Trichophytosis

Trichophytosis is a fungal skin disease caused by fungi of the genus Trichophyton. According to the ecological characteristics of the pathogens, anthropophilic (affects only humans), zooanthroponotic (affects humans, farm animals and wild animals) and geophilic (affects humans and animals sporadically) trichophytosis are distinguished.

Anthropophilic (superficial) trichophytosis

The causative agents of this form of trichophytosis are Trichophyton tonsurans, s. crateriforme, T violaceum. The source of infection is a patient with trichophytosis. Infection occurs through direct contact with the patient or through his things (headwear, nail and bed linen, combs) that the patient used. The patient can become infected in hairdressers, kindergartens, schools and other children's institutions. A decrease in the immune system, endocrinopathies create favorable conditions for the development of the disease. In terms of frequency, this mycosis ranks second after microsporia. The causative agents of trichophytosis are divided into groups depending on the type of hair damage. There are two such main groups: endothrix (endothrix) - fungi that affect the inner part of the hair, and estothrix (ectothrix) - vegetating mainly in the outer layers of the hair. All endothrix trichophytons are anthropophiles, transmitted only from person to person. They cause superficial lesions of the skin, scalp, and nails. Ectotrix are zoophiles that parasitize primarily on animals, but can also infect humans. Compared to the endothrix group of fungi, they cause a more pronounced inflammatory reaction of the skin in humans.

Symptoms

The following forms of anthropophilic trichophytosis are distinguished: superficial trichophytosis of smooth skin, superficial trichophytosis of the scalp, chronic trichophytosis and trichophytosis of the nails.

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Superficial trichophytosis of smooth skin

Superficial trichophytosis of smooth skin manifests itself on any areas of the skin, but most often on open areas - the face, neck, forearms. Clearly defined lesions with peeling in the center have a round or oval shape, pale pink color. The peripheral zone of the lesions is surrounded by a more or less pronounced border of a spotty or nodular nature, which often has small bubbles and crusts. The lesions can merge, forming bizarre patterns. Itching in the area of the lesions is usually slight. The disease is acute, with rational treatment, clinical recovery occurs in 2 weeks.

In superficial trichophytosis of the scalp, foci of various sizes, round or irregular in shape, with fuzzy, blurred boundaries appear. Sometimes mild inflammation is observed. Hair in the lesions partially breaks off at a height of 1-2 mm or at the skin level. In the lesions, there is not a continuous lesion of hair, but rather a rarefaction (thinning). The extracted hair fragments look like commas, hooks, question marks. Short broken hair is often called "stumps". The bending of the hair affected by trichophyton, extracted with tweezers, is explained by its softness, as a result of which it cannot break through the scales. Sometimes the hair breaks off at the level of smooth skin ("black dots"). For examination under a microscope, it is recommended to take these "stumps" or "black dots". The surface of the lesions is covered with whitish scales. There are small- and large-focal variants of the course of this form of trichophytosis.

Chronic trichophytosis

Chronic trichophytosis is considered a variant of superficial trichophytosis and is also caused by the above-mentioned anthropophilic fungi T. violaceum and T. crateriforme. Women are predominantly affected. The disease begins in childhood with superficial trichophytosis of the scalp or superficial trichophytosis of the smooth skin. If left untreated during puberty, the disease spontaneously heals (often in men) or transforms into chronic trichophytosis, in the development of which an important role is played by endocrine disorders (dysfunction of the sex glands), hypovitaminosis, in particular vitamin A deficiency, etc. Skin, hair and nail lesions are noted. The lesions are mainly located in the occipital and temporal regions and are manifested only by minor bran-like whitish peeling. A pathognomonic sign is that the affected hair breaks off at the same level as the skin and resembles comedones. These broken hairs, which appear as “black dots”, are sometimes the only symptom of the disease.

Skin lesions in anthropophilic trichophytosis are characterized by the formation of pink spotted scaly rashes with a bluish tint on the body and face. Mild inflammation with lamellar peeling may be observed on the skin of the palms and soles. Some patients with severe concomitant diseases develop deep forms of trichophytosis ("trichophytosis gummas", tuberculous trichophytosis, furuncle-like, etc.). Nail plates are often involved in the pathological process.

Without treatment, trichophytosis can last for years in some children. The disease usually spontaneously heals only at the onset of puberty. In some patients, mainly women, untreated trichophytosis manifests itself differently, turning into chronic trichophytosis. In its pathogenesis, disorders of the autonomic nervous system, endocrinopathies (hypogenitalism, hypercorticism, diabetes, hypovitaminosis A, etc.) play a significant role. It should be borne in mind that chronic trichophytosis can also be observed in children. When examining patients with chronic trichophytosis, attention is paid to the condition of the scalp, smooth skin and nails. The most common manifestations of chronic trichophytosis on the scalp are: isolated hairs broken off at the mouths of hair follicles at the very surface of the skin in the form of black dots - "black-spot" trichophytosis), more often in the occipital and temporal regions, small round atrophic scars (1-2 mm in diameter) and minor fine-plate peeling.

On smooth skin, lesions are usually located in areas subject to friction (on the extensor surfaces of the elbow and knee joints, on the buttocks, shins, and less often on the torso), where large, poorly defined erythematous-squamous elements with mild erythema and fine-lamellar peeling of the surface are determined.

At the same time, a third characteristic sign of chronic trichophytosis can be detected - damage to the nail plates of the hands and feet, similar to onychomycosis.

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Trichophytosis of nails

Trichophytosis of the nails is mainly found in chronic trichophytosis in adults and begins with the free edge of the nail plate, which loses its normal shine.

