The clinical and pathologic spectrum of mucocutaneous reactions following COVID-19 vaccines in three tertiary referral centers of Northern Italy

: Adverse cutaneous reactions following COVID-19 vaccines have increased, highlighting not only how SARS-CoV-2 infection but also COVID-19 vaccines may induce adverse cutaneous manifestations. We evaluated the clinical and pathologic spectrum of mucocutaneous reactions following COVID-19 vaccines, observed consecutively within three large tertiary Centers of the Metropolitan City of Milan (Lombardy), comparing our results with the currently available literature. We retrospectively reviewed medical records and skin biopsies of patients diagnosed with mucocutaneous adverse events following COVID-19 vaccines and followed at 3 Italian tertiary referral centers in the Metropolitan City of Milan. One hundred twelve patients (35M:75 F; median age 60 years) have been included in the current study; a cutaneous biopsy was performed in 41 cases (36%). The trunk and arms were the most involved anatomic areas. Autoimmune reactions following COVID-19 vaccines, urticaria, morbilliform eruptions, and eczematous dermatitis have been the most commonly diagnosed disorders. Compared to the currently available literature, we performed many more histologic examinations, allowing us to make more precise diagnoses. Most of the cutaneous reactions were self-healing and/or responded to topical and systemic steroids and systemic antihistamines, thus not discouraging the general population from carrying out vaccines, which currently have a good safety profile.