Assessment of Occipital Involvement Among a Large Population of Females with Pattern Hair Loss in Saudi Arabia.

Background: Cumulative evidence suggests the involvement of the occipital region in female pattern hair loss (FPHL). However, most of the studies that have been published so far concerned relatively small samples of patients. Purpose: To assess the occipital involvement in FPHL and analyze its correlation with disease severity among a large sample of patients. Patients and Methods: A retrospective study involved 1000 adult women with FPHL, between January 2020 and August 2022. Occipital involvement was defined as more than 10% of thin hairs (<0.03 mm). Baseline trichometry parameters in the frontal and occipital regions were analyzed. Results: Occipital involvement was observed in 32.4% of the patients. Positive correlations between frontal and occipital regions were observed for all trichometry parameters; the strongest concerned average hair shaft thickness (Pearson's coefficient r=0.708), cumulative hair thickness (r=0.673), and trichometry-derived Sinclair scale (r=0.656). The risk of occipital involvement increased independently with the disease severity in frontal region; however, the disease progression was slower in the occipital compared to frontal region. Conclusion: One-third of females in our study with FPHL had occipital involvement. This has a major impact on the methods used to diagnose pattern hair loss in females and their treatment plan including hair restoration surgery.