Histological features of peripilar signs associated with androgenetic alopecia

Background. A study of the scalp in a large cohort of volunteers with androgenetic alopecia using macrophotographs showed the presence of peripilar signs (PPS) around the hair ostia. Objective. The aim of the present study was to establish the histopathological features related to PPS. Design. Prospective clinicopathological study. Setting. Department of Dermatology, University Hospital of Bologna. Patients. A group of 40 patients (21 males and 19 females) participated in the study. Macrophotographs of the scalp were taken using a Dermaphot camera and PPS were scored using a three-point scale. Hair density and PPS were clinically scored according to reference scales. Two punch biopsies from the photographed area were obtained from each subject and histological analysis was performed on vertical and horizontal sections. Observations. Clinical parameters indicated that PPS were already detectable on scalp with high hair density. Moreover, in patients with high hair density (score >4), a significant relationship was found between the PPS score and the global score for perifollicular infiltrates. Thus PPS are linked to superficial perifollicular lymphocytic infiltrates in early androgenetic alopecia. Conclusions. PPS could be the clinical signs reflecting the presence of perifollicular infiltrates.