Atrophic form of red flat lichen as a cause of alopecia

This rare clinical form of red flat lichen is, according to various authors, from 2% to 10% of all forms of dermatosis. It is manifested by flat, slightly elevated papules of pale pinkish-cyanotic color as large as lentils, which sometimes form ring-shaped foci. On the ground initially papular rashes, characteristic for red flat lichen, form a small clearly delineated atrophic areas of the skin, somewhat sinking in relation to the surrounding skin and deprived of hair and hair follicle openings. Typically, not all papules of red lichen planus undergo this transformation; part of the typical rash for this dermatosis is coiled on the skin, visible mucous membrane of the mouth and on the genitals. In some cases, there is also a characteristic nail dystrophy. Atrophic foci on the skin are the final stage in the evolution of papules of red flat lichen, i.e. Arise again, which greatly facilitates the clinical diagnosis of this form of dermatosis. Eruptions are more often located on the skin of the trunk, genitals, limbs, as well as the scalp, where the state of the pseudo-peluda is formed. Vysypnye elements often appear in a small amount, but can be grouped and merged into larger, clearly delineated areas of skin atrophy with pigmentation, less often - depigmentation. Atrophic skin changes often occur within the ring-shaped foci, which may be the only manifestation of dermatosis or associated with the rashes described above. Ring-shaped lesions usually have a small diameter (about 1 cm) and can gradually increase in size, reaching 2-3 cm. Their central part is sharply outlined, smooth, atrophic, unevenly pigmented; peripheral - is represented by an elevated, continuous brownish-cyanotic rim, surrounding the atrophic brownish center. Many authors note a prolonged, stubborn course of the ring-shaped atrophic red flat lichen.

Histopathology

The epidermis is atrophic, thinned, the epithelial outgrowths are smoothened, hyperkeratosis and hypergranulosis are less pronounced than in the typical form. Dermal papillae absent, characteristic for the usual form of a band-shaped infiltrate in the dermis is rare, more often it is perivascular, sometimes quite lean, consisting mainly of lymphocytes; proliferation of histiocytes in the subepidermal sections. Always, although with difficulty, you can find "washed out" cells of the infiltrate separate areas of the lower boundary of the basal layer; In the field of infiltration, elastic fibers are almost completely absent.

Diagnostics

On the scalp, the foci of atrophic red flat lichen are differentiated with other dermatoses that lead to the condition of the pseudo-peloid. Secondarily arising on the skin of the trunk and extremities, small areas of atrophy of the size of lentils are clinically very similar to manifestations of small-scleroderma scleroderma, or sclerotrophic lichen. With rare localization on the scalp, it can also lead to a pseudo-peloid. In cases where, in addition to the pseudo-pellicle and small foci, atrophy in other parts of the skin or mucous membrane shows typical manifestations of red flat lichen, the diagnosis is facilitated. Decisive are the results of the histological examination of the affected skin, which in these dermatoses differ significantly.

Ring-shaped foci of atrophic red flat lichen may resemble cicatricial cicatrices, Bowen's disease, sometimes discoid lupus erythematosus, annular granuloma, with localization in the nape of the neck, posterior and lateral surfaces of the neck- elastosis perforating serpiginating, and on the genitals - orbicular syphilide.

It should also take into account the rare possibility of developing a basal cell epithelioma of the skin on the scalp, reminiscent of focal scleroderma (sclerodermiform basalioma). Also, metastases are rarely found in the skin of the scalp. They develop in people who have had previous surgical treatment of breast cancer or other localization, and can manifest themselves as sclerosing foci of alopecia. If a neoplastic process is suspected, a histological examination of the skin should be performed.

[1], [2], [3], [4], [5], [6], [7], [8], [9]