Tufted folliculitis of the scalp: a distinctive clinicohistological variant of folliculitis decalvans.

Tufted folliculitis is an uncommon folliculitis of the scalp that resolves with patches of scarring alopecia within which multiple hair tufts emerge from dilated follicular orifices. The clinicohistological data from a group of 15 patients with tufted folliculitis were reviewed and compared with those of seven patients with folliculitis decalvans, five with acne keloidalis nuchae, four with dissecting cellulitis of the scalp, three with kerion celsi and 20 with follicular lichen planus. It was found that tufted folliculitis could be differentiated from folliculitis decalvans only by finding several hair tufts scattered within patches of scarring alopecia. Histologically, a single tuft consisted of peculiar clustering of adjacent follicular units opening at the bottom of an epidermal depression. Conversely, the presence of keloidal plaques in acne keloidalis nuchae, coalescing nodules discharging purulent material in dissecting cellulitis of the scalp, erythematous plaques covered by pustules replete with fungal elements in kerion celsi, and the absence of follicular pustules in follicular lichen planus distinguished these diseases from tufted folliculitis. On the basis of these findings, it is suggested that tufted folliculitis should be considered as a distinctive clinicohistological variant of folliculitis decalvans. Tufting of hair is caused by clustering of adjacent follicular units due to a fibrosing process and to retention of telogen hairs within the involved follicular units.