Exacerbation of Chronic Spontaneous Urticaria Following Coronavirus Disease 2019 (COVID-19) Vaccination in Omalizumab-Treated Patients

BACKGROUND: The rapid development and rollout of vaccines against coronavirus disease 2019 (COVID-19) has led to more than half of the world's population being vaccinated to date. Real-world data have reported various adverse cutaneous reactions, including delayed-onset urticaria, which was highly ranked as a common manifestation across studies. However, the impact of these novel mRNA or viral vector COVID-19 vaccines on preexisting chronic spontaneous urticaria (CSU) remains largely unknown. OBJECTIVE: To investigate the impact of COVID-19 vaccination on the clinical status of patients with relatively stable CSU who are undergoing omalizumab treatment and to identify risk factors for exacerbation. METHODS: We conducted a questionnaire-based cross-sectional study in a tertiary hospital. Adult patients with relatively stable CSU under regular omalizumab treatments who had received at least one COVID-19 vaccination were included. RESULTS: There were 105 study subjects who received 230 COVID-19 vaccinations between March and December 2021. Fifteen patients (14.3%) experienced aggravation of urticaria at least once after COVID-19 vaccination. The demographics and clinical characteristics of the patients were comparable regardless of the exacerbation of CSU. However, case-level analysis revealed that the presence of urticaria (vs none) before vaccination (odds ratio [OR] = 4.99; 95% CI, 1.57-15.82) and the development of systemic reactogenicity (OR = 4.57; 95% CI, 1.62-12.90) were associated with a higher risk for exacerbation. CONCLUSIONS: The novel COVID-19 vaccination induced exacerbation in more than one-tenth of patients with well-controlled CSU. The establishment of a proper management strategy during COVID-19 vaccination is necessary for patients with CSU.