Dermatofitiya

Description:

Dermatofitiya is the infectious diseases caused by dermatophytes. The attention which is a problem attracts now, is explained by extreme prevalence of an infection and the remaining problems of its diagnosis and treatment.

Dermatofitiya reasons:

Dermatophytes call mold mushrooms - the Arthodermataceae family ascomycetes (Onygenales order) relating to three childbirth - Epidermophyton, Microsporum and Trichophyton. In total 43 types of dermatophytes, from them - 30 activators of a dermatofitiya are known.

The main causative agents of mycoses are, as occurrence, T. rubrum, T. mentagrophytes, M. canis.

Dermatophytes call geofilny, zoophilous or anthropophilous depending on their usual habitat - the soil, an organism of animals or the person. Members of all three groups can cause diseases of the person, but their various natural tanks define epidemiological features - an activator source, prevalence and geography of areas.

Though many geofilny dermatophytes can cause an infection both in animals, and in people, the most usual, the native habitat of these mushrooms is the soil. Members of zoophilous and anthropophilous groups came as consider, from these and other saprophytes inhabiting the soil capable to destroy a keratin. Zoophilous organisms sporadic can be transferred to people if have affinity to a keratin of the person. Transfer happens at direct contact with the infected animal, or through objects on which wool and skin scales of these animals get. Often infections arise in rural areas, but the role of domestic animals (is especially big especially at an infection of M. canis now). Many members of zoophilous group are called according to owners animals. The general epidemiological characteristic of zoonotic and antroponozny dermatofitiya - high contageousness. Dermatofitiya, perhaps, the only contagious infection among all mycoses of the person.

The nature of infections caused by anthropophilous dermatophytes is, as a rule, epidemic. The main gain of incidence is provided with anthropophilous types. Now anthropophilous dermatophytes can be found in 20% of all population, and the infections caused by them are the most widespread mycoses. According to our epidemiological research, growth of incidence of a dermatofitiya is observed.

Pathogeny:

All dermatophytes have keratinolitichesky activity, i.e. are capable to decompose a keratin of animals and/or the person. Activity кератиназ and in general proteolytic enzymes is considered a basis of pathogenic properties of dermatophytes. Keratinaza are capable to decompose not only a keratin, but also other animal protein, including collagen and elastin. Activity кератиназ is not identical at different dermatophytes. T. mentagrophytes very moderate - T. rubrum differs in the highest activity. To ability to decompose different types of a keratin in general there corresponds localization of a dermatophyte infection. So, E. floccosum - a view with low keratinolitichesky activity - does not affect hair.

Implementation of colony of the activator in epidermis is provided with both keratinolitichesky activity, and growth of hyphas. As mold mushrooms, dermatophytes have the specialized device for the directed growth of a hypha. It is sent to points of the smallest resistance, as a rule - to joints between adjacent cells. The penetrating hyphas of dermatophytes traditionally consider special bodies perforators. Still not clearly, whose role in invasive process is more important - кератиназ or pressure of the directed growth.

Depth of advance of fungal colony in epidermis is limited. At skin infections dermatophytes seldom get more deeply than a granular layer where they are met by natural and specific factors of protection. Thus, the dermatophyte infection covers only lifeless, keratosic fabrics.

The available data on factors of protection of a macroorganism at a dermatofitiya call in question the point of view of some authors that at this infection there is a limfogematogenny distribution of the activator or its bedding in not keratosic fabrics washed by blood. Deep forms of a dermatofitiya are described at patients with the expressed deficit of one or several factors of resistance.

Dermatofitiya symptoms:

The principle of localization is put in a basis of the foreign classification of mycoses accepted in MKB-10. This classification is convenient from the practical point of view, however does not consider etiological features of a dermatofitiya in some localizations. At the same time options of an etiology define epidemiological characteristics and the need for the relevant activities, and also features of laboratory diagnosis and treatment. In particular, representatives of the sorts Microsporum and Trichophyton have unequal sensitivity to some antimycotics.

The standard classification long time was offered by N. D. Sheklakov in 1976. In our opinion, a reasonable and acceptable compromise is use of classification of MKB with specification, if necessary, of an etiology of the activator or its equivalent. For example: the dermatofitiya of smooth skin (tinea corporis B35.4) caused by T. rubrum (Xing. tinea of smooth skin). Or: dermatofitiya of a pilar part of the head (B35.0 favus/microsporia/trichophytosis).

The term "dermatomycoses" for which sometimes try to change the common name of a dermatofitiya is inappropriate and cannot serve as a dermatofitiya equivalent.

Dermatomycoses are fungal infections of skin in general, i.e. both candidiasis, and multi-colored deprive, and many mold mycoses.

