Lipoid necrobiosis: causes, symptoms, diagnosis, treatment

Necrobiosis lipoidica (synonyms: lipoid diabetic necrobiosis, atrophic macular lipoid dermatitis) occurs in 4% of patients with diabetes mellitus.

The causes and pathogenesis of lipoid necrobiosis have not yet been fully established. It is believed that the basis of the disease is microcirculatory disorders, in the occurrence of which toxins circulating in the blood, immune complexes, neuroendocrine disorders are of great importance. Lipoid necrobiosis is often found in patients with diabetes mellitus, since diabetic microangiopathy is accompanied by disorganization of connective tissue and deposition of glycoprotein on the walls of blood vessels. As a result, lipids are deposited in the lesion. Trigger factors can be various skin injuries (bruises, scratches, insect bites, etc.). There are reports on the role of lipid peroxidation in the pathogenesis of lipoid necrobiosis.

Symptoms of lipoid necrobiosis. Clinically, there are usually scleroderma-like plaques, most often located on the anterior surface of the shins with sharply expressed central cicatricial atrophy and telangiectasias, sometimes with ulceration; less often, superficial scattered foci with little or no compaction and barely noticeable atrophy, surrounded by stagnant erythema: scattered or grouped nodular rashes with the formation of foci similar to annular granuloma. Rare variants are: papulonecrotic, sarcoid-like, resembling persistent elevated erythema, panniculitis, erythema nodosum, xanthomas, lupus erythematosus, malignant atrophic papulosis of Degos.

Lipoid necrobiosis can occur at any age. Women are more often affected. In most patients, lesions are localized on the lower extremities (shins, feet), but can also occur on other areas of the skin. The disease begins with the appearance of spotted or nodular elements, the color of which varies from yellowish-reddish, reddish-brown to lilac. The elements have clear boundaries, a smooth surface, a rounded or irregular shape, and slight infiltration. Sometimes there is slight peeling on the surface. Over time, peripheral growth and fusion of these elements is noted, resulting in the formation of round or oval plaques, polycyclic outlines, consisting of a peripheral and central part. The peripheral part has a reddish-brown or red-bluish tint and is slightly elevated above the level of the surrounding skin. The central part is yellowish-brown or ivory in color with a smooth surface and is slightly sunken. The lesion sometimes resembles plaque scleroderma. Quite often, numerous telangiectasias are observed on the surface of the lesions, and as a result of trauma - erosions, ulcers. Subjective sensations are absent.

In addition to the classical form described above, there are scleroderma-like, superficial plaque, annular granuloma-type forms of lipoid necrobiosis.

The scleroderma-like form is the most common. It is characterized by the presence of single, less often multiple rounded plaques of irregular outlines with a shiny surface on the skin. Due to pronounced infiltration, scleroderma-like compaction is determined during palpation of the lesions. The skin above the lesions does not gather into folds. The process often ends with the formation of rubnevitic atrophy. In some patients (especially with diabetes mellitus), superficial ulcers of irregular outlines with soft, slightly undermined edges appear on the surface of the lesions. The ulcers have a serous-hemorrhagic discharge, which dries up to form dark brown crusts. Subjective sensations are usually absent, only with ulceration does pain appear.

Lipoid necrobiosis of the annular granuloma type is often localized on the hands, wrists, and less often on the face and trunk. The lesions are ring-shaped, surrounded on the periphery by a ridge of bluish-red or pinkish-bluish color with a yellowish tint. In the center of the lesion, the skin appears slightly atrophic or unchanged. The clinical picture resembles annular granuloma.

The superficial plaque form is characterized by the formation of multiple plaques of round or irregular scalloped outlines, ranging in size from a small coin to the palm of an adult or larger, pinkish-yellowish in color, bordered by a purple-reddish or lilac-pink rim 2-10 cm wide. There is no compaction at the base of the plaques, and fine-lamellar peeling is possible on their surface.

Histopathology. Hyperkeratosis and, occasionally, atrophy and vacuolar degeneration of the basal layer are observed in the epidermis. The dermis shows productive vascular changes, collagen necrobiosis, lipoid deposition, and an infiltrate consisting of histiocytes, lymphocytes, fibroblasts, epithelioid, and giant cells of foreign bodies. The walls of blood vessels show characteristic signs of diabetic microangiopathy (fibrosis and hyalinosis of the walls, endothelial proliferation, and thrombosis of small vessels). Depending on the histological picture, a granulomatous or necrobiotic type of tissue reaction is distinguished. Lipoid deposits are revealed when stained.

Pathomorphology. Two types of changes are possible in the dermis: necrobiotic and granulomatous. In the necrobiotic type, predominantly in the deep parts of the dermis there are various sized, vaguely limited foci of necrobiosis of collagen fibers. The fibers are amorphous, basophilic, a small amount of "nuclear dust" is determined.

Perivascular and focal infiltrates of lymphoid cells, histiocytes, fibroblasts, sometimes with groups of epithelioid cells, are located along the periphery of necrobiosis foci, as well as throughout the dermis and even in the subcutaneous fat layer. Giant multinucleated cells of the foreign body type are often encountered. Significant changes in the vessels are noted: endothelial proliferation, wall thickening, and narrowing of the lumens. When stained with Sudan red and scarlet, large amounts of fat are often (but not always) found in necrobiosis foci, stained a rusty-brown color, in contrast to the orange-red color of the neutral fat of the subcutaneous fat layer. Granulomatous foci consisting of histiocytes, epihelioid and giant cells are visible in the granulomatous type of changes. The foci of necrobiosis and fat deposits are less clearly expressed than in the necrobiotic type, and are sometimes absent. Some authors consider changes of this nature to be manifestations of a specific disease - progressive chronic discoid granulomatosis of Miescher-Leder (granulomatosis discifoimis chronica progressiva Miescher-Leder). The epidermis in lipoid necrobiosis is unchanged or somewhat atrophic, and is destroyed in the ulceration foci. In old foci, sclerosis is expressed, small vessels in these areas are sclerotic, their lumens are closed, perivascular fibrosis is noted, and a giant cell reaction is very rare.

Histogenesis. The main role in the development of the disease is given to microangiopathy of various origins, primarily diabetic, with subsequent deposition of lipids. Using the fluorescence reaction, deposition of IgM and C3-component of complement in the walls of blood vessels and in the zone of the dermal-epidermal border in the lesions is detected. Hormonal disorders, activation of free-radical oxidation of lipids, and an increase in the level of lipids in the blood serum of patients are important in the development of microangiopathy. Immunomorphological research with antisera to the S-100 antigen showed a decrease in the number of nerve endings in plaques, which is associated with a decrease in skin sensitivity in these areas.

Treatment of lipoid necrobiosis. It is necessary to identify and treat diabetes mellitus. A diet low in carbohydrates and fats, vascular drugs (nicotinic acid, trental, etc.), antioxidants (lipoic acid, alpha-tocopherol), intralesional injections of corticosteroids and insulin are recommended. Long-term rubbing of corticosteroid ointments, physiotherapy procedures (ultrasound, laser therapy) are used externally.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ]