Case series of chronic spontaneous urticaria following COVID-19 vaccines: an unusual skin manifestation.

Background: Urticaria following the COVID-19 vaccine was rarely reported and had a short self-limited resolution. However, there has been relatively little literature published on CSU induced by COVID-19 vaccines.

Purpose: We describe a case series of patients who experienced CSU after SARS-CoV-2 vaccination.

Methods: A retrospective case series of 10 patients referred to the Department of Clinical Pharmacology of the University of Monastir (January 2021-January 2022) and included for evaluation of urticaria after COVID-19 vaccination.

Results: The median age was 31 years and patients were mostly female. Atopy was presented in 3 patients and urticaria was accompanied by angioedema in 6 patients. The median time interval between vaccination and the onset of urticaria was 28.5 h. The offended dose was the first one in 8 patients. The resolution of the eruption was observed at least 2 months later, despite the regular use of a full dose of antihistamine in nine patients. Polynuclear leucocytosis was identified in 5 patients. Anti-TPOAb was positive in one patient after receiving the BNT162b2 vaccine. Total serum IgE was elevated in 4 patients. Skin tests for the suspected vaccine as well as the vaccine excipient were negative.

Conclusion: We add to the medical literature ten new cases of chronic spontaneous urticarial reactions following COVID-19 vaccines uncontrolled with high-dose first-generation H1 antihistamines.