Comorbidity Burden in Frontal Fibrosing Alopecia and Lichen Planopilaris: A Systematic Review and Prevalence Meta-Analysis

Background/Objectives: Frontal fibrosing alopecia (FFA) and lichen planopilaris (LPP) are primary lymphocytic cicatricial alopecias with frequently reported systemic and dermatological comorbidities, although their prevalence and consistency across studies remain uncertain.

Methods

We conducted a systematic review and random-effects prevalence meta-analysis following PRISMA 2020 and Joanna Briggs Institute guidance, prospectively registered in PROSPERO (CRD420250656067). MEDLINE, Embase, ClinicalTrials.gov, preprint sources, and reference lists were searched from inception to 18 June 2025 for observational studies reporting comorbidity prevalence in FFA and/or LPP.