6 factors leading to onychomycosis

The term onychomycosis (fungus of toenails and fingernails) describes fungal infections of the nails caused by dermatophytes, non-dermatophyte molds, or yeasts. There are four clinically distinct forms of onychomycosis. Diagnosis is based on CON, microscopic examination, and histological examination. The most common treatments include systemic and local treatments, sometimes with surgical excision.

Factors leading to onychomycosis

1. Increased sweating (hyperhidrosis).
2. Insufficient blood supply to blood vessels. Violation of the structure and tone of veins, especially those of the lower limbs (typical of toenail onychomycosis).
3. age. The incidence of human disease increases with age. In 15-20% of the population, the pathology occurs between 40 and 60 years of age.
4. Internal organ diseases. Disrupts the nervous, endocrine (onychomycosis most common in patients with diabetes) or immune (immunosuppressed, especially HIV infection) systems.
5. Large nail patches, consisting of a thick nail plate and its underlying contents, can cause discomfort when wearing shoes.
6. trauma. Persistent trauma or injury to the nails without proper treatment.

disease prevalence

Onychomycosis– The most common nail disease and responsible for 50% of all cases of onychodystrophy (nail plate destruction). It affects up to 14% of the population, and the prevalence and overall incidence of the disease is increasing in older adults. The incidence of onychomycosis is also increasing in children and adolescents; onychomycosis accounts for 20% of dermatophyte infections in children.

The increased prevalence of the disease may be related to increased use of tight-fitting shoes, increased use of immunosuppressive treatments, and increased use of public locker rooms.

Nail disease often begins with tinea pedis and then spreads to the nail bed, making eradication difficult. This area is a reservoir for local recurrence or spread of infection to other areas. Up to 40% of people with toenail fungus have an associated skin infection, the most common being tinea pedis (about 30%).

Onychomycosis pathogens

In most cases, onychomycosis is caused by dermatophytes, with Trichophyton rubrum and Trichophyton interdigitale being the causative agents of the infection in 90% of cases. T. tonsurans and E. floccosum have also been recorded as pathogens.Yeast and nondermatophyte mold organisms, such as Acremonium, Aspergillus, Fusarium, Brachyphyllum, and Fusarium, are responsible for approximately 10% of cases of toenail fungus. Interestingly, Candida is the causative agent in 30% of cases of fingernail ringworm, whereas non-dermatophyte molds are not found in the affected nails.

onset

Dermatophytes possess a variety of enzymes that act as virulence factors and ensure the adhesion of the pathogen to the nails. The first stage of infection is adhesion to keratin. An inflammatory reaction occurs due to further breakdown of keratin and cascade release of mediators.The stages in the pathogenesis of fungal infections are as follows.

adhesion

The fungus overcomes several lines of host defense before hyphae begin to survive in keratinized tissue. The first is the successful adhesion of arthroconidia to the surface of keratinized tissue. Early nonspecific lines of host defense include fatty acids in sebum and colonization by competing bacteria.

Several recent studies have investigated the molecular mechanisms by which arthrospores adhere to keratinized surfaces. Dermatophytes have been shown to selectively use their proteolytic reserves during adhesion and invasion. After adhesion occurs for some time, the spores germinate and enter the next stage - invasion.

Invasion

Trauma and maceration are favorable environments for fungal penetration. The invasion of fungal germination components ends with the release of various proteases and lipases, often as various products of nutrients for the fungus.

Owner's reaction

Fungi face multiple protective barriers within the host, such as inflammatory mediators, fatty acids, and cellular immunity. The first and most important barrier is the keratinocyte, which is encountered by invading fungal elements. The functions of keratinocytes: proliferation (enhancing the shedding of keratin scales), secretion of antimicrobial peptides, and anti-inflammatory cytokines. Once the fungus penetrates deeper, more and more new non-specific mechanisms are activated to provide protection. The severity of the host inflammatory response depends on the immune status and the natural habitat of the dermatophytes involved in the invasion. The next level of defense is delayed-type hypersensitivity, caused by cell-mediated immunity.The inflammatory response associated with this hypersensitivity is associated with clinical disruption, while cell-mediated immune deficiencies can lead to chronic and recurrent fungal infections.

Although epidemiological observations suggest a genetic predisposition to fungal infections, there are no molecularly confirmed studies.

Clinical manifestations and symptoms of toenail and fingernail injuries

There are four typical clinical forms of infection. These forms may be isolated or include several clinical forms.