Dermatofitiya of a pilar part of the head
Abroad allocate the following kliniko-etiological tinea capitis forms:
1) ektotriks-infection. Microsporum spp is caused. (anthropozoonotic microsporia of a pilar part of the head);
2) endotriks-infection. Trichophyton spp is caused. (antroponozny trichophytosis of a pilar part of the head);
3) favus (scab). T. shoenleinii is caused;
4) керион (infiltrative and suppurative dermatofitiya).

The most widespread of the listed infections is the microsporia. The main activator of a dermatofitiya of a pilar part of the head in Eastern Europe is Microsporum canis. The number of the registered microsporia cases in recent years made up to 100 thousand a year. It is necessary to recognize occurrence of the activators of an antroponozny microsporia (M. ferrugineum) and trichophytosis (T. violaceum) extended in the Far East and in Central Asia sporadic.

The classical picture of a microsporia is usually presented by one or several roundish centers with quite clear boundary, from 2 to 5 cm in the diameter. Hair from the centers dim, fragile, light gray color, at the basis are dressed in a white cover. The hair loss over the surface of skin explains that the centers are represented cut, corresponding to the name "cutting deprive". Skin in the center is slightly hyperemic and edematous, covered with grayish small scales. The specified clinical picture corresponds to the name "herpes of gray spots".

The centers are characteristic of a trichophytosis of a pilar part of the head multiple isolated small (to 2 cm). Typically oblamyvany a hair at the level of skin, leaving пенек in the form of the black point which is looking out of the mouth of a follicle ("deprive of black points").

The classical picture of a favus is characterized by existence скутул (scutula, lat. a guard) - crusts of dirty-gray or yellow color. The created skutula represents a dry saucer-shaped crust which of center there is a hair. Each skutula consists of the mass of the hyphas which are stuck together by exudate i.e. in essence is colony of a mushroom. In the started cases of a skutula merge, covering the most part of the head. The continuous crust at a favus reminds bee cells what the Latin name of a disease is obliged to. At a widespread favus from crusts proceeds unpleasant, "mouse" (granary, cat's) began to smell. Now the favus practically does not meet in Russia.

The expressed inflammation with dominance of pustules and formation of large educations - kerion is characteristic of an infiltrative and suppurative form of a microsporia and a trichophytosis. Kerion - the painful dense center of an erythema and infiltration - has the convex form, looks bright red or cyanotic, with a clear boundary and a hilly surface, is covered with the numerous pustules and erosion which are often hidden under is purulent - hemorrhagic crusts. Expanded mouths of follicles from which when pressing yellow pus is emitted are characteristic. The similar picture is compared to honey cells (kerion). Kerion often is followed by the general phenomena - fever, an indisposition, a headache. Painful regional lymphadenitis (usually zadnesheyny or zaushny nodes) develops.

Dermatofitiya of nails
Onychomycoses strike not less than 5-10% of the population, and over the last 10 years incidence grew by 2,5 times. Onychomycoses on feet meet by 3-7 times more often than on brushes. Dermatophytes are considered as the main activators of an onychomycosis in general. About 70-90% of all fungal infections of nails fall to their share. Any of dermatophytes, but most often two look can be the activator of an onychomycosis: T. rubrum and T. mentagrophytes var. interdigitale. T. rubrum - the main activator of onychomycoses in general.

Allocate three main clinical forms of an onychomycosis:  distal and lateral, proximal and superficial, depending on the place of implementation of the activator. Most often the distal form meets. At the same time elements of a mushroom get into a nail from the affected skin in the field of the broken connection of the distal (free) end of a nail and skin. The infection extends to a nail root, and its advance requires mushroom growth rate superiority over the speed of natural growth of a nail in the opposite direction. Growth of a nail is slowed down with age (to 50% after 65-70 years) in this connection onychomycoses and prevail at elderly people. Clinical manifestations of a distal form - the loss of transparency of a nail plate (онихолизис) which is shown as whitish or maculas lutea in the thickness of a nail, and a hyponychial hyperkeratosis at which the nail looks reinforced. At a rare proximal form mushrooms get via the proximal roller of a nail. White or maculas lutea appear in the thickness of a nail at its root. At a superficial form the onychomycosis is presented by spots on a surface of a nail plate.

The average settlement duration of a disease now (in the presence of tens of effective antimycotics) makes 20 years, and by results of poll of patients of middle age - about 10 years. It is a lot of for a contagious disease.

Dermatofitiya of brushes and feet
Mycoses of feet are widespread everywhere and meet more often than any other mycoses of skin. The main causative agent of mycosis of feet is T. rubrum, much less often mycosis of feet cause T. mentagrophytes var. interdigitale, is even more rare - other dermatophytes. The mycoses of feet caused by T. rubrum and T. mentagrophytes have features of epidemiology and a clinical picture. At the same time the options of mycosis of feet typical for one activator, but caused by another are possible.

