Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Dermatology and Venerology

Background: Androgenetic alopecia (AGA) is a very common type of hair loss.Trichoscopy plays an important role in its diagnosis and a scalp biopsy is seldom needed. Peripilar sign is a trichoscopic sign first described in AGA and is said to reflect the presence of perifollicular infiltrate (PFI) in histopathology.Objective: To assess as a primary outcome the validity of the PPS as a sign indicative of PFI in a cohort of AGA.Secondary outcomes included studying PPS and PFI and the different factors affecting them. Methods: Hundred Egyptian patients with AGA were recruited in this observational analytical cross-sectional study. All cases were confirmed to have AGA by trichoscopy. Scalp biopsy was done for two subgroups, 22 patients with PPS and 23 patients without PPS. Both groups were compared as regards the presence of PFI.Results: Peripilar sign was present in 50% of the studied cases.No significant difference existed between those with and those without PPS as regards PFI. Peripilar sign was significantly more encountered in lighter skin types (p=0.001). Its absence was significantly associated with the absence of yellow dots (p<0.001) and their scores were significantly positively correlated (r=0.498, p<0.001). Peripilar sign was significantly associated with absent melanophages (p=0.011). Perifollicular infiltrate was detected in 82.2% of studied biopsies around the infundibulum of hair follicles. It was significantly associated with perifollicular fibrosis (p<0.001) and their scores were significantly positively correlated (r=0.594, p<0.001)

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