Favus(redirected from crusted ringworm)
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a skin disease that is caused by a fungus of the genus Achorion. Favus usually spreads through direct contact with sick persons or infected objects, more rarely through contact with such animals as cats, rats, or mice. Children are especially susceptible. In most cases the scalp is affected, although the smooth skin and nails are other possible sites of infection. Crusty, yellow, compact, saucer-shaped formations, which are called scutula and which have an unpleasant mousy odor, surround a central hair; they form within the horny layer of the epidermis and consist of pure cultures of the fungus. Hair easily falls out from the affected areas and is lackluster, ashy gray, and dry. The scutula leave atrophic scars over which hair cannot grow back. Scutula also can appear on smooth skin, but these do not develop into atrophic scars. Affected nails are usually thickened, nodular, yellow, and brittle. The treatment for favus is the same as for superficial trichophytosis.
(in animals), a fungal infection caused in birds by Trichophyton gallinae (Achorion gallinae) and in mammals by T. quinckeanum, which is also pathogenic for man. The fungus and its spores are transmitted by direct contact and by grooming implements. Mice and rats transmit favus to dogs, cats, and rabbits.
Among birds, the young of chickens and turkeys are most commonly affected. A dry, thick whitish gray layer consisting of the mycelium and spores of the fungus appears on the comb and wattles. In advanced stages of the disease, the feathers on the breast and head are affected and bald spots appear; the birds become emaciated and die. In cats, dogs, and rabbits, thick, dry whitish yellow crusts called scutula form on the head and occasionally on the body. The hair becomes dry and falls out. The fungus is sometimes localized in the claws.
Commercially valuable animals and birds are treated with phenol solution, Creolin, or a 2-percent solution of Formalin. Favus is prevented by isolating infected animals, exterminating rodents, killing acutely infected birds and animals, and disinfecting the animals’ and birds’ quarters.
REFERENCEKashkin, P. N. Dermatomikozy (cheloveka i zhivotnykh), 3rd ed. Leningrad, 1967.
V. P. KOROLEVA