Cutaneous Adverse Reactions to COVID-19 Vaccines: Insights from an Immuno-Dermatological Perspective.

(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.