Association Between Varicella Zoster Virus Infection and Atopic Dermatitis in Childhood: A Comparative Cross-Sectional Study

Background: The hygiene hypothesis suggests infections in childhood may protect against atopic dermatitis (AD). Objective: To determine the association between varicella zoster virus (VZV) infection/varicella virus vaccination (VV) in childhood and the severity of AD. Methods: The study was a comparative cross-sectional study. Demographic characteristics and clinical history of VZV and VV were collected. The severity of AD was calculated using the SCORing Atopic Dermatitis (SCORAD) severity scale. Serum varicella immunoglobulin G (IgG) titer was done. Statistical analysis was done. Results: 234 patients having AD with almost equal representation by males and females were recruited for the study. A history of VZV infection was present in 68 patients. None of the patients gave history of VV. Serum IgG titers were done in 78 patients. Mean age was found to be 7.23 ± 4.05. Patients having a history of VZV infection had mild severity of AD. The median total number of AD episodes and the median number of hospital visits each year, median SCORAD were lower, and the median age of onset of AD and the median IgG titer of study participants were higher among patients having a history of VZV infection. There was a statistically significant negative (inverse) correlation between SCORAD and IgG titer. Limitations: This is a site-limited study. There may be recall and selection bias while collecting data. SCORAD being not completely objective is another limitation. Estimation of immunoglobulin-E levels and characterization of lymphocyte-monocyte subset were not done. Conclusion: VZV infection in childhood prior to onset of AD is a protective factor for atopic dermatitis.