Papulonecrotic tuberculosis is an infectious disease of the skin of tuberculous etiology, the distinctive features of which are the paroxysmal nature of the rash of primary elements and the prevalence of the pathological process. Clinically, papulonecrotic tuberculosis is characterized by the appearance of dense multiple nodules – hemispheres with a diameter of 1 to 4 mm of all shades of purple with central necrosis. The pathological process is diagnosed on the basis of typical manifestations and confirmed by the results of histology. Treatment is carried out with anti-tuberculosis drugs, vitamins, UFOs.
A18.4 Tuberculosis of the skin and subcutaneous tissue
Papulonecrotic tuberculosis is a type of chronic recurrent infection of the skin caused by Mycobacterium tuberculosis and characterized by dissemination of the pathological process. Papulonecrotic tuberculosis was first described by the Austrian pediatrician F. A hamburger. The disease occurs more often in children and young women, has no racial differences, is not endemic. It can develop at any time of the year, but relapses are usually observed in spring and autumn.
Despite the fact that the disease belongs to the group of dermatoses with an established cause of occurrence, there are many ambiguities in the epidemiology of papulonecrotic tuberculosis. According to official statistics, the share of the pathological process accounts for only 1% in the structure of the incidence of tuberculosis, which is comparable to the statistical error. Since we are talking about a visually diagnosed form of tuberculosis infection, there are doubts about the reliability of such data. In all likelihood, the problem lies in the low registration of papulonecrotic tuberculosis due to insufficient tuberculosis alertness of practitioners, underestimation of the significance of the disease and erroneous diagnosis of nonspecific forms of skin lesions instead of a specific tuberculosis infection. An indirect proof of the high probability of diagnostic errors is an insignificant percentage of pathology in the structure of morbidity.
Incorrect diagnosis of the pathological process, underestimation of its prevalence, the increase in the number of patients with papulonecrotic tuberculosis in Europe and Russia, combined with the need for thorough differential diagnosis of the disease with other dermatoses, makes the problem particularly relevant at the present stage.
The causative agent of the disease is Mycobacterium tuberculosis of the human type, or Koch’s bacillus – an aerobic microorganism that develops only in the presence of oxygen. However, the skin, perfectly supplied with oxygen, due to the peculiarity of the acidic environment of the dermis, is an unfavorable environment for the reproduction of mycobacteria. Therefore, infection as a result of the primary ingestion of mycobacteria directly on the surface of the dermis with papulonecrotic tuberculosis is rare.
Despite the fact that there are special antigens in the structure of mycobacteria that stimulate sensitization of the skin, a combination of a large number and high virulence of microbes is necessary. Only in this case, it is possible to reduce the local T-cell immunity of the skin with the development of an allergic reaction and the formation of primary elements, which occurs extremely rarely. In addition, the state of general immunity plays an important role.
The basis of the pathological process is an inflammatory reaction of the inner shell of the capillaries caused by an allergic reaction of an antigen-antibody. The role of the antigen is performed by mycobacterium, which has hematogenically entered the skin from a focus of tuberculosis infection that already exists in the body, including in the latent version. Regional lymph nodes, intestines, affected joints and internal organs can act as foci of infection.
In response to the introduction of the antigen into the skin, the immune and reticular systems of the dermis begin to produce antibodies, sensitizing the layers of the skin and the structures located in it, including capillaries. The cells involved in the allergic process begin to produce biologically active substances that change vascular permeability. Inflammation occurs in the inner shell of small vessels, which facilitates the entry of the pathogen of the pathological process from the bloodstream into the skin and causes the development of vasculitis, which is the basis of papulonecrotic tuberculosis.
Depending on the degree of skin lesions in modern dermatology, two variants of papulonecrotic tuberculosis are distinguished: superficial (folliculitis) – a type that affects the surface layers of the dermis and does not leave scars when the elements resolve, and deep (acnitis) – a type that affects the deep layers of the dermis and regresses with the formation of typical “stamped” scars. Each variant, in turn, is divided into two varieties.
- Papular variety – the primary element is a papule of inflammatory genesis, small, dense to the touch.
- Pustular variety – the primary element is a pustule that occurs in place of the papule, filled with translucent contents that are released when pressed.
- Pustular form – the primary element is a millimeter pustule with necrotic masses inside and a crust in the center, when the crust is removed, an ulcer opens with an outcome in the scar in the form of a “stamp”.
- Papular-pustular – the primary element is a crater-shaped five-millimeter papular pustule filled with pus and covered with a crust with necrosis in the center. The element is resolved by scarring with the formation of a brown border around the perimeter of the scar against the background of decreased immunity and negative tuberculin tests.
Clinically, the disease is manifested by a paroxysmal rash of primary elements in the form of dense small brown-purple papules in the form of hemispheres located close to each other. Papules are painless, asymmetrically localized on the extensor surfaces of the limbs, on the trunk, less often on the face. Purulent necrosis appears in the center of the papules, crusts form, which, falling away, expose an ulcerative bleeding surface, resolved by scarring in the form of specific “stamped” scars with a purple border around the perimeter – the hallmark of papulonecrotic tuberculosis.
When resolving surface forms, scars are not formed. The whole cycle takes from one to two months. Externally, the primary elements resemble youthful acne. The general well-being of patients with the development of the disease is usually not disturbed, in weakened patients, prodroma phenomena are possible.
The diagnosis is made by a dermatologist based on clinical symptoms, typical “stamped” scarring, histology data, positive tuberculin samples and radiography of the primary tuberculous focus. Tuberculin samples include a Mantoux test, a Koch test and a skin graded tuberculin test. In difficult cases, they resort to an ELISA blood test (T-SPOT.TB test, interferon test). Histologically, the lesion of all layers of the skin and subcutaneous fat is determined in the form of an epithelioid cell granuloma with giant Langhans cells surrounded by a shaft of T-lymphocytes.
Differential diagnosis is carried out with juvenile acne, annular granuloma, oil folliculitis, nodular vasculitis, malignant pustulosis, tubercular syphilis, teardrop-shaped parapsoriasis, nodular prurigo (pruritus), lymphomatoid papulosis.
The therapy is complex, carried out by a phthisiologist after consultation with a dermatologist and an infectious disease specialist, includes the use of anti-tuberculosis drugs according to individual schemes (per kilogram of the patient’s weight) in combination with vitamin therapy, iron preparations and immunostimulants. The use of UVI is effective. If the process is localized on the face, you may need to consult a cosmetologist.
The prognosis in the absence of serious primary tuberculosis pathology is favorable. Prevention consists in good nutrition, hardening, early detection and timely treatment of pathology. Mandatory dispensary observation.