Infection with the mycosis of feet caused by T. rubrum (a tinea of feet) occurs in a family, at direct contact with the patient more often, and also through footwear, clothes or the general objects of use. The infection differs in a chronic current, defeat of both feet, frequent distribution on smooth skin and nail plates. At a long current involvement of skin of palms, as a rule, of the right (working) brush - a syndrome of "two feet and one brush" is characteristic (tinea pedum et manuum). Usually T. rubrum causes chronic squamous гиперкератотическую a form of mycosis of feet, so-called "mokasinovy type". At this form the bottom surface of foot is surprised. In the struck area the easy erythema, the moderated or expressed peeling, and in some cases - and a thick layer of a hyperkeratosis is noted. The hyperkeratosis is most expressed in the points bearing the greatest loading. When the center continuous also covers all surface of a sole, foot becomes as if the erythema dressed in a layer and a hyperkeratosis like moccasins. The disease, as a rule, is not followed by subjective feelings. Sometimes manifestations of a tinea of feet are minimum, presented by an easy peeling and cracks on a sole - the so-called erased form.

Infection with the mycosis of feet caused by T. mentagrophytes (an epidermophitia of feet) occurs in places of public use more often - gyms, baths, saunas, pools. At an epidermophitia of feet the interdigital form is usually observed. In the 3rd, 4th, sometimes in the 1st interdigital fold there is a crack at the edges bordered with white strips of matserirovanny epidermis against the background of a surrounding erythema. These phenomena can be followed by an unpleasant smell (especially at accession of a consecutive bacterial infection) and are, as a rule, painful. In some cases surrounding skin and nails of the next fingers of foot is surprised (I and V). T. mentagrophytes is a strong sensitizer and sometimes causes a vesicular form of mycosis of feet. In this case on fingers, in interdigital folds, on the arch and side surfaces of foot small bubbles are formed. In rare instances they merge, forming bubbles (a violent form).

Dermatofitiya of smooth skin and large folds
Dermatofitiya of smooth skin meet less than mycoses of feet or onychomycoses. Any dermatophytes can cause damages of smooth skin. As a rule, in Russia they are called T. rubrum (a tinea of smooth skin) or M. canis (a microsporia of smooth skin). Also zoonotic mycoses of smooth skin caused by more rare species of dermatophytes meet.

The centers of mycosis of smooth skin have characteristics - the ring-shaped eccentric growth and scalloped outlines. Because in the infected skin phases of implementation of a mushroom to new sites, inflammatory reaction and its permission gradually are replaced, growth of the centers from the center to the periphery looks as the extending ring. The ring is formed by the roller of an erythema and infiltration, in the center it the peeling is noted. At merge of several ring-shaped centers one big center with polycyclic scalloped outlines is formed. For a tinea, as a rule, striking adults, the widespread centers with the moderate phenomena of an erythema are characteristic, at the same time it is possible to find in the patient also mycosis of feet or brushes, an onychomycosis. The small monetovidny centers on the closed sites of skin are characteristic of the microsporia striking generally the children catching from domestic animals, it is frequent - the centers of a microsporia of a pilar part of the head.

In certain cases doctors, without having distinguished mycosis of smooth skin, appoint corticosteroid ointments to the center of an erythema and infiltration. At the same time the inflammatory phenomena abate, and mycosis takes the erased form (so-called tinea incognito).

The mycoses of large folds caused by dermatophytes also keep characteristic features: the peripheral roller, permission in the center and polycyclic outlines. The most typical localization - inguinal folds and the interior of a hip. The main activator of an inguinal dermatofitiya is T. rubrum (an inguinal tinea) now. The traditional designation tinea cruris in domestic literature was the inguinal epidermophitia according to the name of the activator - E. floccosum (the old name - E. inguinale).

Diagnosis:

The basic principle of laboratory diagnosis of a dermatofitiya - detection of a mycelium of the activator in pathological material. It is enough for confirmation of the diagnosis and an initiation of treatment. Pathological material: skin scales, hair, fragments of a nail plate, before a mikroskopirovaniye subject to "enlightenment", i.e. processing by alkali solution. It allows to dissolve horn structures and to leave under review only the mass of a mushroom. The diagnosis is confirmed if in drug threads of a mycelium or a chain конидиев are visible. In laboratory diagnosis of a dermatofitiya of a pilar part of the head consider also an arrangement of elements of a mushroom concerning a hair core. If disputes are located outside (it is characteristic of types of Microsporum), such type of defeat is called эктотрикс and if inside - that эндотрикс (it is characteristic of types of Trichophyton). Definition of an etiology and identification of dermatophytes are carried out on morphological features after allocation of culture. If necessary additional tests are carried out (ureazny activity, a chromogenesis on special environments, the need for nutritious additives, etc.). For bystry diagnosis of a microsporia also cold light lamp of Wood in which beams mushroom elements in the centers of a microsporia give a light green luminescence is used.

