Squamous epidermophyton is one of the forms of fungal lesions of the palms or feet caused by the fungus Trichophyton mentagrophytes and characterized by moderate inflammation with signs of hyperkeratosis. Symptoms of this disease are the formation of plaques 1-4 centimeters in size on the skin of the feet or palms, hyperkeratosis and moderate itching. In some cases, plaques may be absent, the only manifestations of pathology are itching and peeling. Diagnosis of squamous epidermophytosis is based on the results of dermatological examination and microscopic examination of scrapings from lesions. The treatment of the disease is carried out similarly to the therapy of other mycoses of the feet or palms, but has a pronounced phasing.
Squamous epidermophyton (squamous-hyperkeratotic epidermophyton) is a type of palm–foot dermatomycosis, in which there is a violation of the processes of keratinization of the skin in the form of peeling and hyperkeratosis. By itself, infection with Trichophyton mentagrophytes of the skin of the feet and (to a lesser extent) of the palms is a very common condition observed in a huge number of people all over the planet. At the same time, the proportion of squamous epidermophyton in the overall structure of this disease is not exactly known, the clarification is complicated by the fact that various forms of pathology (including squamous hyperkeratotic) can pass into each other. This type of foot mycosis is considered the most contagious in dermatology, since the pathogen can persist for a long time on the abundantly released skin scales, which increases the likelihood of infection of other persons. The contagiousness of squamous epidermophyton increases significantly with erased forms of the disease, when there are no pronounced clinical symptoms, and the patient can, without knowing it, infect a huge number of people.
As already mentioned above, the cause of squamous epidermophytosis is infection of the skin with microscopic saprophytic fungus Trichophyton mentagrophytes, which is introduced through micro-tissue damage. Infection usually occurs when wearing the patient’s shoes, in public areas with high temperature and humidity (baths, saunas, swimming pools). In some cases, the fungus can live on the surface of the skin for many years as part of the saprophytic flora, without causing disease, but when provoking factors appear (wearing uncomfortable shoes, decreased immunity, impaired microcirculation in skin tissues), it leads to pronounced clinical manifestations.
Squamous epidermophyton rarely develops as a result of primary infection with a fungus, it is usually preceded by another form of pathology, for example, dyshydrotic or epidermophyton of nails. The reasons why a hyperkeratotic skin reaction develops during the life of the fungus are reliably unknown – dermatologists assume that the reactivity of the body, the level of metabolism and microcirculation in skin tissues, genetic factors play a role. Violation of keratinization processes in squamous epidermophytosis affects the approaches to the treatment of this mycosis, since a significant proportion of the pathogen is protected by a thickened stratum corneum from both systemically used antifungal drugs and externally applied agents.
In the vast majority of cases, squamous epidermophyton develops on the skin of the feet – cases of its occurrence on the palms have been described, but some researchers believe that this form is possible only against the background of severe immunodeficiency. Usually the soles and lateral surfaces of the feet are affected, the development of the disease may be preceded by other forms of mycoses – nail damage, other types of epidermophytosis. The lesion itself looks like an irregular plaque of reddish, less often purple color, not towering above the surrounding skin. The surface of the element is covered with large dirty-gray scales. In long-term cases of squamous epidermophytosis, pronounced hyperkeratotic layers form around the foci. Subjective symptoms at this stage are usually limited to moderate itching and sometimes soreness.
Hyperkeratosis significantly worsens the elastic properties of the skin, so painful cracks often form around the foci of mycosis, which can become an entrance gate for secondary infection. The course of squamous epidermophytosis is very long, sometimes it takes many months and years. Sometimes this type of disease is transformed into a dyshydrotic epidermophyton. Spontaneously or against the background of insufficient treatment, the squamous hyperkeratotic form of mycosis can turn into an erased one, which manifests itself as transient itching and peeling of the skin. Squamous epidermophytosis of this type is the most dangerous in terms of the contagiousness of the patient. Sometimes the symptoms of this condition are joined by manifestations of diseases that provoke mycosis of the skin of the foot – diabetes mellitus, trophic disorders, flat feet and a number of others.
To determine squamous epidermophytosis, the method of dermatological examination of the affected skin areas and scraping with subsequent microscopy is used. In some cases, to identify the pathogen, scraping samples are seeded on pathogenic fungi in selective nutrient media. The inspection is best performed using a Wood lamp, which allows you to determine the boundaries of the fungal lesion. You can also use a simple dermatoscopy method. When questioning a patient with squamous epidermophytosis, it turns out that the disease proceeds for a long time, the itching is moderate, in the presence of cracks of hyperkeratotic skin areas, pronounced soreness is determined. During the examination, it is possible to measure the pH of the skin, which, with squamous epidermophytosis (as with any other form of this condition), will be shifted to the alkaline side.
Scraping and its subsequent microscopy are performed by a mycologist or dermatologist to confirm the diagnosis of mycosis and subsequent more accurate diagnostic methods. Microscopy, in the presence of squamous epidermophyton, in addition to epithelial cells and keratinized scales, mycelium filaments or fungal spores are determined. However, the exact identification of the type or type of pathogen is practically impossible, therefore, for the differential diagnosis of epidermophyton from other mycoses (coccidiomycosis, trichophytia, candidiasis), the method of sowing scraping on selective nutrient media is used. Differential diagnosis of squamous epidermophytosis, in addition to other mycoses, should also be performed with psoriasis and some types of lichen.
A feature of the treatment of squamous epidermophytosis is its implementation in several stages, since the simple use of antifungal agents, both systemic and local, is unable to destroy the pathogen. Initially, it is necessary to reduce the severity of hyperkeratosis and its layers, since the fungus can be located among the horny masses, being reliably protected from blood flow (that is, from systemically used drugs) and from locally prescribed medications. To eliminate horny layers in squamous epidermophytosis, compresses are used from solutions of lactic, salicylic or fruit acids, mechanical removal. After that, you can start etiotropic (antifungal) therapy of the disease.
In some cases, the treatment of squamous epidermophytosis may be limited to long-term (up to 6 weeks) administration of local antifungal drugs – fungicidal ointments and solutions (terbinafine, clotrimazole), regular foot baths, maintaining hygiene of the skin of the feet. In case of relapse after previously carried out local treatment or with a severe course of the disease, systemically acting antifungal agents can be used. In cases where squamous epidermophyton is complicated by a secondary infection, antibiotics from the penicillin or macrolide group may be added to the therapy program.
Prognosis and prevention
Squamous epidermophytosis is characterized by a long course and a tendency to frequent recurrence, but the prognosis for recovery with proper and persistent treatment is usually favorable. In order to reduce the likelihood of relapse, in addition to the above therapeutic measures, it is necessary to treat all the patient’s shoes (and, preferably, the shoes of family members) from the inside with a weak formaldehyde solution. Shoes should be worn seasonally, excessively warm or tight shoes and boots can provoke the development of squamous epidermophytosis.
It is necessary to avoid wearing someone else’s shoes, visiting public baths, saunas and swimming pools. The administration of such institutions should also carry out regular sanitary treatment of floors, furniture and bathing accessories, identify patients with epidermophytosis among workers (bath attendants, trainers in the pool). Proper foot hygiene is extremely important: daily foot baths (preferably using household soap), replacement of socks or stockings. If squamous epidermophyton has arisen against the background of a general provoking disease, its timely therapy will contribute to the cure of skin pathology.