32731 Alopecia in COVID-19 patients: Systematic review and meta-analysis

Abstract

Objective: We conducted a systematic review to summarize the types, incidence, timing, and clinical outcomes of COVID-19-associated alopecia. Methods: We searched PubMed/MEDLINE, Embase, and Scopus for articles published between November 2019 and August 2021 using keywords “alopecia” or “hair” and COVID-19 search terms adapted from the MLA Clinical Librarians Caucus’ COVID-19 hedge, identifying 262 distinct reports, subsequently screened to 41 original articles describing alopecia patients with COVID-19. Results: This review summarizes findings from 1826 alopecia patients with COVID-19 (mean age 54.5 years, 55.9% male) from 19 case series, 11 case reports, 5 cross-sectional studies, 4 cohort studies, and 2 case-control studies. Patients from 17 countries were classified as androgenic alopecia (30.7%, mean age 61.1, 86.4% male), alopecia areata (7.8%, mean age 36.1, 40% male), telogen effluvium (19.8%, mean age 48.0, 19.3% male), anagen effluvium (0.1%, mean age 29.5, 0% male), pressure-induced alopecia (0.1%, mean age 43.0, 100% male), or unclassified (41.4%, mean age 51.5, 15.3% male). Androgenic alopecia preceded COVID-19 symptoms, whereas telogen effluvium followed COVID-19 symptoms (mean duration to onset 56.5 days). Telogen effluvium was usually triggered for the first time by COVID-19 (93.6%), whereas alopecia areata usually occurred as an exacerbation of a pre-existing diagnosis (89.2%). Conclusion: Several types of alopecia are associated with COVID-19, though our findings are limited by reporting bias. Androgenic alopecia may be a risk factor for acquiring COVID-19, whereas telogen effluvium is likely triggered by infection-related metabolic stress. Alopecia areata may occur due to immune dysregulation or loss of immune privilege from infection.