Background Cutaneous reactions after mRNA-based COVID-19 vaccines have been reported but are not well characterized. Objective To evaluate morphology and timing of cutaneous reactions after mRNA COVID-19 vaccines. Methods A provider-facing registry-based study collected cases of cutaneous manifestations after COVID-19 vaccination. Results From December 2020-February 2021, we recorded 414 cutaneous reactions to mRNA COVID-19 vaccines from Moderna (83%) and Pfizer (17%). Delayed large local reactions were most common, followed by local injection site reactions, urticarial eruptions, and morbilliform eruptions. Forty-three percent of patients with first dose reactions experienced second dose recurrence. Limitations Registry analysis does not measure incidence. Morphologic misclassification is possible. Conclusion We report a spectrum of cutaneous reactions after COVID-19 mRNA vaccines. Most patients with first dose reactions did not develop a second dose reaction, and no patients in the registry developed serious adverse events after the first or second dose. These data provide reassurance to patients and providers.

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Background: Cutaneous reactions after COVID-19 vaccination have been commonly reported; however, histopathologic features and clinical correlations have not been well characterized. Methods:We evaluated for a history of skin biopsy all reports of reactions associated with COVID-19 vaccination identified in an international registry. When histopathology reports were available, we categorized them by reaction patterns.Results: Of 803 vaccine reactions reported, 58 (7%) cases had biopsy reports available for review. The most common histopathologic reaction pattern was spongiotic dermatitis, which clinically ranged from robust papules with overlying crust, to pityriasis rosea-like eruptions, to pink papules with fine scale. We propose the acronym ''V-REPP'' (vaccine-related eruption of papules and plaques) for this spectrum. Other clinical patterns included bullous pemphigoid-like (n = 12), dermal hypersensitivity (n = 4), herpes zoster (n = 4), lichen planus-like (n = 4), pernio (n = 3), urticarial (n = 2), neutrophilic dermatosis (n = 2), leukocytoclastic vasculitis (n = 2), morbilliform (n = 2), delayed large local reactions (n = 2), erythromelalgia (n = 1), and other (n = 5).Limitations: Cases in which histopathology was available represented a minority of registry entries. Analysis of registry data cannot measure incidence.