Association between varicella zoster virus infection and atopic dermatitis in early and late childhood: A case-control study

Background: Wild-type varicella zoster virus infection (WTVZV) early in childhood has been shown to protect against the development of asthma and atopy. Objective: To determine whether WTVZV in childhood protects against atopic dermatitis (AD). Methods: This retrospective, practice-based, case-control study randomly sampled 256 children and adolescents (age 1-18 years) with AD and 422 age-matched healthy controls from 2005 to 2007. Observations were made before the a priori hypothesis. Results: (1) A single episode of WTVZV in childhood is associated with decreased odds ratio (OR) of developing AD (conditional logistic regression; OR, 0.55; 95% CI, 0.34-0.89; P = .01). (2) When using intervals for age corresponding to bimodal distribution of age of WTVZV infection, the effects of WTVZV infection are significant when occurring at age 0 to 8 years (OR, 0.56; 95% CI, 0.35-0.90; P = .02), but not at 8 to 18 years (OR, 0.50; 95% CI, 0.19-1.31; P = .16). Considering 5-year intervals has similar findings. (3) WTVZV is associated with decreased odds of moderate AD (multinomial logistic regression; OR, 0.08, 95% CI, 0.04-0.15; P < .0001) or severe AD (OR, 0.04; 95% CI, 0.01-0.13; P < .0001). (4) WTVZV in children is associated with prolonged AD-free survival (Kaplan-Meier; median, 15.3 years; 95% CI, 10.9-18.0) compared with controls (median, 7.5 years; 95% CI, 4.8-11.9; log-rank test, P < .0001). (5) Children with WTVZV, compared with vaccine, who eventually develop AD require fewer pediatrician sick visits for management of AD (logistic regression; OR, 0.17; 95% CI, 0.06-0.51; P = .001). Conclusion: WTVZV in childhood protects up to 10 years of age against AD, delays onset of AD symptoms, and decreases AD severity and office visits. (J Allergy Clin Immunol 2010;126: 300-5.)