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Pathology => Human Diseases => Ringworm
Ringworm
Ringworm, infection of the skin, hair, or nails caused by various kinds of fungi that belong to the genera Trichophyton, Epidermophyton, and Microsporum. Ringworm tends to infect moist areas of the body, such as the groin, between the toes, and under the arms. The affected area usually becomes inflamed and itchy because of sensitivity to the fungus or a secondary infection by bacteria. In the most serious cases, ringworm results in an acute infection that produces running sores on the scalp or painful blisters on the feet.
Petting infected dogs and cats often spreads ringworm to human beings, but it is usually passed through human-to-human contact. Even sharing clothes, combs, or towels may result in the spread of the infection.
Ringworm of the scalp, which occurs primarily in children, is the most contagious form of the disorder. It causes itching, and the hair may break off or fall out, giving the scalp a patchy appearance. Treatment requires that the hair be shaved off. An oral antifungal medication may be prescribed. Scalp sores must be kept clean and dry, and often the child is isolated to prevent the infection from spreading to other children.
Ringworm on the limbs, trunk, and face causes raised circular patches, which heal in the centers out as the patches widen. The condition derives its name from this circular pattern, though in the groin or armpit the patches may suggest butterfly wings, and at times the pattern is completely irregular. Ringworm of the beard usually occurs on only one side of the face and is often irritated by shaving. Ringworm may also affect the fingernails and toenails, causing thickening and deformation. When found on the feet, ringworm is called athlete's foot.
To diagnose ringworm, a physician scrapes off portions of the affected areas and examines them under a microscope. If a fungus is present, a characteristic type of growth will be evident. Some forms of ringworm of the scalp may be diagnosed by means of an ultraviolet light, which causes certain types of fungi to glow with a bright yellowish-green color.
Ringworm infections are often difficult to treat. Keeping the infected area clean and dry helps prevent growth and spread of fungus. Scraping of overgrown skin or nail tissue may be helpful, and various antifungal medications may be applied.
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