Dermatophytosis is a type of dermatomycosis in which the superficial skin layers containing keratin are affected. The disease is caused by filamentous fungi of three types: Trichophyton, Microsporum, Epidermophyton. Pathology affects smooth skin, skin folds, scalp, nail plates. To accurately diagnose the infectious process, microscopy of scraping from the affected lesion, a culture method, and an examination using a Wood lamp are used. Treatment of cutaneous mycosis is usually carried out with local drugs, requires the selection of antifungal, anti-inflammatory, keratolytic and antiseptic agents.
ICD 10
B35 Dermatophytosis
General information
Dermatophytosis is one of the most common, difficult to treat skin diseases, accounting for more than 30% of all dermatological pathology. In addition, anthropophilic dermatophytes are currently found in 20% of the population, but they can act as a component of opportunistic flora, therefore they do not always have clinical symptoms. Treatment of the disease requires careful selection of medications and long-term medical supervision, so the disease is a serious problem for practicing dermatovenerologists.
Causes
In modern dermatology, 30 types of pathogens have been described that can cause superficial fungal diseases of the skin. There are fungi that parasitize exclusively in humans (anthropophilic), and others that affect humans and animals (zoophilic). Pathogens of the following genera are pathogens of diseases:
- Trichophyton. The genus Trichophyton unites filamentous (micellar) fungi capable of forming spores. The main causative agents of dermatophytia in humans: T. concentricum, T. rubrum, T. interdigitale.
- Microsporum. In morphology and pathogenicity factors, the genus Microsporum is similar to Trichophyton, and the main difference is the roughness of the macroconidium wall. Typical representatives of this group are M. audouinii, M. ferrugineum.
- Epidermophyton. This genus of fungi is characterized by multiple smooth club-like macroconidia. The most common type of pathogen in humans is Epidermophyton floccosum.
Pathogens of pathology are resistant in the environment, can survive outside the host body for 2 years. They are common on various surfaces: in the ground and sand, on wooden decking and seats. Various types of mushrooms are able to exist at high and certain temperatures, in a large pH range, they can withstand freezing, drying, boiling. This explains the high prevalence of superficial mycoses.
Risk factors
Predisposing factors of diseases in young people include chronic skin microtraumatization — domestic injuries, wearing tight uncomfortable clothes and shoes, unprofessionally performed manicure and pedicure procedures. In the older age group, vascular diseases occupy the first place among risk factors (21%), obesity is in second place (17%), various foot pathologies are in third place (15%). An increased risk of dermatophytosis is present in diabetes mellitus, hyperhidrosis, immunodeficiency states.
Pathogenesis
The main way of spreading fungi is contact and household. Infection with the disease is possible at the time of direct contact with a sick person or carrier, indirect infection is often observed — with the joint use of household items, in contact with surfaces contaminated with dermatophytes. Infection occurs more often in swimming pools, fitness centers, beauty salons, if sanitary standards are not observed in these institutions.
The probability of infection by contact with pathogenic fungi depends on several factors: the massiveness of the infecting dose, the presence of special receptors on the surface of microorganisms, the degree of pathogenicity of the pathogen. Of great importance in pathogenesis is the reduction of local protective factors, violation of the barrier functions of the epidermis, the activity of immunity.
A distinctive feature of all pathologies — mycoses affect the surface layers of the skin (often within the epidermis) and its appendages, which is due to the peculiarities of the pathogen’s vital activity. Pathogenic fungi that cause skin disease need ready-made organic molecules for growth and development. The protein keratin is an ideal nutrient. This protein is found in the stratum corneum of the epidermis, hair and nails.
Mushrooms have specific “aggression factors” that help them overcome the skin barrier. The main damaging agent is the proteolytic enzyme keratinidase, which breaks down keratin into amino acids and peptides. It performs two functions at once: it provides the cells of the fungus with nutrients, promotes the penetration of the pathogen between the layers of the epidermis, its deeper penetration into the skin.
Symptoms
Dermatophytosis of the scalp
Microsporia is the most common of this group of diseases in the practice of dermatologists. It is distinguished by one or more foci of 2-5 cm in size, which are clearly limited and do not tend to merge. The skin in such places is covered with multiple white scales, characterized by the formation of bubbles, erosions, crusts. The hair breaks off at a height of 4-6 mm, has a dull grayish tint. Hair loss along the periphery of the foci is typical.
Trichophytia is less common, which differs from microsporia by the smaller size of the foci (up to 2 cm in diameter), as well as by breaking off the hair directly near the root, which causes the second name of the disease “lichen of black dots”. Also, this group of dermatophytes includes favus, which is manifested by the formation of dirty gray crusts with an unpleasant odor. In severe cases, such crusts spread over the entire surface of the head.
Dermatophytosis of nails
Dermatophytes account for up to 70-90% of all cases of mycosis of the nail plates (onychomycosis). Taking into account the localization of the focus, pathology is divided into distal-lateral, proximal, and superficial forms. The distal variant of onychomycosis is more common, when the fungal lesion affects the free edge of the nail plate, gradually spreads to the germ zone.
When dermatophytosis occurs in the nail area, yellow spots appear on their surface, the nail plate becomes dull and brittle, foci of hyperkeratosis develop. Due to a violation of nutrition and blood supply, the destruction of the nail begins, and in difficult cases, onycholysis occurs (detachment of the horny plate from the nail bed). With the long-term existence of the disease, there is a risk of atrophy of the subcutaneous tissues.
Dermatophytosis of the hands and feet
The lesion of the lower extremities is much more common than dermatophytia of the hands. From this group of diseases, foot rubrophytia is often diagnosed, which occurs with a bilateral lesion, and with a prolonged course is supplemented by a fungal infection of the palm skin (usually the working brush). The disease is manifested by redness, peeling, thickening of the skin of the entire surface of the foot.