Distal-lateral subungual onychomycosis

It is the most common form of onychomycosis and can be caused by any of the pathogens listed above. It begins when pathogens invade the nail bed and the cuticle of the distal nail bed, causing the distal nail to appear white or brownish-yellow turbid. The infection then spreads proximally along the nail bed to the ventral aspect of the nail plate.Hyperproliferation or impaired differentiation of the nail bed due to an infectious response results in subungual hyperkeratosis, while progressive invasion of the nail plate leads to increased nail dystrophy.

proximal subungual onychomycosis

It is caused by infection of the proximal nail fold, primarily by Trichophyton rubrum and Trichophyton megnii. Clinical: The proximal part of the nail is cloudy and white or beige in color. This opacification gradually increases and involves the entire nail, eventually leading to leukonychia, proximal onycholysis, and/or destruction of the entire nail.

Patients with proximal subungual onychomycosis should be investigated for HIV infection, as this form is considered a hallmark of the disease.

White superficial onychomycosis

It occurs due to direct invasion of the dorsal plate and appears as white or dark yellow, well-defined spots on the surface of the toenail. The causative agents are usually referred to as Trichophyton metaphysica and Trichophyton mentagrophytes, although non-dermatophyte molds such as Aspergillus, Fusarium and Scopus species are also known causative agents of this form. Candida species can invade the subungual layer of the epithelium and eventually infect the nail along the entire thickness of the nail plate.

Candida onychomycosis

Nail plate lesions caused by Candida albicans are only observed in chronic mucocutaneous candidiasis, a rare disease. Usually all nails are affected. The nail plate thickens and takes on various shades of yellow-brown.

Diagnosis of onychomycosis

Although onychomycosis accounts for 50% of cases of nail dystrophy, it is recommended to obtain laboratory confirmation of the diagnosis before initiating toxic systemic antifungal agents.Study of subungual masses with KOH, culture analysis of nail plate material and subungual masses on Sabouraud dextrose agar (with or without antimicrobial additives), and staining of nail clippings using the PAS method are the most informative methods.

Learn with CON

This is the standard test for suspected onychomycosis. However, it frequently gives negative results even when clinical suspicion is high, and culture analysis of nail material in which hyphae are found during CON studies is often negative.

The most reliable way to reduce false negative results due to sampling error is to increase sample size and repeat sampling.

cultural analysis

This laboratory test determines the type of fungus and determines the presence of dermatophytes (organisms that respond to antifungal drugs).To differentiate between pathogens and contaminants, the following recommendations are made:

• If dermatophytes were isolated in culture, they were considered pathogens;
• Non-dermatophyte mold or yeast organisms are isolated in culture only if hyphae, spores or yeast cells are observed microscopically and recurrent active growth of the non-dermatophyte pathogen is observed without isolation. related.

Culture Analysis, PAS - Nail clipping staining method is the most sensitive and does not require waiting weeks for results.

Histopathological examination

On histopathological examination, hyphae are located between the layers of the nail plate, parallel to the surface. In the epidermis, spongiosis and focal parakeratosis as well as inflammatory reactions can be observed.In superficial leukomycosis, the microorganism appears on the surface of the back of the nail, displaying its unique pattern of "piercing organs" and modified hyphal elements called "leaf bites. "With candidal onychomycosis, invasion of pseudohyphae is observed. Histological examination of onychomycosis is performed using special dyes.

Differential diagnosis of onychomycosis

most likely	sometimes possible	rarely found
psoriasis leukonychia Onycholysis	congenital pachyonychia acquired leukonychia congenital leukonychia Darryl White's disease yellow nail syndrome Lichen planus	melanoma

Onychomycosis treatment

Treatment of onychomycosis depends on the severity of the nail lesions, the presence of associated tinea pedis, and the effectiveness and potential side effects of the treatment regimen. If the nail is minimally involved, topical treatment is a reasonable decision. Treatment is necessary when combined with dermatophytosis of the feet, especially in the setting of diabetes.

Topical antifungals

For patients with distal nail involvement or contraindications to systemic treatment, local treatment is recommended. However, we must remember that topical treatment with antifungal drugs alone is not effective enough.

1. Varnishes from the oxypyridone group are gaining in popularity, applied once daily for 49 weeks, with about 40% of patients achieving mycological cure and 5% of cases of mild or moderate onychomycosis caused by dermatophytes achieving nail cleansing (clinical cure).Although much less effective than systemic antifungals, topical use of this drug avoids the risk of drug interactions.
2. Another drug was specially developed in the form of nail polish to be used twice a week. It is a representative of the new antifungal drug morpholine derivatives, which is effective against yeast, dermatophytes and molds that cause onychomycosis.This product may have a higher mycological cure rate than previous varnishes; however, controlled studies are needed to determine a statistically significant difference.

