Alopecia in COVID-19 Patients: Systematic Review and Meta-Analysis

The systematic review and meta-analysis of 1826 alopecia patients with COVID-19 from 41 original articles found that several types of alopecia are associated with COVID-19. The patients were classified into different types of alopecia: androgenic alopecia (30.7%), alopecia areata (7.8%), telogen effluvium (19.8%), anagen effluvium (0.1%), pressure-induced alopecia (0.1%), or unclassified (41.4%). It was found that androgenic alopecia often preceded COVID-19 symptoms, suggesting it may be a risk factor for acquiring COVID-19. On the other hand, telogen effluvium, which was usually triggered for the first time by COVID-19 (93.6% of cases), followed COVID-19 symptoms with a mean duration to onset of 56.5 days. Alopecia areata usually occurred as an exacerbation of a pre-existing diagnosis (89.2%) and may occur due to immune dysregulation or loss of immune privilege from infection. The findings are limited by reporting bias.