Cutaneous leishmaniasis: causes, symptoms, diagnosis, treatment

Leishmaniasis cutaneous (synonyms: Leishmaniasis of the Old World, Borovsky's disease) is an endemic transmission disease, found mainly in countries with hot and warm climates, manifested primarily by skin lesions.

Causes and pathogenesis of cutaneous leishmaniasis. The causative agent is the simplest Leishmania tropica. The carriers of the disease are different kinds of mosquitoes. There are basically two varieties of leishmaniasis: anthroponous (urban type) caused by Leishmania tropica minor and zoonotic (rural type), caused by Leishmania tropica major.

The source or reservoir of a rural type of infection of cutaneous leishmaniasis is rodents and gerbils, and urban - a sick person.

For cutaneous zoonotic leishmaniasis, seasonality is characteristic, i.e., the disease occurs in summer and autumn, the anthroponous type occurs year round.

It occurs mainly in Central Asia, Azerbaijan. The main reservoirs of infection are rodents (gophers, gerbils), carriers - mosquitoes. There are two types of disease: rural, or acute necrotic, caused by Leishmania tropica major, and urban, or late ulcerated, caused by Leishmania tropica minor. In rare cases, a tuberculoid (lupoid) variant is observed, which usually occurs in the zone of regressed lesions in the urban type of leishmaniasis due to the reactivation of surviving leishmanias due to general or local immune disorders.

Rustic type proceeds acutely, furuncle-like elements develop on the site of bites, after ulceration of which crater-like ulcers arise scarring during 3-8 months. Lymphangites are characteristic.

At the urban type, the development of elements of a smaller size is observed than with an acute necrotizing leishma-nioze, they last for a long time (5-6 months) exist without ulceration, slowly heal (on average for 1 year). The duration of the inflammatory process is associated with the predominance of lymphocytes with suppressor properties in the infiltrates.

Symptoms of cutaneous leishmaniasis. Cutaneous leishmaniasis proceeds cyclically: note the primary (stage of tuberculation, ulceration, scarring), sequential (early, late), diffuse-infiltrating leishmaniomas and tuberculoid.

Leishmaniasis cutaneous zoonotic. The incubation period ranges from one week to two months. At the site of the mosquito bite, a painful, flattened, acute-inflammatory tubercle of bright red color is formed, 3-5 mm in size. The tubercle becomes a furuncle-like infiltrate with fuzzy boundaries. The infiltrate increases in size, reaching 10-15 cm in diameter, and after 2 weeks the central part of it quickly undergo necrosis, necrotic masses are rejected and a small-sized crater ulcer (5-8 mm in diameter) is formed, with a purulent discharge around which there is a wide zone of infiltration with inflammatory edema of the surrounding tissue.

In the future, the bottom of the ulcer is cleared of necrotic masses and red papillary granular growths appear resembling caviar. Ulcers round, oval or irregular in shape, their edges are even, dug, then scalloped, as if eaten. Around the main there are new ulcers. Specific complications of cutaneous leishmaniasis include lymphangitis around ulcers and lymphadenitis. From the upper edge of the ulcer appear dense, painless nodes ranging in size from a small pea to a hazelnut. Later on, in these nodes inflammation can intensify and lead to ulcer decay. On the limbs, there are distinct lymphangites. The process is accompanied by soreness, development of swelling of the feet and legs. After 3-6 months the process ends with scarring.

Leishmaniasis cutaneous anthroponous. The incubation period is from 3 to 6 months (rarely - up to 3 years). At the site of the pathogen introduction, a leishmanioma appears in the form of a smooth, slowly growing brownish-red tubercle 1-2 mm in size. Gradually the tubercle grows, speaking above the level of the skin, and after 6 months reaches 1-2 cm in diameter.

In the central part of the element there is a crater-like depression, which has horny scales, which are sometimes impregnated with exudate and turn into scaly crusts. Six to eight months after the rejection of the blood-purulent crust, a ulcerative defect is formed. The ulcer is rounded, surrounded by an ascending infiltrate, with an uneven reddish bottom, pitted edges, serous-purulent lean separates into the brown crust. Around the ulcer, new tubercles and ulcers of contamination can appear. On the limbs, there are clear lymphangites. After about a year (sometimes more), the infiltrate decreases, the ulcer clears, the islets of the granulation tissue appear and it begins to scar.

Sometimes the healing of the granulation tissue takes place under the crust in a dry way. The general condition of patients is not violated.

Leishmaniasis tuberculoid is one of the variants of leishmaniasis, which develops in individuals with altered reactivity of the organism as a result of activation of surviving leishmanias or as a result of natural superinfection. This type of leishmaniasis is common in children or young people. The disease develops either in the process of reverse development of the primary leishmanioma of the anthropophilic type or in the postleismanial scars area. Around the healing focus of the lesions appear tubercles of 2-5 mm, yellow-white with a sign of stagnant red. Elements are hemispherical flat, with a smooth, sometimes peeling surface. The tubercles often surround a fresh scar, can develop on an already formed scar and persist for a long time. The appearance of new elements contributes to the increase of the lesion zone, exciting new areas of the skin. Then, during the reverse development, they leave atrophy or may ulcerate, covering with a yellow-brown crust. In appearance, the tubercles resemble lupomas in tuberculous lupus, so the disease is often called lupoid leishmaniasis.

In our country, American skin leishmaniasis, which is caused by Leishmania brasiliens, is described in a patient who has come from an endemic zone. This form of leishmaniasis differs from Borovskii's disease by frequent damage to the mucous membranes of the upper respiratory tract, the oral cavity, the presence of early (at the site of bites) manifestations of ulcerative tubercles and nodes, and late, arising after several years, in the form of granulomatous-destructive and ulcerative lesions .

Pathomorphology. In the acute period, an infiltrate is found in the dermis, consisting mainly of macrophages filled with a large number of pathogens, among them are lymphoid and plasma cells. When ulceration in the infiltrate also reveal neutrophilic granulocytes, leishmanias can be not only inside macrophages, but also outside them. A few months later, foci of the tuberculoid structure appear, the number of macrophages and leishmanias decreases. In the chronic course of the process, a tuberculoid infiltrate is detected, which is difficult to distinguish from tuberculosis. However, the absence of caseous necrosis and the presence of plasma cells, as well as leishmanias, help diagnose leishmaniasis. With the tuberculoid form of leishmaniasis (metalishmaniasis), the signs of both acute and chronic process are revealed in the histological picture. In the dermis - an infiltrate from macrophages with an admixture of lymphocytes and plasma cells and tuberculoid structures. Leishmania is rare.

Histopathology. Detect a granulomatous infiltrate, consisting of epithelioid cells, lymphocytes, histiocytes. Among the epithelioid cells, giant cells such as Pirogov-Langhans are seen.

The diagnosis is based on the detection of leishmanias in the lesions.

Differential diagnosis is carried out with tuberculosis, syphilis, pyoderma, sarcoidosis.

Treatment of cutaneous leishmaniasis. Prescribe antibiotics - monomycin, doxycycline, metaiklin, antimalarial drugs - delagil, plakvenil (including for obkalyvaniya unopened leishmaniom). They produce cryodestruction, laser therapy. There are reports of the effectiveness of lamizil (250 mg per day for 28 days).

Individual prevention consists in using mosquito repellent (curtains, nets, repellents). Public prevention consists in the elimination of mosquito breeding sites, mosquito treatment (focal disinsection), extermination of gerbils (with zoonotic type).

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