Increased Risk of Developing Alopecia Areata Seen Following COVID-19 Infection

January 12, 2024

Alopecia areata is an autoimmune hair loss condition thought to be caused by a combination of genetic susceptibility and an external trigger such as viruses, vaccinations, or psychological stress. A research letter published this week discussed a study aimed to explore the association between COVID-19 infection and alopecia areata, given that COVID-19 infection has been previously found to trigger other autoimmune diseases such as systemic lupus erythematosus, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), and rheumatoid arthritis.

Conducted from October 8, 2020, to September 30, 2021, the nationwide, population-based cohort study involved 259,369 COVID-19 patients and an equal number of uninfected controls. Results indicated a significant increase in the incidence and prevalence of alopecia areata after COVID-19 infection, regardless of clinical subtype, even after adjusting for confounding factors. The risk was elevated in all age groups over 20 years, with higher susceptibility among both females and males.

Plausible explanations provided for the correlation included molecular mimicry between SARS-CoV-2 and hair follicle autoantigens, cytokine shifting (fluctuations in cytokine levels during an immune response), and bystander activation (activation of immune cells that were not directly involved in the initial immune response but become activated as a consequence of nearby immune activity). The study concluded by emphasizing the need for further research to validate the association across different populations and elucidate the causal relationship between COVID-19 and alopecia areata.