
- Age, gender, and lifestyle as risk factors depend on the type
- Genetics is not a significant factor
Despite the name, ringworm is caused not by worms but by fungi that infect the skin and cause itchy, red, ring-shaped patches. There are a number of common forms of the disorder, including scalp ringworm (tinea capitis), body ringworm (tinea corporis), and ringworm of the groin (tinea cruris).
Scalp ringworm, which is more common in children, can spread from one person to another or be acquired from cats and dogs. Ringworm of the groin mainly affects men, particularly those who have other fungal infections, such as athlete’s foot. All forms of ringworm are especially common in people with reduced immunity to infection due to disorders such as diabetes mellitus or AIDS (see HIV infection and AIDS).
What are the symptoms?
In all forms of ringworm, the following symptoms develop gradually over days or sometimes weeks:
Initially, a small, round, scaly, itchy, red patch appears.
After 1–2 weeks, more patches appear.
Each patch grows larger and forms a scaly, red ring around a central area of normal skin.
In scalp ringworm, hairs may break off just above the surface of the skin, leading to irregular patches of stubble (see Alopecia). In ringworm of the groin, the rash occasionally spreads further to affect the skin on the inside of the thighs and the buttocks.
What might be done?
Your doctor will probably recognize ringworm from its appearance and may confirm the diagnosis by taking a skin scraping. The removed skin is examined under a microscope to confirm the presence of fungal infection.
Topical antifungal drugs may be obtained by prescription from your doctor or over the counter (see Preparations for skin infections and infestations). If the ringworm affects your scalp or is widespread, you may be prescribed oral antifungal drugs, which you will need to take for several weeks to clear up the infection completely. If you have ringworm of the groin, you can help to prevent a recurrence by keeping the area clean and dry.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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