Ringworm

Ringworm - Most of these infections are caused by a group of keratinophilic
moulds known collectively asdermatophytes. They cause a complex of diseases, collectively
known as ringworm (clinical name Tinea), which affects the keratin in hair, nails
and stratumcorneum (top layer) of theskin. About 20 species of dermatophyte fungi
from the genera Trichophyton, Microsporumand Epidermo-phytonare responsible. Most
infections are caused by asingle species, Trichophytonrubrum.
Ringworms also occur in animals and these may spread to humans; transfer is
commonest with Microsporum canis, the cause of ringworm in cats and dogs. Ringworm
lesions vary considerably in appearance, according to the site of the infection
and the species of fungus involved. Sometimes there is only dry scaling orhyperkeratosis,
but more commonly there is irritation, inflammation, swelling and vesicles. More
inflammatory lesions with weeping vesicles, pustules and ulceration areusually
caused by animal ringworm.
The spreading, ring-like lesions with a raised, inflammatory border from which
the disease name derives are seen on the body, face and scalp. In infections of
the scalp there is scaling and hair loss and sometimes a severe inflammatory response
resulting in a raised boggy lesion called a kerion this needs to be diagnosed
and treated promptly otherwise there may be permanent hair loss. In nail infection,
the nail becomes discoloured, thickened, raised and crumbly. Ringworm is the only
truly contagious fungal infection and spreads through direct or indirect contact
with an infected individual or animal.
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