(1) Background: Numerous vaccines are under preclinical and clinical development for prevention of severe course and lethal outcome of coronavirus disease 2019 (COVID-19). In light of high efficacy rates and satisfactory safety profiles, some agents have already reached approval and are now distributed worldwide, with varying availability. Real-world data on cutaneous adverse drug reactions (ADRs) remain limited. (2) Methods: We performed a literature research concerning cutaneous ADRs to different COVID-19 vaccines, and incorporated our own experiences. (3) Results: Injection site reactions are the most frequent side effects arising from all vaccine types. Moreover, delayed cutaneous ADRs may occur after several days, either as a primary manifestation or as a flare of a pre-existing inflammatory dermatosis. Cutaneous ADRs may be divided according to their cytokine profile, based on the preponderance of specific T-cell subsets (i.e., Th1, Th2, Th17/22, Tregs). Specific cutaneous ADRs mimic immunogenic reactions to the natural infection with SARS-CoV-2, which is associated with an abundance of type I interferons. (4) Conclusions: Further studies are required in order to determine the best suitable vaccine type for individual groups of patients, including patients suffering from chronic inflammatory dermatoses.

(1) Background: Coronavirus disease 2019 (COVID-19) vaccines are currently employed on a population-wide scale in most countries worldwide. Data about unusual cutaneous adverse drug reactions (ADR) are scant, though. (2) Methods: We retrospectively analyzed moderate to severe vaccine-related ADR in the Department of Dermatology and Allergy of the University Hospital Bonn between May to June 2021 and analyzed related skin biopsies. (3) Results: As a specialized dermatological academic center, we encountered a total of n = 19 clinically and pathologically heterogeneous cutaneous ADR with a female predominance. Delayed cutaneous ADR occurred as late as 30 days after vaccination. The majority of ADR were mild, though a few patients required systemic treatment (antihistamines, glucocorticosteroids). (4) Conclusions: The clinico-pathological spectrum of cutaneous side effects with COVID-19 vaccines is wide; however, the benefits outweigh the risks by far. More dermatopathological studies on cutaneous ADR not limited to COVID-19 vaccines are desirable to enable a better understanding of underlying pathophysiological mechanisms.

Effective vaccines for prevention of severe course and lethal outcome of coronavirus disease 2019 have been developed and approved in regulatory rolling and fast‐track procedures; they are now widely distributed worldwide. Data about cutaneous side‐effects of the new mRNA‐type vaccines is scant, however. We herein report two similar cases of cutaneous adverse drug reactions (ADR) mimicking Rowell’s syndrome that occurred after the first dose of BNT162b2 and mRNA‐1273, respectively. Both patients achieved prompt clinical improvement with a short pulse of oral prednisolone and non‐steroidal inflammatory drugs. We suspect this phenomenon to occur in a timeframe of 7–14 days after vaccination due to an interferon‐γ‐driven shift towards type I immunity in susceptible individuals. As rheumatic patients were excluded from phase III clinical trials and as most countries prioritized the elderly population to receive the vaccinations first, cutaneous ADR might become more frequent once the younger part of the population is vaccinated over the course of 2021. Atypical cutaneous ADR might be misinterpreted or overlooked by non‐dermatologists. Further studies are required to determine the best suitable vaccine types for individual groups of patients.

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