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Favus: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Favus is a rare chronic fungal disease affecting the scalp, long and fuzzy hair, smooth skin, nails and internal organs.
Causes and pathogenesis of favus. The causative agent of the disease is Trichophyton schonleinii. The source of infection is a person and his clothing. Contagiosity is low, however, long-standing family-household foci can arise. More often the infection is transmitted through the female line.
Symptoms of favus. On the scalp, there is a scutum, squamous (pitiodic) and impetiginous forms of the facial phavus of the scalp. The first form is typical for favus, the second form is atypical.
The scutulary form is ocher-yellow in color (scutula) with a saucer-shaped depression in the center. At the removal of the crust, atrophy or scars are found. In most patients, the scutes are permeated with dry, shiny and elastic hair that resembles a pakly. On the edge of the scalp (if the entire head is affected) there is a lack of lesion. Characteristic is the specific "mouse", "granary" smell from the patient's head.
With squamous (pitryroid) form, diffuse lamellar peeling is observed, resembling pronounced seborrhea. Under the scales are visible atrophic changes in the skin of the scalp.
Impetiginous form is characterized by the prevalence of crusts of yellow-brown color and is very similar to vulgar impetigo or eczematous process complicated by secondary infection.
After the removal of the crusts, atrophic changes in the skin of the scalp are also visible. Change of hair is the same as with other forms of favus.
The defeat of the skin is manifested by the formation, in addition to scutulum, hyperemic and flaky foci, which resembles a trichophytosis of smooth skin.
The most characteristic for the favus is the slow involvement of the nail plate in the process. Only the fingernails of the brushes are affected. In the center of the nail plate appears a brown or dirty-gray spot, which exists for a long time and, gradually expanding, captures the entire nail plate - subungual hyperkeratosis develops. Over time, the nails begin to crumble, but less than with other onychomycosis.
Secondary rashes may be superficial (lichenoid, erythematous, erythematous-squamous) and deeper (nodular, subcutaneous). They rarely find the fungus.
Lesions of the internal organs (lungs, gastrointestinal tract, chorionic lymphadenitis, and spinal meningoencephalitis) are observed in weakened, malnourished patients, as well as those suffering from tuberculosis infection. The search for a pathogen in these cases is carried out in sputum, feces, cerebrospinal fluid and the point of attic lymph nodes.
The diagnosis is based on the detection of scutum, cicatricial atrophy with alopecia and the presence of healthy hair on the periphery.
Differential diagnosis. Differentiate the disease from trichophytosis, microsporia, Brock's pseudo-pelvis, streptoderma, psoriasis, eczema, etc.
Treatment of favus. Conduct the same treatment measures as with trochophyte.
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