Scrofuloderma is a common childhood and adolescent form of tuberculous skin lesions. It is a dense fluctuating node without a typical localization, more often single, less often multiple, with a tendency to slow growth. It is resolved by fistulas with ulceration and bloody-purulent discharge. The outcome is scarring with a specific “bridge–like” scar. Scrofuloderma can be primary (hematogenic) and secondary (lymphogenic). The disease is diagnosed clinically using tuberculin samples, radiography, histology and microscopy. Treatment is carried out with anti-tuberculosis drugs.
ICD 10
A18.4 Tuberculosis of the skin and subcutaneous tissue
General information
Scrofuloderma is a local form of tuberculous lesion of the skin by the type of “cold” (sluggish) inflammation. It occurs only in children and adolescents. It is characterized by single, rarely multiple deep–lying nodes in the dermis, which occur primarily in previously uninfected patients or secondarily in patients suffering from tuberculosis of internal organs for many years. Scrofuloderma has no seasonality and gender component, does not have endemicity, but is very contagious.
The share of scrofuloderma accounts for more than a quarter of all tuberculous pathology of the dermis. However, doctors of different specialties, especially district pediatricians, meeting with early manifestations of pathology, do not have professional alertness in the diagnosis of clinical manifestations, most often taking scrofuloderma for banal pyoderma. This contributes to the late diagnosis of colliquative tuberculosis, ulceration of primary elements with the formation of skin-disfiguring scars, which remain a kind of “black mark” in the patient for the rest of his life.
Causes
The cause of the disease is acid–resistant mycobacterium Koch, discovered in 1882. It is an aerobic wand that does not have a capsule and does not form spores. Under a microscope, it is determined only when stained according to Zil-Nielsen. There are two ways of infection with scrofuloderma:
- Hematogenic. Initially, the infection enters the body by airborne droplets and affects the internal organs, from which mycobacteria with blood flow are introduced into the skin.
- Lymphogenic. Infection of the skin occurs a second time against the background of long-term tuberculosis of internal organs with lymph node damage and lymphogenic migration of mycobacteria from pathogenic lymph nodes into the skin.
Pathogenesis
The mechanism of development of scrofuloderma is the formation of tuberculous granuloma. The speed of formation of the primary element depends on the number of mycobacteria that have penetrated the skin, their virulence and the state of the patient’s immune system. Tuberculous inflammation in scrofuloderma is a classic example of an autoimmune process.
T-lymphocytes of the immune system sensitized to mycobacteria, upon penetration into the skin, begin to actively bind antigens foreign to the body, which are Koch sticks. Thus, they prevent the development of scrofuloderma. However, there comes a time when there are too many microbes, they “occupy” the skin, get embedded in it, and T-lymphocytes begin to bind their own skin cells together with mycobacteria. There is an autoimmune process that causes additional sensitization of the skin. The destruction of the skin layers occurs with the development of granuloma.
In turn, mycobacteria at the site of their introduction into the dermis tissue trigger the mechanism of “cold” sluggish inflammation, which is based on the impossibility of complete “digestion” of Koch’s bacillus by phagocytes of the body’s immune system. Local immunity is forced to work with a vengeance, destroying mycobacteria and infected skin cells entering the focus. As a result, phagocytosis becomes incomplete. “Undigested” mycobacteria form an inflammatory infiltrate at the base of the granuloma, consisting of immune cells and dead Koch sticks. This is how the primary element of the scrofuloderm is formed – the fluctuating node. Scrofuloderma is often combined with other forms of tuberculosis of the skin.
Classification
In clinical dermatology, it is customary to distinguish two variants of scrofuloderma that have different ways of occurrence:
- Primary hematogenic scrofuloderma. Occurs in patients who have not previously had tuberculosis, when mycobacteria enter the skin with blood flow.
- Secondary lymphogenic scrofuloderma. It develops in patients suffering from tuberculosis for a long time. Granuloma is formed as a result of secondary contamination of the skin with mycobacteria from infected lymph nodes.
Symptoms
Clinical manifestations of scrofuloderma have slight differences depending on the form. The hematogenic form is localized on the extremities (around the joints), face and neck, characterized by the appearance of oval, dense, slightly painful, deep-lying nodes in the layers of the skin up to 5 cm in diameter. The primary elements are soldered to the underlying tissues, have a bluish color, are prone to opening and formation of deep ulcers with bloody-purulent discharge and the formation of necrosis sites. Healing is sluggish, “torn” scars with “bridge-like” bridges disfiguring the skin are formed.
Foci of lymphogenic scrofuloderma occur in the cervical and submandibular lymph nodes. They are characterized by the appearance in the dermis and subcutaneous adipose tissue of dense primary tubercular elements of a reddish-purple color, which tend to slow growth, fusion with each other and the formation of conglomerates, which, abscessed, open on the surface in the form of fistulas and ulcers. Usually such formations are shallow, with smooth dough-like edges and a curd secret at the bottom. They are scarred slowly, initially entangling the entire surface of the skin defect with a web of bridge-like bridges, and then filling the remaining gaps with granulations. After healing, a disfiguring scar is formed.
Diagnostics
The diagnosis of scrofuloderma is made on the basis of anamnesis, clinical picture and the results of X-ray examination, which is carried out in order to establish the primary focus of tuberculosis lesion. When making a diagnosis, the typical localization of the process is taken into account. If there are difficulties in the process of differential diagnosis of scrofuloderma, a histological examination is performed. Morphological changes in both forms of scrofuloderma are identical and are reduced to the formation of a nonspecific infiltrate with foci of necrobiosis infiltrated by mononuclear cells. Mycobacteria are located in the upper layers of the affected area of the skin, which facilitates the diagnosis of scrofuloderm.
The results of tuberculin tests may vary in different age categories. Older children give a sharply positive Mantoux reaction, patients of younger age groups respond non-specifically. Scrofuloderma is differentiated from other local forms of tuberculosis of the skin, syphilitic gum, pyoderma, actinomycosis, Bazin’s erythema, vulgar ecthyma and hydradenitis. In doubtful cases, an in vitro blood test is performed: T-SPOT.TB or quantiferon test. Along with a dermatologist, the patient is advised by a phthisiologist.
Treatment
Therapy is carried out in closed hospitals, taking into account the contagiousness of patients. Prescribe specific anti-tuberculosis drugs according to individual schemes with the calculation of the course dose per kilogram of the patient’s weight (PASC, calcium benzoylaminosalicylate). Topically applied UVI, dressings with miramistin, etacridine lactate, potassium permanganate solution and iodoform.
With a mild course of the disease, the prognosis is favorable. With ulceration, scrofuloderma becomes chronic, does not respond well to therapy, recurs, lasts for years.
