We report the case of a toddler, with a history of mild atopic dermatitis (AD) since early infancy, presented to the Giannina Gaslini, a pediatric polyclinic hospital, 14 days after measles-mumps-rubella (MMR) vaccination, for the occurrence of a disseminated vesico-pustular rash, accompanied by general malaise, fever, restlessness, and anorexia. Eczema herpeticum (EH) was diagnosed clinically and confirmed by laboratory examinations. The exact pathogenesis of EH in AD is still debated and possibly involves an inter-play between altered cell-mediated and humoral immunity, failure to up-regulate antiviral proteins, and exposure of viral binding sites through the dermatitis and an epidermal barrier failure. We hypothesize that in this particular case, MMR vaccination might have played an additional important role in the alteration of innate immune response, facilitating the manifestation of herpes simplex virus type 1 in the form of EH.

This study aimed to evaluate if patients under biologics have a lower risk of psoriasis flares after coronavirus disease 2019 (COVID-19) vaccination than other psoriatic patients. Of 322 recently vaccinated patients admitted for psoriasis at the Dermatological Psoriasis Unit during January and February 2022, 316 (98%) had no psoriasis flares after COVID-19 vaccination (79% under biologic treatment, 21% not biologically treated) and 6 (2%) presented psoriasis flares after COVID-19 vaccination (33.3% under biologic treatment, 66.6% not biologically treated). Overall, psoriasis patients under biologic treatment, developed fewer psoriasis flares after COVID-19 vaccination (33.3%), than patients not under biologic treatment (66.6%) (p=0.0207; Fisher’s exact test).

We present the case of a 24-year-old Caucasian man, who developed a scaly erythematous skin rash after the second dose of coronavirus disease 2019 (COVID-19) vaccination with Comirnaty (BNT162b2, BioNTech/Pfizer; Pfizer, New York, NY, USA) and proved positive for Epstein-Barr virus (EBV) reactivation. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines have been associated with an up-regulated T helper type 1-cell response, possibly favoring an immune system imbalance. Also, EBV reactivation has been postulated after COVID-19 vaccination, but only in the immunosuppressed. Noteworthy we report the first case of EBV viral reactivation associated with cutaneous manifestations in an immunocompetent patient after the COVID-19 vaccine.

We present the case of a 48-year-old Caucasian woman, who developed an acute urticarial rash after the second dose of coronavirus disease 2019 (COVID-19) vaccination with Oxford-AstraZeneca. Though the most common cutaneous adverse reactions to vaccines are non-allergic, we believe the rash may represent an immediate hypersensitivity type I reaction against the vaccine excipient Polysorbate 80 (Pol80), configuring an acute allergic urticaria. Skin prick test with Pol80, were performed and resulted positive, confirming the role of Pol80 in eliciting immediate hypersensitivity in our patient. Of note, sensitizing excipients contained in COVID-19 vaccines are commonly used in everyday products and preexisting sensitizations may cause allergic reactions to vaccines, highlighting the need to undergo allergy consultation upon vaccine administration.