Epidermophytosis of the Large Skin Folds,

or Epidermophytosis (Tinea) Inguinalis, or Tinea Cruris

(Epidermophytia Plicarum, seu Epidermophytia Inguinalis)

Etiology. The causative agent is the fungus Epidermophyton inguinale Sabouraud (E. ftoccosum).

Epidemiology. Contamination occurs in public baths and from using a common bath and sponges. The causative agent may be conveyed to humans by means of bed-clothes, oil-cloth, bed-pans, thermometers, towels and sponges shared with a sick individual.

Pathogenesis. Increased sweating in the inguinofemoral folds and axillae, particularly in obese individuals and in those with diabetes mellitus, moistening of the skin with compresses are factors which facilitate the development of the disease. The disease is encountered most frequently among men; children and adolescents rarely have it.

Clinical picture and course. The lesions are localized in the femoroscrotal folds, on the medial surface of the thighs, on the pubis, and in the axillae. In some cases the pathological process may spread to the skin on the chest, abdomen (between the skin folds in obese individuals), under the mammary glands in females, etc. Red inflammatory, scaling spots the size of a lentil appear first. As the result of peripheral growth they give rise to large oval foci with a hyperemic, macerated surface and an elevated edematous edge, which is sometimes covered with vesicles, crusts, and scales. Later the foci may coalesce and form extensive areas of affection the size of a palm with geographic outlines. The centre of the foci pales gradually and becomes slightly depressed. There is a border of desquamating macerated epidermis on the edges. The patients are troubled by mild itching which increases during exacerbations. The disease has a sudden onset as a rule, but then it takes a chronic course and may continue for months and years with periodical exacerbations (particularly in the hot season and in excessive sweating).

The diagnosis is made on the basis of the typical clinical picture, localization of the process, acute onset, chronic course, and the detection of threads of septate mycelium on microscopy of scrapings from the surface of the lesions. The disease is distinguished from erythrasma, candidiasis, psoriasis and rubromycosis.

Treatment. In the acute period, cold lotions with a 3 per cent boric acid solution or 0.25 per cent silver nitrate solution are applied externally, painting the foci with 1-2 per cent iodine tincture for several days, after which 3-5 per cent sulphur-tar or boric acid-tar ointment is prescribed for two or three weeks. It is advisable to apply fungicidal agents: Mycoseptin, Clotrimasol, Lamisil, Nizoral and etc.). In the acute period, hyposensitization therapy should also be conducted.

For the prevention of recurrences after the achievement of a clinical cure, the skin in the region of the cured lesions is painted with 2 per cent iodine tincture daily or every other day.

Tinea Pedis or Epidermophytosis of the Feet, (Epidermophytosis Pedum)

Tinea pedis is a widespread disease encountered in all countries of the world. Its incidence among some population groups (swimmers, workers of public baths and showers, athletes, workers at hot shops, coal mines, etc.) is high and, according to different authors, reaches 60 to 80 per cent. The disease is relatively rare in children.

Etiology. The causative agent is the fungus Trichophyton mentagrophytes, a variant of T. interdigitale.

Epidemiology. The disease is contagious and is transmitted by sick individuals to healthy persons in public baths, swimming pools, showers, and on the beach through infected mats, spreads, flooring, wash basins, and benches. Footwear, socks, and stockings worn by an individual with the disease are contagious, and sharing foot-wear is therefore dangerous. The threads of the mycelium and the spores of the fungus are contained in great amounts in the scales of the epidermal horny layer, which the sick person 'loses' in abundance as a result of which an unfavourable epidemiological situation is created.

Pathogenesis. The conversion of the fungus from a saprophytic to a pathogenic state is promoted by increased sweating of the feet, flat foot, tight interdigital spaces, improperly fitted footwear (this is one of the causes of outbreaks of the disease among recruits), sores, intertrigo, anatomico-physiological properties of the skin typical of each definite age, chemism of the sweat, and alkaline shift in sweat pH. Disturbed function of the nervous and endocrine systems, angiopathies, acrocyanosis and other disorders of the lower limb vascular apparatus, are the endogenic factors, which are favourable for the development of tinea pedis. Mechanical and chemical traumas of the skin on the feet, unfavourable meteorological conditions, and a high environmental temperature are also significant. The degree of the virulence and pathogenicity of the fungal strain should also be taken into account.

Clinical picture and course. The following clinical varieties of tinea pedis are distinguished: subclinical form, squamous-hyperkeratotic, intertriginous, dyshidrotic and unguium. The separation of epidermophytosis of the feet into forms is conventional because a combination of several clinical variants is often encountered or one form may change to another. Epidermophytids are distinguished as a manifestation of an allergic reaction.

The subclinical form of epidermophytosis. The condition is considered either a carrier state or a squamous form without obvious symptoms. Very often the process persists for a long time. Moderate scaling in the interdigital folds, usually between the fourth and the little is found.

