Development of Multiple Cherry Angiomas in a Child after COVID-19 Vaccination

Vaccination has played a crucial role in the improvement of global health. Some of the world's deadliest diseases like smallpox and rinderpest have been eradicated with the help of vaccines and many others have been restrained. The appearance of the strain of coronavirus SARS-CoV-2 and its impact on global health have made crucial the development of effective and safe vaccines for this new lethal disease. So far, there are three main types of COVID-19 vaccines in use around the world: mRNA-based vaccines, adenoviral vector vaccines, and inactivated whole-virus vaccines. Some of them have passed through phase 3 safety and efficacy trials and are widely used for prophylaxis of the coronavirus infection. A plethora of cutaneous adverse events have been reported, most of them mild or moderate injection site reactions. Some rare delayed inflammatory reactions such as "COVID arm" have been reported posing questions on their pathophysiology and their clinical importance. Some rare serious adverse events such as VIPIT and anaphylaxis have been described raising great concerns on the safety of some widely spread vaccines. More data need to be collected with further and more detailed analysis. Still, the overall risk of those severe adverse reactions remains extremely low and the benefits of the existing vaccines in combating the widespread threat of COVID-19 continue to outweigh the risk of their side effects.

(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.