Reply to: "Herpes zoster seven days after SARS-CoV-2 vaccination in a patient with ankylosing spondylitis under adalimumab" by Josef Finsterer.

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Erythema nodosum after COVID-19 vaccine.

The current coronavirus disease 2019 (COVID-19) pandemic is a global challenge with strong medical and socioeconomic implications. Hopes have been placed in the development of various vaccines. As the vaccination campaign is in progress, adverse effects need to be monitored closely. Possible side effects range from minor events to more serious manifestations. In this article, we describe two cases of erythema nodosum (EN) after COVID-19 vaccination in two previously healthy female patients of 59 and 51 years, respectively. Most of the usual etiologies of EN were excluded by laboratory testing. EN was successfully treated with corticosteroids. Remarkably, in the first case, a relapse occurred 48 hours after the second dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. In this case series, we describe two unusual occurrences of EN after vaccination with an mRNA COVID-19 vaccine and a viral vector vaccine, respectively, and we discuss the available related literature.

Herpes zoster infection following mRNA COVID-19 vaccine in a patient with ankylosing spondylitis.

Since the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) pandemic outbreak, vaccines gained a growing role. Possible vaccine-related side effects range from minor local events to more prominent systemic manifestations up to anaphylactic reactions. A heterogeneous spectrum of cutaneous reactions has been reported, ranging from local injection site reactions to urticarial and morbilliform eruptions, pernio/chilblains and zoster flares. Here, we describe a case of varicella zoster virus reactivation following mRNA coronavirus 2019 vaccine and discuss the available literature upon the topic published so far.