ONYCHOMYCOSIS

     According to WHO, 40% of drugs that are prescribed to patients for various indications, are not scientifically proven effectiveness. It is especially clearly manifested in the treatment of certain fungal infections. Contrary to the claims rather annoying advertising, currently there are no sufficiently effective antifungal agents, and the available offer a "bouquet" of side effects. This state of affairs determined the inclusion of the WHO task of developing effective antifungal agents for the fourth place in the list of the top medicinal priorities for the current century, immediately after the same objectives with respect to hypertension, multiple sclerosis and rheumatic diseases. But something should be treated! And how to do it with minimal risk and maximum success?

     Onychomycosis (from the Greek words "onihos" – nail + "mikos" – fungus) is a specific lesion of nails, caused by various pathogenic fungi. Synonyms – nail fungus. In practice, this pathology usually develops secondarily, against fungal infection of the skin lesions of fingers, interdigital folds, palms and soles. According to statistics, the incidence of this condition covers about 10% of the population, and the overall incidence over the past 10 years has grown to more than 2 times. In patients with onychomycosis of the feet hit the nails in 80%. At this location is used more and the term "onychomycosis of feet". The disease usually begins between the ages of 20-50 years, and dominated by men. Special studies indicate that adults suffer from onychomycosis in more than 30 times more likely than children and adolescents. If people under 18 years it occurs in 2.6% of cases, 90% of the patients are elderly people [1, 2].

     Risk factors for onychomycosis, in addition to the presence of a patient with chronic fungal infection generally include family history, age, material status of the patient and his level of culture, the presence of immunosuppressive diseases (diabetes, general weakness, etc.), visiting the public baths and the wearing of tight shoes. In addition, its appearance contributes to injury, frequent skin maceration, a tendency to hyperhidrosis of feet and hands (excessive sweating) that are available peripheral circulatory disorders [3].

The increasing prevalence of fungal infection due to the fact that many people infected by nail fungus, avoid treatment and do not seek medical attention. Today, the typical patient has a medical history of onychomycosis, which can last for years. Untreated fungal infection leads to other people in the first place - the family members. Infection occurs through contact with pathogenic fungi that are commonly found in skin cells and bits of nail plates ill. Often, patients are trying to get rid of the fungus on their own with the help of external funds or various "folk methods". But many studies have shown that treatment of onychomycosis in most cases proves to be ineffective [4, 5].

     Clinical manifestations. In practice, to distinguish different clinical forms of onychomycosis (peripheral, proximal, degenerative, etc.), which to some extent reflect the stage of the disease. It is to some extent depending on the virulence of the fungus causing the disease and the susceptibility of the patient. Causative agents of onychomycosis are dermatophytes often, yeast-like and mold fungi. The most common Trichophyton rubrum (Tr. rubrum), which infects the nails down three times more likely than the hands. Slightly inferior to him Candida spec. and Tr. mentagrophytes var. interdigitale (Tr. interdigitale), who defeat only the nails of the feet. Onychomycosis is less common due to Tr. violaseum and Tr. tonsurans. Even more rarely, a patient is allocated other fungi (zoophile Trichophytones, Tr. Schonlein, mold Aspergillus, Scopulariopsis, etc.).

     Externally the disease appears thickening, loosening and brittle nails. Infected nails are deformed, fade, yellow, thicken, and then crumble (Fig. 1). Over time fungal infection takes severe. And if the initial stages of onychomycosis, as a rule, lead to only a cosmetic defect, then over time the patient has difficulty in caring for the nails, wearing shoes. Patients appear pain, discomfort when walking, which to varying degrees restrict his activity and mobility. A number of special studies have shown that patients of onychomycosis is sharply reduced quality of life - a set of emotional, physical and social determinants of self-esteem and a sense of health. Patients become suspiciousness, avoid or take off one's shoes to undress in front of others (such as beach and pool), have experience because others will notice the condition of their nails [1, 4, 6].

Diagnosis is established on the basis of clinical and laboratory data (detection of mycelial filaments and spores into scrapes with the low-lying parts of the nail, subungual mass culture and isolation of the fungus).