With epidermophytosis, the interdigital spaces of the 3rd and 4th toes are most often involved in the process. A crack appears in the crease between the fingers, which is surrounded by white stripes of the damaged epidermis along the edges and is located on a hyperemic base. Patients experience pain when touching, wearing tight shoes. Over time, an unpleasant odor occurs, the lesion spreads to neighboring areas.
Dermatophytosis of smooth skin
This type of disease is less common than others, mainly manifested by rubrophytia or microsporia. Mycoses caused by zoophilic dermatophytes are extremely rarely diagnosed. For this type of mycosis, annular foci are pathognomonic, which have uneven edges and gradually increase in size. The lesion area has a bright red color, is covered with peeling, subjectively itching is observed.
The same category includes dermatophytes of large folds, which mainly occur in the inguinal zone, in the armpits, on the inner side of the thigh. Clinically, they are manifested by redness and swelling of the skin, soreness and itching, which are intensified against the background of constant skin friction, aggravated by increased sweating in the hot season. It is possible to attach wetness, erosion.
Complications
If timely treatment is not carried out, then dermatophytosis of the hairy areas of the head and smooth skin turn into an infiltrative suppurative form. It is characterized by the formation of large foci — kerions, which are dense red or cyanotic skin covered with multiple pustules, nodules, purulent-hemorrhagic crusts. Often, without adequate treatment, the condition is accompanied by an increase in body temperature, headaches, intoxication syndrome.
All types of dermatophytosis can be complicated by the addition of a secondary bacterial infection requiring special treatment. Due to the damage to the outer keratin layer, pathogens penetrate much faster into the thickness of the epidermis and dermis, which is also facilitated by multiple erosions, combs, and other elements of the rash. At the same time, purulent inflammation is observed in the focus of infection, pustules appear, signs of intoxication increase.
Diagnostics
The basis of diagnosis is a thorough clinical examination of the patient by a dermatologist. At the initial reception, it is necessary to find out complaints, anamnesis of the disease, to detect the localization of the lesion and typical skin symptoms of a fungal infection. To choose an effective treatment for the disease, the doctor will need the results of laboratory and instrumental diagnostic methods:
- Inspection under Wood’s lamp. A quick test is performed at a specialist’s appointment: when the skin is illuminated with a fluorescent lamp, a greenish glow is detected, which is a pathognomonic sign of mycosis. Healthy skin turns light blue.
- Skin scraping. Microscopic examination of samples of the affected skin is the main method for detecting mycelium of fungi. If necessary, the hair from the lesion is examined. For 100% diagnostics, microscopy is supplemented by seeding the material on nutrient media to study the growth of fungal colonies.
- Additional analyses. With long-term, poorly treatable or recurrent processes, it is recommended to study the indicators of immunograms, biochemical blood tests. To assess the general state of health, clinical blood and urine tests are prescribed.
- Consultations of specialists. If a concomitant pathology is suspected, provoking or complicating the course of dermatophytia, the patient is sent for an extended examination to an allergist-immunologist, endocrinologist, cardiologist.
Treatment
The principles of therapy are based on the early removal of the causal factor — a pathogenic fungus, for which etiotropic drugs are used. Complex treatment requires the elimination of triggers that aggravate skin mycosis and prevent its healing. Proper skin care is also prescribed: according to the indications, patients switch to pharmacy products to restore the protective barrier, prevent the re-development of infection.
Often, treatment is carried out in two stages. At the first preparatory stage, it is necessary to remove acute manifestations of skin inflammation, eliminate wetness, foci of hyperhidrosis, and other lesions that may worsen the effects of the use of antimycotics. At the second stage, etiotropic therapy is recommended. The following groups of drugs are used for treatment:
- Antimycotics. Medications are selected according to the sensitivity of the isolated pathogen, and broad-spectrum medications are used until laboratory data are obtained. Preparations of the azole and allylamine groups are effective in dermatophytosis. The duration of therapy varies from 1-2 months to 1 year.
- Antibiotics. The addition of a microbial infection requires the appointment of etiotropic agents for the destruction of microbes. For quick and effective help, combined treatment with creams, which contain 3 components at once: antifungal, antibacterial, anti-inflammatory, is often effective.
- Corticosteroids. Topical and systemic drugs are required for treatment in the acute period, accompanied by a pronounced exudative component. Treatment is aimed at reducing swelling, redness, wetness, reducing the level of subjective unpleasant sensations.
- Keratolytics. In the hyperkeratotic form of the lesion (mainly on the feet), it is necessary to soften the horny layers with salicylic ointment, milk-salicylic talkers. This allows antimycotics to penetrate deeper into the affected skin and accelerates treatment.
To increase the effectiveness of treatment, drugs that improve microcirculation are used, which is especially important in patients with vascular diseases. To correct the immune status, treatment is supplemented with vitamin and mineral complexes, adaptogens, immunomodulators. For daily treatment of the affected areas, lotions with antiseptics, bandages with wound healing agents are used.
Physiotherapy techniques play an important role: amplipulse therapy, diathermy, UHF. They contribute to the destruction of fungal infection, disinfect the skin, accelerate the healing of affected areas. In case of nail pathology, it is recommended to conduct a hardware medical manicure / pedicure, which has a therapeutic and aesthetic function.
Prognosis and prevention
Since dermatophytosis is characterized by a superficial lesion of the skin, they are successfully amenable to therapy, rarely cause serious complications. Onychomycoses resistant to antifungal drugs are considered the most unfavorable and require prolonged treatment (for a year). The basis of disease prevention is the observance of personal hygiene measures, control over the sanitary condition of public places.
