Granuloma annulare is a chronic benign skin lesion that has an unexplained etiopathogenesis. The disease is manifested by ring-shaped rashes on the skin, which consist of dense purple or brick-red nodules, can occur in a localized, generalized or atypical form. To diagnose the condition, a thorough clinical examination, histological examination of biopsies of the affected areas, and an extended laboratory examination are required. Treatment includes topical corticosteroids, retinoids, immunosuppressors, hardware methods of fractional photothermolysis, cryodestruction.
L92.0 Granuloma annulare
The disease was first described by the English scientist T. Fox. There are no large-scale studies of this disease in dermatology, so the frequency of occurrence has not been precisely established, and treatment regimens have not yet been finalized. Women get sick 2-2.5 times more often. There are two age peaks of morbidity: the localized form of granuloma annulare is typical for young patients under 30 years old, and in most cases it has a favorable course, and the common form occurs in people over 50 years old, combined with other somatic pathologies, difficult to treat.
In modern dermatology, the exact etiological factors of the development of the disease have not yet been determined. Previously, it was believed that the pathology is idiopathic in nature, but new studies prove the involvement of various endogenous health disorders and exogenous factors in the mechanism of its development. To date, the following groups of triggers specific to granuloma annulare have been described:
- Burdened heredity. Chronic dermatosis is associated with the genes of the main histocompatibility complex (HLA), and the presence of the HLA-B8 antigen is typical for localized forms, and the presence of the HLA—A29 antigen is typical for disseminated forms.
- Diabetes mellitus. People with impaired glucose metabolism are much more likely to experience symptoms of granuloma annulare, they are characterized by a common form of dermatosis with localization of elements in different parts of the body. Pathology is most often observed in type 1 diabetes mellitus, it can occur already in childhood.
- Chronic diseases. The provoking factor of skin lesions can be sarcoidosis, rheumatism, autoimmune thyroiditis. The risk of dermatosis increases sharply in patients with chronic hepatitis B, tuberculosis.
- Malignant tumors. According to a number of authors, the appearance of skin rashes is possible against the background of solid tumors of the breast, cervix, prostate, gastrointestinal tract. Occasionally, the cause of granuloma becomes oncopathology of the blood (Hodgkin’s lymphoma, acute myeloblastic leukemia).
- Exogenous factors. Some authors associate the disease with excessive and prolonged exposure to ultraviolet radiation. Sometimes dermatosis develops after insect bites.
- Taking medications. The trigger of the disease is the tuberculin Mantoux test, vaccination against tuberculosis. Treatment with gold preparations, some anti-inflammatory and antihypertensive medications can also provoke pathology.
The mechanism of development of granuloma annulare is explained by a typical delayed hypersensitivity reaction that occurs idiopathically in response to the action of unknown antigens. Antigen-presenting macrophages and dendritic cells play an important role in pathogenesis. All cellular elements provide antigen phagocytosis and its presentation to T-lymphocytes, which culminates in the proliferation of antigen-sensitive Th1 clones.
During pathomorphological examination, Th1 lymphocytes, an increased level of proinflammatory agents: gamma interferon, tumor necrosis factor, interleukins of the second and fourth types are determined in the focus of the skin lesion. This process ends with limited degeneration of collagen fibers of the dermis, which distinguishes pathology from diffuse lipid necrobiosis.
Taking into account the histological picture, there are two variants of granuloma annulare: interstitial and front garden. In the interstitial type of the disease, clusters of mucin and histiocytes form between the fibers of the dermis. For the front garden variant of dermatosis, granulomatous infiltrates in the papillary layer of the dermis are typical, in the center of which clusters of leukocyte cells in the form of a palisade are determined.
This type of pathology is usually found in the practice of a dermatologist. Skin damage is represented by one or more rounded foci with a diameter of 1-5 cm, the edges of which rise above the surface of the skin. They consist of closely spaced nodules of pink or bluish hue. The central part of the foci is represented by slightly pigmented skin. Foci are prone to peripheral growth.
The localized form of dermatosis is characterized by the absence of peeling and other secondary elements of the rash. Rashes are located on the back of the hands, extensor surfaces of the elbow and knee joints, in front of the shins. Typically, the lesion of places that are subjected to chronic traumatization has a minimal layer of subcutaneous tissue. Granuloma annulare is not accompanied by itching, pain or other uncomfortable sensations. It lends itself well to traditional treatment regimens.
The disseminated variant of the disease is diagnosed in 8.9% of patients. The average age of patients with skin lesions is 52 years. The condition is manifested by multiple isolated or merging rashes, which are mainly located on the neck, trunk, palms and soles. The rash has the appearance of nodules of bluish, yellow-brown or flesh color, which are accompanied by skin itching.
This type of pathology is characteristic of childhood, although several cases of dermatosis in adults have been described. Dense painless nodes no more than 4 cm in diameter appear on the skin. They are mainly located on the scalp, in the periorbital zone, on the lower extremities — in the buttocks, anterior inner surface of the shins, the back of the foot. These elements are similar to rheumatoid nodules.
A rare and most dangerous variant of pathology, which is mainly detected in residents of the Hawaiian Islands. The foci of dermatosis are localized on the back of the hands, trunk, and lower extremities. Rashes are represented by miliary or lenticular papules with an umbilical depression in the central part, which can be opened with the release of gelatinous fluid. After the healing of the elements, atrophic scars remain.