Oral antifungal medications

Systemic antifungals are needed if onychomycosis involves stromal areas or requires a shorter course of treatment or a higher chance of clearance and cure. When selecting an antifungal agent, the etiology of the pathogen, potential side effects, and the risk of drug interactions for each patient should first be considered.

1. Allylamine drugs have inhibitory and fungicidal effects on dermatophytes and Aspergillus, but are less effective on Scopus genus. This product is not recommended for candidal onychomycosis as its effectiveness against Candida species varies.For most toenail injections, a standard dose of 6 weeks is effective, while toenail injections require at least 12 weeks. Most side effects are related to digestive problems and include diarrhea, nausea, taste changes, and elevated liver enzymes.Data show that a 3-month continuous dosing regimen is currently the most effective systemic therapy for the treatment of toenail onychomycosis. Clinical cure rates in various studies are around 50%, but rates are higher in patients over 65 years of age.
2. An azole drug with fungistatic activity against dermatophytes and non-dermatophyte mold and yeast organisms. Safe and effective treatment options include daily pulse dosing one week per month or continuous daily dosing, both of which require two months or two cycles of treatment for nails and at least three months for toenail lesionsor three pulse treatments.For children, drug doses are given individually based on body weight. Although the drug has a broader spectrum of action than its predecessor, studies have shown that it has significantly lower cure rates and higher relapse rates.

   Liver enzyme levels increased during treatment in less than 0. 5% of patients and returned to normal within 12 weeks of stopping treatment.

3. A drug with fungicidal activity against dermatophytes, certain non-dermatophyte molds, and Candida spp. This medication is usually taken once a week for 3 to 12 months.

   There are no clear standards for laboratory monitoring of patients receiving the above drugs. It makes sense to perform a complete blood count and liver function tests before treatment and 6 weeks after starting treatment.

4. Due to the long course of treatment, potential side effects, drug-drug interactions, and relatively low cure rates, drugs in the grisan group are no longer considered standard treatments for onychomycosis.

Combination treatment regimens may result in higher clearance than systemic or local treatments alone. Ingestion of allylamine drugs and application of morpholine varnish resulted in clinical cure with negative mycological testing in approximately 60% of patients compared with 45% of patients receiving systemic allylamine antifungals alone. However, another study showed no additional benefit when combining systemic allylamine drugs with oxypyridone drug solutions.

Other medicines

The in vitro bactericidal activity of thymol, camphor, menthol, and oil of lemon eucalyptus suggests the potential of additional therapeutic strategies for the treatment of onychomycosis. An alcoholic solution of thymol can be applied in the form of drops on the nail plate and undernail. It can be cured in individual cases with topical nail preparations containing thymol.

Surgery

Final treatment options for refractory cases include surgical nail removal with urea. To remove more fragments from the affected nail, special pliers are needed.

Many doctors believe that the primary and primary method of treating onychomycosis is mechanical nail removal. In most cases, surgical removal of the affected nail is recommended, and in a few cases, removal with a keratolysis patch is recommended.

Traditional ways to fight onychomycosis

Although there are a large number of different folk remedies for getting rid of nail fungus, dermatologists do not recommend choosing this treatment option and starting with a "home diagnosis". It is wiser to start treatment with local medicines that have been clinically tested and shown to be effective.

Course and prognosis

Signs of a poor prognosis are pain due to thickening of the nail plate, secondary bacterial infection, and diabetes. The most beneficial way to reduce the likelihood of recurrence is to combine treatments. Treatment for onychomycosis is a long road, and full recovery is not always possible. But don’t forget that the effectiveness of systemic treatment is as high as 80%.

prevention

Prevention includessome events, you can significantly reduce the percentage of onychomycosis infections and reduce the likelihood of recurrence.

1. Disinfection of personal and public items.
2. Systematically disinfect shoes.
3. Treat feet, hands, folds (under favorable conditions - the most preferred location) with local antifungal medicines according to the advice of a dermatologist.
4. If onychomycosis is diagnosed, you will need to see your doctor for monitoring every 6 weeks and after completing systemic treatment.
5. If possible, your nail plate should be disinfected every time you visit your doctor.

in conclusion

Onychomycosis (fungus of the fingernails and toenails) is an infection caused by a variety of fungi. This disease affects the nail plates of the fingers or toes. When making a diagnosis, check all skin and nails and rule out other conditions that mimic onychomycosis. If there is any doubt about the diagnosis, it must be confirmed by culture (preferably) or by histological examination of nail clippings followed by staining.Treatment includes surgical excision, topical and general medical therapy. Treatment of onychomycosis is a lengthy process that can last for years, so you shouldn't expect "one pill" to make you better. If you suspect onychomycosis, see a specialist to confirm the diagnosis and develop an individualized treatment plan.