Alopecia Areata: COVID Infections and COVID Vaccines Can Both Act as Triggers

Authors from Italy present six cases of AA. 3 cases occurred after SARS-CoV-2 infection, and 3 began after COVID-19 vaccination

Alopecia Areata After COVID 19 Infection

The three patients (2 females and 1 male) who developed alopecia areata after COVID 19 infection were aged 28-56 years. They developed patchy AA about 2-3 weeks after infection. None of these 3 patients required hospitalization. Only one of the patients a previous episode of a single patch of AA on the scalp 4 years before. All patients applied local corticosteroids and underwent spontaneous resolution within 4 months.

Alopecia Areata After COVID 19 Vaccination

The authors also reported 3 patients who developed widespread AA following 1-2 weeks after the first dose of the COVID vaccine. 2 had the Pfizer/BioNTech mRNA vaccine and had the Moderna mRNA vaccine. 2 of the patients had a prior history of alopecia areata one of which progressed to alopecia totalis that was refractory to treatment.

Overall, the authors presented cases of AA happening in association with COVID 19 infection and COVID 19 vaccination. The extent of hair loss (median SALT score) was greater in those whose AA happened post-vaccination as opposed to natural infection. SALT score was 56 ± 38.9 in the vaccination group and 10.6 ± 7 in the infection group.

Conclusion/ Comments

There is mounting evidence that in some patients, both COVID 19 infections and COVID 19 vaccination can trigger alopecia areata. The exact incidence is unknown but likely not common. The infection itself is known to drive a variety of inflammatory changes in the body (cytokine storm) which set up an inflammatory environment that facilitates the development of alopecia areata in those who have an underlying susceptibility. The mechanisms for vaccine induced AA are also not clear but the vaccine triggers molecular mimicry and and immune response to both hair follicle antigens and Sars-COV-2 antigens. It has been prosed that the vaccine might prompt an antibody-mediated response that may cross-react with self-antigen, leading to autoimmunity. The risk factors are not clear.

REFERENCE

Bardazzi et al. New insights on alopecia areata during COVID-19 pandemic: when infection or vaccination seems to play a role. J Cosmet Dermatol. 2022 Feb 18