Clinicopathological features of cutaneous reactions after mRNA-based COVID-19 vaccines.

BACKGROUND: Cutaneous reactions, mostly on injection site after mRNA-based COVID-19 vaccines, have been reported but not with detailed histopathological characterization. OBJECTIVES: Characterization and classification of these reactions in a clinical and pathological point of view. METHODS: Monocentric case series of 11 patients with cutaneous manifestations, clinically and histologically characterized after COVID-19 vaccination. RESULTS: From January to June 2021, we recorded 11 cutaneous reactions to mRNA COVID-19 vaccines from BNT162b2 (n = 8) and mRNA-1273 (n = 3). Generalized reactions showing erythematous rash or purpura were the most common clinical presentation, and drug-reaction-like pattern was the most common histological finding. CONCLUSIONS: A proper clinicopathological classification will be helpful in the early diagnosis and management of the cutaneous reactions to mRNA COVID-19 vaccines.