Dermatophytosis

Introduction to dermatophytosis Dermatophytosis is a shallow infection of hair, skin and nails caused by dermatophytes, but there are also reports of deep infections. Clinically common are head lice, body lice, and stocks., hand rubs, athlete's foot and plague. Occasionally, it can involve deep tissues and cause deep infections. Dermatophytes and their metabolites can cause allergic reactions to the skin outside the lesion through blood circulation, called dermatophytids. Dermatophytosis is a group of common and frequently-occurring diseases. In dermatology cases, it is inferior to dermatitis and eczema, and it ranks first in infectious skin diseases. In China, the number of patients is at least 100 million, so it is of great clinical significance and society to actively prevent dermatophytosis. significance. basic knowledge The proportion of illness: 0.003%-0.004% Susceptible people: no special people Mode of infection: contact infection Complications: cellulitis, folliculitis, foot swelling

Causes of dermatophytosis

(1) Causes of the disease

The dermatophytes have the characteristics of skin keratin. Currently, there are about 45 species, most of which are pathogenic to humans. According to the characteristics of colonies and large conidia, dermatophytes can be divided into trichophytons, microspores. Genusporum and epidermophyton, the fungal classification belongs to the genus Ascomycetes - the genus of the genus Aspergillus, some of which have been found to have sexual stages, and the proper environment of the host skin for the development of dermatophytosis It is very important that in addition to the injury, the increased moisture of the impregnated skin is also suitable for the growth of dermatophytes.

(two) pathogenesis

The proper environment of the host skin is very important for the development of dermatophytosis. Except for the injury, the increased moisture of the impregnated skin is also suitable for the growth of dermatophytes. The airtight clothing can increase the temperature and humidity of the skin and interfere with the stratum corneum. The barrier function, after the skin sputum invades the skin, has to go through several stages of development, including the incubation period, during the anti-infection process, the growth and degeneration period, the incubation period of dermatophytes in the stratum corneum, the clinical manifestations are slight, once the infection is established The growth rate of dermatophytes and the rate of epidermal renewal are two key factors for the development of damage. The former must be equal or the former is greater than the latter, otherwise the number of dermatophytes will decrease, and keratinase and other proteins produced by dermatophytes will be produced. Decomposing enzymes, not only related to their colonization and invasion in the skin, but also related to their virulence, direct damage to the keratinized tissue of the fungus (mainly hair and nail) and the result of the host inflammatory reaction, the latter varies, and the dermatophytes invade the hair to cause the head, occasionally a large bulge of purulent damage called purulent sputum, hair after infection, yellow or broken, skin Variety of clinical manifestations of bacterial fungal disease of keratinized tissue damage directly (primarily hair and A) and of the host inflammatory response, which is diverse, dermatophytes tinea corporis due to violation of the stratum corneum and tinea.

Dermatophytosis prevention

Improve the prevention and treatment organizations at all levels, carry out mass publicity and education, widely publicize the infection routes and methods of infection of dermatophytosis, preventive measures and the need for timely and thorough treatment, educate the masses to develop good hygiene habits, and abide by health Health care system, etc.

Carry out the principle of prevention and prevention, and implement a series of physical examination, isolation, management and treatment systems, and strive for early detection, early diagnosis and early treatment.

Complications of dermatophytosis Complications, cellulitis, folliculitis, foot swelling

Dermatophytes can cause deep tissue infections in rare cases, including cellulitis, folliculitis, purulent sputum, subcutaneous tissue abscess, lymph node abscess, Majocchii granuloma, foot edema, and verrucous hyperplasia.

Symptoms of dermatophytosis common symptoms pruritus, pustule abscess, crusting, skin granuloma, hair loss, nodular scales

Dermatophytes have traditionally been named according to anatomical parts, such as the body sputum, hand and foot sputum, etc. This classification method is beneficial to use different drugs according to the skin characteristics of different anatomical parts. Some dermatophytosis is also named according to pathogens, such as Astragalus, scorpion scorpion, red rickets and so on.

