Local injection site reactions are the most common skin reaction associated with Covid-19 vaccines, according to results of a large Spanish study, reported in the British Journal of Dermatology.¹ The study also identified six most common patterns of skin reactions.

A multicenter observational study was conducted with the aim to describe the clinical features of skin reactions following vaccination with any Covid-19 vaccine. All patients who had been vaccinated and developed a skin reaction within 21 days of receiving a vaccine dose, between February 16 and May 15, 2021, were enrolled in the study. Their mean age was 50.7 years and the majority of participants were female (80.2%). An online survey was used to gather information about the skin reactions and clinical images of the skin lesions were procured via email. Patients in whom a cause could be identified and those who had injection-site reactions for less than 3 days were excluded from the study.

A total of 405 post-vaccine skin reactions were collated. Of these, 40.2% had occurred after taking the Pfizer-BioNTech vaccine, 36.3% after vaccination with Moderna vaccine, while 23.5% skin reactions were reported after the AstraZeneca vaccine.

Six major groups of skin reactions were identified: local injection site reactions or “COVID arm” (32.1%), urticaria and/or angioedema (14.6%), morbilliform rash (~9%), papulovesicular or pseudovesicular (6.4%), pityriasis rosea-like (~5%) and purpuric rashes (4%). Around 14% of skin reactions were reactivation of varicella zoster and herpes simplex virus. Covid arm was most commonly reported among women (95·4%).

When the skin reactions were categorized according to the vaccine, the most frequent skin reaction in the Moderna vaccine group was Covid arm (62%); in the Pfizer-BioNTech group, varicella zoster virus reactivation was the most common cutaneous reaction (17%), while urticaria was the commonest skin reaction encountered in the AstraZeneca group (21.1%). Most were self-resolving, while 21% were severe and very severe and 81% needed treatment.

This study has characterized the skin reactions associated with three Covid-19 vaccines. While the majority were mild to moderate in severity, few of them were severe to very severe, which required treatment. Awareness about these associations may help physicians to anticipate these skin reactions and reassure patients.

Reference

1. A Català, et al. Cutaneous reactions after SARS-CoV-2 vaccination: a cross-sectional Spanish nationwide study of 405 cases. Br J Dermatol. 2022 Jan;186(1):142-152. doi: 10.1111/bjd.20639.