Treatment of a dermatofitiya:

In treatment of a dermatofitiya all system antifungal means for intake and practically all local antimycotics and antiseptic agents can be used.

From system drugs affect only dermatophytes or are allowed for use only at a dermatofitiya griseofulvin and тербинафин. Drugs with more broad spectrum of activity belong to the class of azoles (imidazoles - кетоконазол, triazoles - флуконазол, итраконазол). The list of local antimycotics contains tens of different connections and dosage forms and constantly is replenished.

Among modern antimycotics тербинафин differs in the highest activity concerning dermatofitiya activators. The minimum overwhelming concentration of a terbinafin average about 0,005 mg/l that on orders below concentration of other antimycotics, in particular, azoles. Therefore already many years тербинафин it is considered the standard and drug of the choice in treatment of a dermatofitiya.

Topical treatment of the majority of forms of a dermatofitiya of a pilar part of the head is inefficient. Therefore before emergence of peroral system antimycotics of sick children isolated not to infect other members of children's collective, and in treatment applied various methods of an epilation. The main method of treatment of a dermatofitiya of a pilar part of the head is system therapy. In treatment can be used griseofulvin, тербинафин, итраконазол and флуконазол. Griseofulvin remains the standard of treatment of dermatofitiya of a pilar part of the head so far.

Terbinafin is more effective, than griseofulvin in general, however is also less active concerning M. canis. It is shown in discrepancy of domestic and foreign recommendations as in Western Europe and the USA mean a trichophytosis by tinea capitis more often, and in Russia - a microsporia. In particular, domestic authors noted need of increase in a dose at a microsporia for 50% from recommended. On their observations, effective daily doses of a terbinafin at a microsporia are: children with body weight to 20 kg have 94 mg/days (3/4 125 mg of a tablet); to 40 kg - 187 mg/days (1,5 125 mg of a tablet); more than 40 kg - 250 mg/days. Adult appoint doses of 7 mg/kg, no more than 500 mg/days. Treatment duration - 6-12 weeks.

In treatment of a dermatofitiya of nails also use local and system therapy or their combination - a combination therapy. Local therapy is applicable generally only at a superficial form, the initial phenomena of a distal form or damages of single nails. In other cases system therapy is more effective. Modern local means for treatment of onychomycoses include antifungal nail varnishes. System therapy includes drugs of a terbinafin, итраконазол and флуконазол.

Treatment duration any drug depends on a clinical form of an onychomycosis, prevalence of defeat, degree of a hyponychial hyperkeratosis, the affected nail and age of the patient. For calculation of duration the KIOTOS special index offered by us is used now. The combination therapy can be appointed when only system therapy is not enough or it has big duration. Our experience of a combination therapy with use of a terbinafin includes its use by the shortened courses and in the discontinuous scheme, in combination with antifungal nail varnishes.

In treatment of a dermatofitiya of feet and brushes use both local, and system antifungal means. Outside therapy is most effective at the erased and interdigital forms of mycosis of feet. Modern antimycotics for topical administration include creams, aerosols, ointments. If these means are unavailable, use local antiseptic agents. Duration of treatment makes of two weeks when using modern drugs to four - when using traditional means. At chronic squamous гиперкератотической a form of mycosis of feet, involvement of brushes or smooth skin, damage of nails local therapy is often doomed to failure. In these cases appoint system drugs - тербинафин - on 250 mg a day within not less than two weeks, итраконазол - on 200 mg twice a day within one week. At damage of nails terms of therapy last. System therapy is shown also at the ostrovospalitelny phenomena, vezikulo-violent forms of an infection. Outwardly in these cases use lotions, solutions of antiseptic agents, aerosols, and also the combined means combining corticosteroid hormones and antimycotics. The desensibilizing therapy is shown.

Outside therapy at damages of smooth skin is shown at the isolated damage of smooth skin. At damage of vellus hair, a deep and infiltrative and suppurative dermatofitiya, tinea incognito system therapy is shown. We recommend it also at localization of the centers on a face, and at a widespread tinea (though at them also nails are, as a rule, affected).

Outside antifungal drugs use in the form of creams or ointments; use of an aerosol is possible. The same drugs, as for treatment of mycosis of feet are used. Duration of outside therapy makes 2-4 weeks or before disappearance of clinical manifestations and 1 more week after that. Drugs it is necessary to inflict on the center defeats and on 2-3 cm of a knaruzha from its edges.

At simultaneous defeat of a pilar part of the head or nails system therapy is conducted according to the corresponding schemes. In other cases at system therapy appoint тербинафин on 250 mg/days during 2-4 weeks (depending on the activator), or итраконазол 1 cycle pulse therapy (on 200 mg twice a day during 1 week). Similar schemes use at an inguinal dermatofitiya.