Simple chronic lichen: causes, symptoms, diagnosis, treatment

Lichen simplex chronicus (synonyms: limited neurodermatitis, limited neurodermatitis, limited atopic dermatitis, itchy lichenoid dermatitis, Vidal's lichen, limited chronic simple prurigo).

The term neurodermatitis (syn: neurodermatitis) was introduced by Brocq in 1891 to denote skin diseases in which skin changes develop as a result of scratching caused by primary itching.

Therefore, primary itching is a characteristic symptom of neurodermatitis. Limited neurodermatitis affects almost exclusively adults. Men suffer from this form somewhat more often than women. Dermatologists often use the term limited neurodermatitis. Many dermatologists distinguish limited neurodermatitis from atopic neurodermatitis not only by clinical manifestations, but also by etiology and pathogenesis.

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What causes lichen simplex chronicus?

The main pathogenetic factor is increased sensitivity of the skin to irritants, apparently due to the proliferation of nerve endings, and a predisposition to epidermal hyperplasia in response to mechanical trauma. Functional disorders of the nervous and endocrine systems, allergic conditions of the body, and gastrointestinal diseases play an important role in the development of the disease. Hereditary predisposition is also indicated.

Symptoms of Lichen Simplex Chronicus

The disease begins with itching of the skin. Symptoms of simple chronic lichen are localized mainly on the back and side surfaces of the neck, in the popliteal and elbow folds, anogenital area, on the inner surface of the thighs, in the intergluteal folds. But lesions can also appear on other areas of the skin, including the scalp. At the beginning, the skin in the areas of itching is externally unchanged. Over time, under the influence of scratching, polygonal papules of a dense consistency appear, in places covered with flour-like scales. Papules merge and form oval or round plaques, which have a color from pink to brownish-red. The skin thickens, becomes rough, and a skin pattern (lichenification) is expressed. At the height of the disease development, three zones are distinguished in the lesion. The peripheral or outer zone of pigmentation surrounds the lesion in the form of a belt and usually neither the outer nor the inner borders are clear. The middle, papular zone consists of nodular rashes of pale pink, grayish or yellowish color, the size of a pinhead to a small lentil. The papules are irregular in shape and not sharply defined, almost not rising above the surrounding skin. Their surface is thickened, smooth and as a result of scratching often covered with a bloody crust. The inner zone is characterized by pronounced infiltration of the skin. Often this zone is the only manifestation in the clinical picture of the disease.

Irrational and untimely treatment of candidal vulvovaginitis leads to its long-term course, and constant itching of the genitals contributes to the development of lichenification. In sick women, limited neurodermatitis of the external genitals may develop in the future. The author observed the development of limited neurodermatitis of the external genitals after long-term irrational treatment of candidal vulvovaginitis.

In the practice of a dermatovenerologist, the following atypical and rare types of limited neurodermatitis are often encountered:

Depigmented neurodermatitis. With prolonged limited neurodermatitis, secondary hypopigmentation (vitiligo-like changes) occurs. They are believed to appear as a result of scratching. In this case, it often seems that there is a combination of two processes - neurodermatitis and vitiligo.

Hypertrophic (warty) neurodermatitis. In this form, against the background of the typical clinical picture of limited neurodermatitis, there are separate nodular and even nodular rashes, very similar to those in nodular pruritus. Such lesions occur mainly on the inner surfaces of the thighs, but can also be localized in any other areas.

As a result of severe itching of the scalp, hair falls out, the skin becomes thinner, shiny, but not atrophic, the process is not associated with the follicular apparatus. This form of the disease is called decalvans neurodermatitis.

Acute follicular neurodermatitis is characterized by the follicularity of the rash and its pointed shape.

Linear neurodermatitis manifests itself in the form of rather long stripes of varying width of lichenification. Individual nodules are often much larger in size than in ordinary limited neurodermatitis. The lesions are most often localized on the extensor surfaces of the extremities.

Histopathology. In the epidermis, intracellular edema of the spinous cells, hyperkeratosis, parakeratosis, and acanthosis are observed. Spongiosis is weakly expressed. In the dermis, the papillae are edematous, elongated and dilated, and the argyrophilic fibers are thickened. The infiltrate consists of lymphocytes and a small number of fibroblasts and leukocytes, located mainly around the vessels of the papillary layer.

Treatment of simple chronic lichen

Treatment of simple chronic lichen consists of a thorough clinical and laboratory examination and the elimination of identified concomitant diseases, and adherence to a strict diet. Of the medications used are psychotropic, weak neuroleptics, antihistamines (tavegil, fenistil, diazolin, etc.), externally - corticosteroids (betiovate, elocom, etc.) and itching (fenistil gel, 1% diphenhydramine, 0.5-2% anesthesin, 1-2% menthol) ointments. In case of a torpid course, the lesions are injected with triamcinolone at a concentration of 3 mg / ml and occlusive dressings are applied over the corticosteroid ointment.