Decalvating folliculitis is a rare dermatosis with a predominant lesion of the scalp. It is characterized by purulent inflammation of the hair follicles, chronic recurrent and progressive persistent hair loss. The clinical and histopathological picture of decalvating folliculitis is often nonspecific that leads to the emerging diagnostic difficulties. We present a review of the literature highlighting the etiology and pathogenesis, clinical and dermatoscopic manifestations, features of the histopathological picture, as well as a description of the clinical case. The clinical picture was characterized by follicular papules and pustules, bundles of hair, foci of cicatricial alopecia; dermatoscopically revealed follicular pustules, a sign of «star burst», bundles of hair, tubular peeling, concentrically located around the hair follicles of the loops of blood vessels; Staphylococcus aureus was detected during bacteriological examination of the pustules’ content. Histopathological examination revealed hyperkeratosis, acanthosis, vacuolar degeneration of the spiny layer cells, dilated hair funnels filled with stratum corneum. Perifollicular and perivascular infiltration with lymphocytes, neutrophils, macrophages, and single plasmocytes was observed in dermis. Large foci of granulomatous inflammation were revealed. In the center of these foci, hair shafts are visible, devoid of epithelial sheaths, surrounded by dilapidated hair follicles and significant lymphohistiocytic infiltration with single giant cells. Pronounced fibrosis were detected around these foci. The pathological picture made it possible to classify the disease as neutrophilic cicatricial alopecia. On a clinical example, it is shown that in the diagnosis of decalvating folliculitis it is necessary to compare clinical and anamnestic, laboratory and pathological data.