Fungal infection of the toenails or onychomycosis is an infectious disease and a fairly common pathology.The prevalence of toenail lesions ranges from 18% to 45% in various countries around the world.Onychomycosis commonly occurs in the elderly, cancer patients, and patients with diabetes, Kaposi's sarcoma, and ichthyosis.
Onychomycosis is more than just a cosmetic problem.It poses a serious threat to the human body, since the products of the life activity of the fungus (sodium, viomelin, antibiotic substances and penicillin) lead to the long-term persistence of the affected nails and can lead to the development of liver disease, drug-induced venom dermatosis or even Lyell's syndrome.
etiology and epidemiology
The causative agents of onychomycosis are represented by three types of fungi:
- Dermatophytes (up to 95%) - Trichophyton rubrum (causes damage to the nails and skin of the feet and hands), Trichophyton mentagrophytes (affects the nails of the first and fifth toes and the skin of 3-4 interdigital folds), Epidermophyton floccosum (the nails of the first and fifth toes);
- Yeast fungi (up to 4%) - Candida spp.(First affecting the skin around the nail, then penetrating the nail plate itself);
- Molds (up to 1%) - Fusarium and Alternaria (most common in immunodeficient states).
Isolated onychomycosis is rare; more commonly, lesions occur simultaneously on the skin of the feet, scalp, and smooth skin.
Infection occurs through household items: bathroom rugs, slippers, towels, manicure accessories; and when visiting bathrooms, saunas or swimming pools.Men are more susceptible to this pathology than women.Most adults suffer from onychomycosis; in children, cases of onychomycosis are rare.
High-risk groups include bathhouse attendants, military personnel, athletes, people who frequent bathhouses and saunas, and miners.
The source of infection is the skin on the infected person's feet; sometimes the entire family is affected.
Pathogenesis
Onychomycosis is a source of fungal infection that can lead to allergies in the body.Additionally, mushrooms release substances that are toxic to humans.
Predisposing factors for infection are injuries to the skin and nails of the feet when the toes are squeezed by tight shoes; a moist and warm environment caused by some inferior shoes made of unnatural materials; serious illness, immunodeficiency, and old age.
disease symptoms
Onychomycosis is divided into four forms based on differences in symptoms:
- Distal lateral (subungual) onychomycosisThe most common.The causative agents are Trichophyton rubrum, Candida and, rarely, mold.With this type of lesion, the fungus in the nail bed enters from the skin through the free edge of the nail and spreads toward the matrix.In this condition, the nail plate gradually moves away from the nail bed and takes on a yellowish color due to hyperkeratosis.The nail plate may become thickened, and bacterial contamination can cause nails to take on a variety of colors, from green to dirty brown.
- White superficial onychomycosisMost commonly caused by Trichophyton mentagrophytes, it causes white spots to form on the surface of the nail plate; these spots will coalesce as the process progresses.This type of onychomycosis occurs in older patients with toe deformities in which one toe covers an adjacent toe.The nail plate is malnourished, broken, and gray or brown, but the matrix and nail bed epithelium are not affected, and there is no inflammation in the skin.
- proximal subungual onychomycosisThe rarest type, in which the pathogen (most commonly Trichophyton rubrum) penetrates the nail plate from the skin or periungual folds and then spreads along the nail plate and reaches the stroma and distal portions of the nail plate.As a result, extensive detachment of the deck was observed.With secondary bacterial contamination, the nail plate will become discolored.
- total dystrophic onychomycosisDevelopment of distal lateral or, less commonly, proximal subungual complications also occurs in chronic subcutaneous candidiasis.In this form, the entire nail is affected by complete destruction; the nail fold is either missing or pathologically thickened, preventing the formation of a normal nail plate.
All onychomycosis should be differentiated from skin diseases such as psoriasis, eczema, and lichen planus.To confirm the diagnosis, microscopic examination of pathological material from the diseased tissue and culture of the pathogen on special identification media are required.
Treatment of onychomycosis
When prescribing treatment for patients with onychomycosis, several factors must be taken into account: the type of pathogen, the prevalence of the infectious process, the general condition of the patient and his financial capabilities.
- Topical medications are commonly used to treat distal and lateral subungual onychomycosis when no more than 3 nails are affected and in patients in whom the use of tablet-type antifungals is contraindicated.The most effective topical preparations include creams and varnishes.They are often used in combination to achieve faster treatment results.This preparation contains a high concentration of active ingredients; they work effectively on the nail plate surface but are not always able to penetrate into the nail bed, where the most persistent fungi are located.In this case, the affected nail plate can be removed surgically or with the use of special chemicals (keratolytic agents) and topical treatment can be continued.The reason this method is inconvenient is simply that the process is longer, as it requires careful adherence to the treatment regimen throughout the entire process of healthy nail plate growth.In this case, ointment should be used every day and varnish only once a week.
- Systemic treatment is more effective and reliable for the treatment of onychomycosis; it is used when local treatment is ineffective.Indications for systemic use are distal lateral and proximal subungual onychomycoses and advanced stages of panonychomycosis.
The selection of agents for systemic treatment must be rational, taking into account the pharmacokinetics, spectrum of action, and antifungal activity of each agent.It should not be forgotten that any drug can provide significant therapeutic effects if adequately prescribed.