Adverse Cutaneous Reactions Following COVID-19 Vaccination Among Patients with Pre-Existing Urticaria: A...

To investigate the incidence, characteristics, and associated factors of cutaneous adverse reactions to COVID-19 vaccines among adult patients with pre-existing urticaria in Saudi Arabia.

A cross-sectional study enrolled 190 adult patients (≥18 years) with urticaria attending allergy/dermatology clinics at King Khalid University Hospital, Riyadh (November 2021-April 2022). Data on demographics, urticaria characteristics, vaccination status, cutaneous reactions, and comorbidities were collected via questionnaire. Statistical analyses included descriptive statistics, Chi-square/Fisher exact tests, Cochran's test, and binary logistic regression.

Participants were predominantly female (87.4%), with chronic spontaneous urticaria (97.9%); 78.9% used regular antihistamines. Reactions occurred after dose 1 (22.7%), dose 2 (26.2%), and dose 3 (31.0%). Among symptomatic individuals, onset was typically <24h, resolving in 1-3 days for ~50%. Common reactions included injection site reactions (13.1-16.3%), pruritus (7.8-10.5%), and urticaria exacerbation (3.9-9.1%). Urticaria exacerbation decreased significantly after dose 3 (p=0.030). Regular antihistamine use was associated with fewer reactions after dose 1 (adjusted OR 0.4, p=0.028). Female gender, asthma/atopy, and autoimmune disease were associated with specific reactions. Adjusted vaccine type showed no significant association.

Cutaneous reactions post-COVID-19 vaccination in urticaria patients are relatively common but generally mild and transient. Decreasing urticaria exacerbations after dose 3 is reassuring. Regular antihistamine use may offer some protection, particularly after the first dose. Findings support vaccine safety and aid patient counseling.