The squamous-hyperkeratotic form. Moderate scaling on a slightly hyperemic skin is found on the arches of the feet. The scaling may be restricted to small areas or may extend over large surfaces. Some patients complain of slight itching felt now and again. Quite often the disease remains unnoticed by the person and because of this it is particularly dangerous epidemiologically. In exacerbation of the process, the squamous form may change to the dyshidrotic form and, vice versa, the dyshidrotic form may terminate by the squamous form. At the onset of the disease, the process is always unilateral but later the other foot may also become involved.

The intertriginous form may occur independently but more frequently it develops when there is a squamous form. The process begins in the interdigital folds, usually between the fourth and the little, less frequently between the third and fourth toes. In some cases the disease spreads to the other interdigital folds and then to the flexor surface of the toes and the dorsal surface of the foot. Cracks surrounded on the periphery by a whitish separating horny layer of the epidermis form in the interdigital folds. Weeping surfaces, itching of various intensity, and sometimes (when there are erosions) pain appear.

Very often the process persists for a long time, with remissions in the winter and exacerbations in the warm seasons. The formation of cracks and the looseness of the horny layer in the intertriginous form are conducive to the entry of streptococcal infection.

The dyshidrotic form is characterized by the formation of a group of vesicles on the arch of the foot. The vesicles resemble soft-boiled sago grains, they have a hard top and their size ranges from the size of a pin head to that of a small pea. The vesicles coalesce and form multilocular bullae in whose place eroded surfaces with a ridge of macerated epidermis on the periphery form. The process may extend to the lateral and medial surfaces of the foot and thus forms a single pathological focus with the intertriginous form. The subjective symptoms are itching and pain. With the occurrence of secondary infection the contents of the vesicles turn cloudy, pus is discharged when the vesicles open, and lymphangitis and lymphadenitis may develop. As the inflammatory reaction gradually subsides, the excoriations undergo epithelization, new vesicles do not form, and the focus of affection acquires a squamous character. In severe cases with secondary infection, the patients have to be hospitalized. A characteristic feature is unilateral localization of the process. This form is distinguished by a protracted torpid course, recurrences and exacerbations mainly developing in the spring and summer.

Epidermophytosis of the nails (Tinea unguium). The initial changes form on the free margin of the nail plate as yellow spots and bands. The whole plate then thickens and turns yellow or ochre-yellow, crumbles and breaks easily, and horny material accumulates under it (subungual hyperkeratosis). In some cases the plate becomes thin and is separated from the nail bed (onycholysis). The nail plates of the big and little toes are affected most frequently. The finger nails are never involved in the process. It is claimed that the nail plates are affected in approximately 20 to 30 per cent of patients with epidermophytosis.

Diagnosis. With a characteristic clinical picture and threads of the fungal mycelium found by microscopy the diagnosis is easily made. The disease is distinguished from hyperdiagnosis, eczema of the feet, candidiasis of the interdigital folds, intertrigo, etc.).

Epidermophytids are secondary allergic eruptions occurring because the fungus Trichophyton mentagrophytes, a variant of T. interdigitale, possesses potent toxico-allergenic properties and sensitizes the patient's organism imperceptibly for a long time. They are mostly localized on the palms and fingers. The morphological character of the epidermophytids may be diverse: erythemato-squamous, urticario-exudative, dyshidrotic (vesicular), pustular or eczematous. Generalized epidermophytids are often attended with general symptoms: temperature reaction, chill, indisposition, and sometimes severe itching. Eczematous and dyshidrotic epidermophytids may take a protracted course and in inadequate treatment, transform to eczema.

Treatment. The treatment varies depending on the clinical form of tinea pedis, but the condition common for all forms is as follows: the more acute the process, the lower must be the concentration of the fungicidal and disinfectant agents. Treatment of acute epidermophytosis is conducted on the same principles as treatment of acute eczema: hyposensitization therapy (calcium preparations, antihistaminics) and topical anti-inflammatory treatment (cooling lotions or warm foot baths with potassium permanganate); the lesions are previously treated (the bullae and vesicles are opened, the tops are removed, the separating epidermis is cut off, etc.).

With gradual abatement of the inflammation (in the dyshidrotic and intertriginous forms of epidermophytosis) treatment with desquamative and fungicidal agents is applied, increasing gradually their concentration: 3-5 per cent sulphur-tar or salicylic-tar pastes, or afungil ointments. Arievich's ointment which cause separation of the horny layer is prescribed in squamous epidermophytosis (Ac. lactici 6.0, Ac. salicylici 12.0, Vaselini ad 100.0). After the horny material is rejected, Castellani's paint and fungicidal ointments (Micozolon, Mycoseptin, Clotrimasol, Lamisil, Nizoral) are applied.

The treatment of tinea unguium is discussed in the section dealing with the treatment of onychomycoses in rubromycosis.

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