Almost all nail plates are involved in the pathological process. A grayish-dirty spot is formed in the thickness of the nail. Over time, the affected nail plates become bumpy, crumble easily, the free edge of the nail plate is raised due to its splitting into several layers. Then the nail plate becomes black.

Zoonotic (infiltrative-suppurative) trichophytosis

The disease is caused by Trichophyton gypscum and Trichophyton verrucosum, which are zoophilic fungi. The incubation period for trichophytosis caused by Trichophyton verrucosum is 1-2 months, and for Trichophyton gypseum - 1-2 weeks. The above-mentioned pathogens parasitize rodents (mice, including laboratory mice, rats, etc.), cows, calves, less often - horses, sheep and other animals. The source of infection is sick animals, less often - a sick person.

Symptoms

Clinically, there are 3 forms of zoonotic trichophytosis: superficial, infiltrative and suppurative.

In the superficial form, large lesions with scalloped outlines appear on the affected skin due to their fusion with each other. The lesions are round, pink, their surface is covered with scales, and along the periphery there is a continuous ridge consisting of bubbles and crusts. The infiltrative form is characterized by the development of infiltration in the lesion and painful regional lymphadenitis.

Later, the inflammatory phenomena increase, and against the background of infiltration on the surface and in the foci, numerous folliculitis and yellow-brown crusts appear. After removing the crusts, it can be found that pus is released from each follicle separately, although the first impression is that the patient has one large and deep abscess. These foci are very reminiscent of honey released from a honeycomb (kerion Celsius - Celsius's honeycomb). Infiltrative and suppurative forms of trichophytosis when localized on smooth skin are less acute - foci of the kerion Celsius type almost never form on it. When the foci are located on the upper lip, cheeks and chin, the clinical picture resembles sycosis ("parasitic sycosis"). The pus present in the lesion is able to lyse (dissolve) the fungi, in connection with which cases of self-healing are noted. After the process is resolved, scars remain.

In infiltrative-suppurative trichophytosis, one or two sharply defined inflammatory nodes appear on the scalp, and in men also in the area of beard and moustache growth, protruding above the skin surface and painful to palpation. At first they have a dense consistency, and then soften. Their surface is covered with thick purulent-bloody crusts. The hair penetrating the crusts seems unchanged, but is easily removed when pulled. In places, more along the periphery of the lesions, follicularly located pustules are visible. After removing the crusts together with the hair, a hemispherical inflamed surface is exposed with many widened mouths of hair follicles, from which pus is released in drops when the lesion is squeezed. This form, known since ancient times by the name of the Roman physician Celsus who described it, is called kerion Celsi (Greek kerion - honeycomb).

At the height of development, mycosis is accompanied by an increase in regional subcutaneous lymph nodes and a violation of the general condition - malaise, increased body temperature. Often there are mycosis - secondary allergic nodular and spotty rashes on the trunk and limbs. After 2-3 months without treatment, the mycotic process subsides, the filtrate is absorbed, cicatricial alopecia remains and specific immunity is formed. Similar changes develop when the beard and moustache area is affected. This disease is called parasitic sycosis.

Zoonotic trichophytosis of the pubic area

Zoonotic trichophytosis of the pubic area was first described in scientific literature by S. S. Arifov, Z. M. Abidova and A. S. Lukyanova (2003). The authors examined 356 patients with zoonotic trichophytosis (237 men, 119 women). Of these, 141 were children under 14. In 215 of the 356 patients, the pathological process was located in the pubic area. 148 (68.8%) of the 215 patients associated their disease with sexual contact. Of these, 149 (69.7%) patients were found to have various STIs: ureaplasma - in 38.2%, gardnerella - in 21.2%; candida albicans - in 14.8%; chlamydia - 12.7%. syphilitic infection - in 4.2%; gonococci - 2.1%; trichomonas - in 2.1% and in 4.2% of patients the ELISA was positive for HIV infection.

From an epidemiological and preventive point of view, the authors propose to include pubic trichophytosis in the group of STIs.

Differential diagnosis

The disease should be distinguished from pyoderma, microsporia, psoriasis, etc.

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Treatment of trichophytosis

In case of superficial trichophytosis with damage to the skin only, the presence of single foci (without hair involvement), it is sufficient to use external agents. In local treatment, it is necessary to take into account the stage of inflammation (weeping, swelling, etc.), using lotions, pastes. After the acute inflammatory phenomena have been removed, 3-5% iodine solution, Castellani paint, travogen, lamisil, clotrimazole, mycospor, mycoseptin, etc. are prescribed as antifungal agents. The most effective in external therapy is lamisil in the form of a cream or gel. Experience in using this drug has shown that lamisil, as a fungicidal drug, allows for a high percentage of clinical and mycological recovery in a short time compared to other antimycotics. It is used once a day for a week. In case of damage to the scalp, multiple lesions of smooth skin with the involvement of vellus hair, systemic antimycotics are used. Griseofulvin is prescribed orally (at a daily dose of 18 mg/kg for children or 12.5 mg/kg for adults) or Lamisil (up to 20 kg - 62.5 mg, from 20 to 40 kg - 125 mg and over 40 kg and adults - 250 mg) once a day for 28 days.

In case of scalp lesions, a 2-5% iodine solution and antifungal ointments (Lamisil, Travogen, etc.) are applied externally. In the treatment of patients with chronic trichophytosis, it is advisable to use pathogenetic therapy and immunomodulators.

Prevention is carried out jointly with the veterinary service to identify sick animals and deratize them. It is necessary to examine the family members of the sick person and children's groups.