This type of granuloma annulare is most typical for women over 40 years old. Skin elements cover the trunk, limbs, occasionally dermatosis becomes generalized. Patients notice spots of red, brick or bluish color with a uniform color, which do not hurt and do not itch, deliver only aesthetic discomfort.
Although granuloma annulare is a benign disease, it can cause negative consequences. The generalized variant of dermatosis is the most difficult to treat, even with the use of modern hardware techniques. In addition, many patients face recurrent rashes for several months or years after undergoing a therapeutic course.
Since in sufferers of granuloma annulare, the lesion spreads to deep areas of the dermis, the healing of large foci of dermatosis can occur through the stage of scar formation. Unaesthetic bright pink scars appear on the skin of patients, which brighten noticeably after 3-4 months, and then acquire a dense structure and final appearance for six months.
Unaesthetic skin manifestations of granuloma annulare do not affect the general state of health, do not cause systemic complications. The need for timely access to a doctor is largely dictated by the importance of differential diagnosis and the exclusion of more dangerous types of dermatoses, which may be similar to granuloma in clinical signs.
In typical cases, the diagnosis of granuloma annulare is performed by a dermatologist based on the data of a clinical examination and the collection of a detailed anamnesis. Since dermatosis is characterized by polymorphism of symptoms, timely detection of pathology is often difficult. To confirm the diagnosis and start treatment, the following research methods are used:
- Histological analysis. When examining skin biopsies of damaged areas, cellular infiltrates in the middle and lower layers of the dermis, foci of coagulation necrosis, degeneration of collagen fibers are determined. The cellular composition is represented by lymphocytes, histiocytes, fibroblasts.
- Blood tests. In localized variants of granuloma annulare, there are no changes in clinical and biochemical studies. In the disseminated variant, manifestations of dyslipidemia, hypertriglyceridemia, increased ESR and acute phase proteins are possible.
- Immunogram. Since allergic reactions play an important role in the pathogenesis of the disease, in order to get a complete picture, the doctor needs indicators of different fractions of T-lymphocytes, levels of immunoglobulins, proinflammatory cytokines.
- Microbiological diagnostics. Studies are conducted to exclude infectious dermatoses, the clinical symptoms of which are similar to the manifestations of granuloma annulare, as well as to check for chronic infections as a typical trigger of the disease.
- Consultations of specialists. If a chronic somatic pathology is suspected, which provoked the development of granuloma annulare, the patient must undergo an extended examination by an endocrinologist, rheumatologist, oncologist.
With atypical clinical variants, it is necessary to make a differential diagnosis with infectious skin lesions (tuberculous leprosy, tuberculous syphilis), other chronic dermatoses (persistent towering erythema, ring-shaped form of lipid necrobiosis). It is also required to exclude small-nodular sarcoidosis, rheumatic nodules.
Granuloma annulare treatment
Clear clinical protocols for the treatment of granuloma annulare have not been developed. In children, dermatosis mostly regresses on its own, adults, as a rule, require specific therapy. Treatment is selected by the doctor individually, taking into account the clinical form of the disease, the size and localization of the rash, the degree of aesthetic discomfort. The following groups of drugs are used:
- Corticosteroids. Topical hormonal preparations in the form of ointments and creams are used to treat the local inflammatory process. Since pathological changes occur deep in the dermis, it is recommended to inject strong steroids that are guaranteed to have a therapeutic effect. Treatment may include injecting hormones into the annular foci.
- Retinoids. To improve the histological structure and appearance of the affected skin, the possibility of selecting local remedies with retinol and its derivatives is being considered. In rare cases, treatment is supplemented with systemic retinoids.
- Immunosuppressors. They are effective in disseminated granuloma annulare in order to influence the pathogenetic mechanisms of its formation and accelerate the regression of foci covering the skin. Limited effectiveness in treatment is shown by medications from the sulfone group.
- Hypolipidemic agents. With generalized granuloma, patients often experience the phenomena of hyperlipidemia and dyslipidemia, which require drug correction. To increase the effectiveness of treatment with these drugs is supplemented with diet therapy.
- Monoclonal antibodies. Treatment of severe recurrent forms of the disease can be carried out with the use of drugs that inhibit the tumor necrosis factor. These agents inhibit the pathophysiological mechanisms of dermal lesion, reduce the inflammatory component of dermatosis.
Fractional photothermolysis is considered a promising direction of pathology treatment. The treatment is based on the treatment of skin elements with erbium laser micro-rays, which cause limited cell destruction (microthermal treatment zones). Local exposure triggers the regeneration processes of healthy skin, contributes to the reduction or complete disappearance of rashes.
To eliminate large foci of granuloma annulare, minimally invasive treatment may be indicated on exposed parts of the body. To eliminate the cosmetic defect, treatment with laser destruction and cryotherapy is prescribed. Such methods are carried out only after a course of conservative treatment and after a certain time after the diagnosis of the disease, since spontaneous resolution of rashes is not excluded.
Prognosis and prevention
Complex treatment of localized granuloma annulare contributes to the regression of dermal inflammatory foci, therefore, the prognosis for patients with this form of pathology is favorable. With generalized dermatosis and rare forms of granulomatous lesions, the prognosis is doubtful, since treatment is not always effective, and the probability of recurrence is about 40%.
In the prevention of the disease, timely detection and treatment of endocrine pathology, systemic connective tissue diseases, and malignant tumors are put in the first place. It is recommended to avoid prolonged exposure to the sun during the midday hours, and during periods of increased activity of ultraviolet rays, it is worth using high-quality sunscreens.