Skin sputum invades the hair and causes head lice, which is characterized by ring-shaped hair loss spots, scaly, blisters or pustules. Sometimes scattered hair loss spots may be the only symptoms. Occasionally, the suppurative lesions of large ridges are called purulent sputum, hair infection. After the yellow or broken, depending on the location of the hair infection, it can be divided into an internal infection and an external infection. The internal infection forms spores in the hair and can be filled in the hair or in a chain, also known as black sputum. For jaundice, hyphae are formed in the hair, and microspores such as dermatophytes form a large number of spores in the form of mosaics, which are mosaic or chain-like, and are called epidermal infections, also known as white sputum. Infections can sometimes find hyphae in the hair, especially at the roots.

The dermatophytes invade the stratum corneum and cause the femoral hernia and the hand and foot spasm. In the dander, the hyphae separated by branches can be broken into chain spores. The lesions are generally round or multi-ring, and are scattered or fused together. Tissue reactions can range from erythema, scaly to crusting, suppuration and even granuloma, subjectively without sensation or varying degrees of itching.

The fungus Scytalidium dimidiatum and its variant S. hylinum can cause human palmar and deck infections. The clinical manifestations and direct microscopic examination are not distinguishable from the hand, foot and ankle, so specimens are cultured. At the time, one of the tubes should not be added with cycloheximide to prevent the growth of Acremonium. The dermatophytes affect the deck, which is usually characterized by thickening, discoloration and damage of the deck. There is no inflammation or pain in the nail tissue. .

Dermatophytes can cause deep tissue infections in rare cases, manifested as cellulitis, folliculitis, purulent sputum, subcutaneous tissue abscess, lymph node abscess, Majocchii granuloma, foot edema, verrucous hyperplasia, etc. Yang Guoliang Two cases of deep infection caused by rust-colored microspores were reported. The patient's hair was sparse. The whole body saw large scaly lesions and skin granulomatous lesions. The latter was mainly nodules, widely distributed, and some perforated suppuration.

Examination of dermatophytosis

Fungal examinations help to identify dermatophytes, colony morphology, microscopic features, especially the size, shape, separation, cell wall characteristics and birth patterns of large conidia, is a must-check for this disease.

Histopathological examination: The multiple clinical manifestations of dermatophytosis are the result of direct damage to the keratinized tissue of the fungus (mainly hair and nail) and host inflammation, which varies widely and is visible in dry infections of Trichophyton rubrum. Simple hyperkeratosis, but the pus sputum caused by pro-animal dermatophytes is characterized by pustules. For example, T. rubrum can cause epidermal changes including chronic dermatitis with hyperkeratosis, keratinization. Incomplete, increased or decreased particle formation, edema of the spinous cell layer, mononuclear cell invasion and moderate, severe acanthosis, other changes including epithelial blisters in polycyclic erythematous lesions, vascular changes caused by allergic vasculitis, accompanied by lymph Cells, tissue cells, neutrophils and eosinophils can further develop granulomatous reactions, the epidermis and dermis are basically normal, while the middle layer of fungi can be seen near the dilated blood vessels, neutrophils, eosinophils, lymph Cells, tissue cells and plasma cells.

Pustules can occur under the horns and hair follicles. Folliculitis and periorbital inflammation are generally associated with the presence of fungal components in the hair follicle. Inflammatory changes range from the edema of the outer layer of the root sheath to the granulomatous granulomatous reaction with necrosis and foreign body Giant cells, possibly induced by hair ruptured by broken hair follicles, are characterized by subacute dermatitis and obvious folliculitis for the purulent sputum, diffuse granulomatous inflammatory response with foreign body giant cells, vascular changes and fibrosis, typically The ringworm has significant inflammatory changes at the edge of the lesion, including perivascular lymphocytic infiltration.

Diagnosis and diagnosis of dermatophytosis

According to clinical manifestations, histopathological features can be correctly diagnosed. The identification of dermatophytes is based on colony morphology, microscopic features, especially the size, shape, separation, cell wall characteristics and birth patterns of large conidia, sometimes combined with other Some tests such as nutrition tests, hair perforation tests, Wu's lamp tests and mating tests, etc., histopathological examination can help to confirm the diagnosis.

Identification of dermatophytes according to colony morphology, microscopic features, especially the size, shape, separation, cell wall characteristics and growth patterns of large conidia, sometimes combined with other tests such as nutrition test, hair perforation test, Wu's lamp Test and mating test, etc.

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