Ringworm has nothing to do with worms
The red, scaly ring on the skin looks as if something is burrowing underneath, hence the name ringworm. The real culprit is a fungus, one of about 40 species, and at any moment up to a fifth of the world's population may be carrying some form of the infection.
Doctors call it dermatophytosis or tinea, a fungal infection that can take hold in skin, hair and nails. The classic sign is an itchy, flaky, circular patch that is often redder at its outer edge, and hair may fall out where it strikes. Symptoms usually show up between four and fourteen days after exposure. Most cases are caused by fungi from three groups, Trichophyton, Microsporum and Epidermophyton, with the first two the commonest.
The same infection gets different names depending on where it lands. On the feet it is athlete's foot, or tinea pedis; in the groin it is jock itch; on the scalp, tinea capitis, which can leave bald patches. Nails, beards, hands and faces all have their own versions, and nail infection is also known as onychomycosis. The Latin labels describe the pattern of disease rather than naming the organism. Tinea versicolor, despite the name, is not true ringworm because it comes from a different fungus, Malassezia furfur.
These fungi love warmth and damp: locker rooms, swimming pools, tanning beds and skin folds. They pass between people via shared towels, shoes, hairbrushes or gym machines that nobody wiped down, and they also jump between people and pets such as cats and dogs, which makes ringworm a zoonosis. Wrestlers and other contact-sport athletes, people who sweat heavily, and those with obesity or weak immunity face higher risk.
Patterns differ by group: children are most prone to scalp infections, groin infections are most common in older people and more frequent in men, while body and scalp infections affect both sexes equally. Doctors can usually tell from appearance, confirming with a culture or by viewing a scraping treated with potassium hydroxide under a microscope. Topical antifungals such as clotrimazole are the usual treatment, with oral drugs when the scalp is involved. Accounts of the condition go back to ancient times.
Source: Dermatophytosis
