Comorbidities of Primary Scarring Alopecias: A Retrospective Multi‐Site Cross‐Sectional Study

ABSTRACT Background To date, limited research has compared the systemic comorbidities of primary scarring alopecia types. Such research may provide insight into shared disease mechanisms, elucidate novel pathways for therapeutics, and identify those most at risk of comorbidities. Objectives To evaluate the prevalences of systemic comorbidities among scarring alopecia types and compare the prevalence of these comorbidities with national United States prevalence. Methods A retrospective chart review was conducted investigating the systemic comorbidities in patients with scarring alopecia seen at public and private dermatology clinics in Los Angeles between 2018 and 2022. Results A total of 240 patients were identified. Compared to other scarring alopecia types, patients with central centrifugal cicatricial alopecia (CCCA) had an increased risk for concomitant traction alopecia (OR 13.98, p < 0.001), concomitant androgenetic alopecia (OR 3.40, p < 0.001), and vitamin D deficiency (OR 1.97, p = 0.039). Compared to the general US population, patients with scarring alopecia, including CCCA and lichen planopilaris/frontal fibrosing alopecia, had a higher prevalence of vitamin D deficiency, metabolic syndrome, depression, anxiety, thyroid disease, uterine fibroids, anemia, atopy, androgenetic alopecia, and breast cancer. Conclusions Larger, prospective, population‐based studies involving diverse patient groups are needed to differentiate the rates of comorbidities across scarring alopecia types. Dermatologists should consider a thorough review of systems in their patients with scarring alopecia to screen for associated comorbidities, encourage patients to be up to date with age‐appropriate screenings, and consider treatment plans that treat associated dermatologic comorbidities along with the primary scarring alopecia.