Association between COVID-19 and exacerbation of allergic skin diseases

Coronavirus disease 2019 (COVID-19) has been linked to systemic immune dysregulation and various cutaneous manifestations, but its association with chronic allergic skin diseases, including atopic dermatitis (AD) and chronic urticaria (CU), remains unclear. This retrospective questionnaire-based cross-sectional study enrolled patients with AD and/or CU from a tertiary dermatology outpatient center in Western China. Self-administered questionnaires collected data on COVID-19 infection status, clinical characteristics, medication use, and self-reported changes in disease status within 14 days of COVID-19 symptom onset or diagnosis. Outcomes were self-reported rather than based on validated severity scores, and no prospective longitudinal follow-up was performed. Multivariable logistic regression analyses were conducted to identify factors associated with self-reported exacerbation. Covariates were selected a priori based on clinical relevance, and no missing data were present. A total of 509 patients with AD and/or CU were included. Compared with the non-COVID-19 group, participants with COVID-19 more frequently reported current alcohol consumption, pre-COVID-19 antihistamine use, insomnia, allergic rhinitis, and discontinuation of dermatological medications. COVID-19 infection was associated with self-reported exacerbation of allergic skin diseases in both the baseline-adjusted model (odds ratio [OR] = 4.611, 95% confidence interval [CI] = 2.268-9.377) and the fully adjusted model (OR = 4.445, 95% CI = 2.159-9.151). Among participants with COVID-19, fever, headache, fatigue, taste loss, reported use of antipyretics and antibiotics, and nervousness differed between the exacerbation and non-exacerbation groups. After multivariable adjustment, fatigue (OR = 1.601, 95% CI = 1.049-2.443), taste loss (OR = 1.654, 95% CI = 1.004-2.723), and the reported use of antibiotics (OR = 1.609, 95% CI = 1.036-2.499) and antipyretics (OR = 1.575, 95% CI = 1.037-2.392) were associated with self-reported exacerbation, although the medication-related associations likely reflected confounding by indication. Sensitivity analyses yielded consistent results. In this retrospective questionnaire-based cross-sectional study conducted during the omicron wave, COVID-19 infection was associated with self-reported exacerbation of AD and CU within 14 days of symptom onset or diagnosis. Because the outcome was based on participants' recall of symptom change rather than objective clinical assessment, the findings should be interpreted with caution, and their generalizability is limited by the single-center, omicron-period design. Associations with antipyretics and antibiotics likely reflect confounding by indication rather than direct pharmacological effects. Prospective multicenter studies with standardized outcome measures are needed to validate these findings.