Effective treatment of onychomycosis of feet, whose goal is to treat the agent and the normalization of the appearance of the nail, is, in most cases, very serious difficulties. As a general rule, the specific therapeutic tactics depends on the stage (clinical type) of onychomycosis, which account for its prevalence and degree of damage to the nail.

     Medications for external use are effective only in the initial stages of the disease. Experience shows that with the involvement in the pathological process the nail plate in most cases requires systemic antifungal therapy. Basically, this is due to the fact that external funds are not penetrate in those places where concealed germ – the nail plate. At the same time they can be used with systemic antifungal drugs to prevent recurrence of nail infections. The most promising for this, depending on the stage and form of onychomycosis, as well as the characteristics of the treatment, are medications ciclopirox (e.g. cream and solution Batrafen) bifonazol (e.g. Bifonal or Micospor), clotrimazole (e.g., Candid-B or Clotrisal), imidazole derivatives, zinc pyrithione, etc.

     Several years ago, medical treatment of onychomycosis has been limited by local agents and two not very efficient medications with systemic effects: griseofulvin and ketoconazole. Their use made it a high relapse rate – up to 70-85%, required a very long time-bound modes of treatment (10-18 months), constant laboratory monitoring, and perhaps most importantly gave numerous side effects. The development of antifungal agents for systemic use of new generation (itraconazole and terbinafine derivatives) has revolutionized the treatment of onychomycosis due to a very substantial reduction in side effects in their application, as well as for reducing the number of drug interactions. They offer shorter treatment regimens, significantly greater efficacy and fewer side effects. Fluconazole is an alternative to drugs mentioned, and in the very near future is expected to appear on the market its new high-performance derivatives. The effectiveness of a new generation of antifungal agents based on their ability to directly penetrate the nail plate at the required concentration, which is usually just a few days of starting treatment. Some studies in recent years have shown the effectiveness of primary treatment of onychomycosis in different groups of patients using itraconazole (e.g., Orungal) and terbinafine at 35-50-70% [2, 3, 7]. In table 1 summarizes the recommendations for the use of a new generation of systemic antifungal drugs for onychomycosis and given their trade names.

     In some cases further reducing the frequency of drug side effects as well as reducing the timing of antifungal drug can be achieved by combined use of antifungal agents (systemic and local) and removal of the nail. Last performed by chemical or mechanical removal. However, in contrast to the relatively recently, when such a procedure was necessary in most cases, it is now considered to be justified by very thick nails or in patients intolerant of drugs. A number of researchers recommend that in some cases to reduce the cost of the total cost of treatment [4, 7].

     However it is worth remembering that because recurrence of fungal infection, even with the newest and most effective of drugs remains high, the decision to treatment must be made with a clear patient’s understanding of possible side effects, the cost of such a course of therapy and the risk of recurrence onychomycosis.

Fig. 1. Various forms and stages of onychomycosis of feet.

References.

1. Faergemann J., Baran R. Epidemiology, clinical presentation and diagnosis of onychomycosis // Br J Dermatol. – 2003. – V.149, Suppl 65. – P.1-4.
2. Crawford F., Young P., Godfrey C. et al. Oral treatments for toenail onychomycosis: a systematic review // Arch Dermatol. – 2002. – V.138, № 6. – P. 811-816.
3. Iorizzo M., Piraccini B.M., Rech G., Tosti A. Treatment of onychomycosis with oral antifungal agents // Expert Opinion on Drug Delivery. – V.2, № 3, 2005. – P.435-440.
4. Cribier B.J., Paul C. Long-term efficacy of antifungals in toenail onychomycosis: a critical review // Br J Dermatol. – 2001. – V.145, № 3. – P.446-452.
5. Nandedkar-Thomas M.A., Scher R.K. An update on disorders of the nails // J Am Acad Dermatol. – 2005. – V.52, № 5. – P.877-887.
6. Warshaw E.M., Bowman T., Bodman M.A. et al. Satisfaction with onychomycosis treatment. Pulse versus continuous dosing // J Am Podiatr Med Assoc. – 2003. – V.93, № 5. – P.373-379.
7. Cohen A.D., Medvesovsky E., Shalev R. et al. An independent comparison of terbinafine and itraconazole in the treatment of toenail onychomycosis // J Dermatolog Treat. – 2003. – V.14, № 4. – P.237-242.