Chickenpox in childhood is associated with decreased atopic disorders, IgE, allergic sensitization, and leukocyte subsets.

BACKGROUND: Wild-type varicella zoster infection (WTVZV) up to 8 yr of age has been shown to protect against atopic dermatitis (AD) and asthma. We sought to determine whether WTVZV in childhood protects against atopic disorders, allergic sensitization or decreases serum Immunoglobulin E (IgE) levels. METHODS: We conducted a retrospective, practice-based study of outpatient pediatric practices in NY. One hundred children with WTVZV up to 8 yr of age and 323 children who received varicella vaccine (VV) were randomly selected. RESULTS: WTVZV up to 8 yr of age is associated with decreased odds of subsequent asthma (exact logistic regression; OR = 0.12, 95% CI = 0.03-0.57, p = 0.003), allergic rhinoconjunctivitis (OR = 0.16, 95% CI = 0.05-0.49, p = 0.0003), and AD (OR = 0.57, 95% CI = 0.33-0.96, p = 0.02), but not food allergies (p = 0.78); decreased total serum IgE levels [mixed linear model, LSM (95% CI): 129.09 (33.22-501.63) vs. 334.21 (102.38-1091.04) IU/ml; p = 0.02] remained significant at all time intervals after WTVZV (<5, 5-10, and >10) compared with VV (p = 0.003-0.03). WTVZV was associated with decreased allergic sensitization (logistic regression, OR = 0.11, 95% CI = 0.03-0.38, p = 0.0004). WTVZV is also associated with persistently decreased numbers of peripheral blood lymphocytes (p < 0.0001) for up to 12 yr (p = 0.0003-0.047), monocytes (p = 0.002) for up to 16 yr (p < 0.001) and basophils at ages 4-6, 10-12, and 14-16 (p < 0.03). CONCLUSION: WTVZV up to 8 yr of age protects against atopic disorders, which is likely mediated by suppression of IgE production and allergic sensitization, as well as altered leukocyte distributions.

Association between obesity and atopic dermatitis in childhood: a case-control study.

BACKGROUND: Obesity in children is associated with increased asthma and atopy. OBJECTIVE: We sought to determine whether obesity in childhood or adolescence increases the risk of atopic dermatitis. METHODS: This retrospective, practice-based, case-control study randomly sampled 414 children and adolescents (age, 1-21 years) with atopic dermatitis between January 2000 and December 2007 and 828 randomly sampled healthy control subjects. Information was obtained from an electronic medical record. Observations were made before the a priori hypothesis. RESULTS: Obesity in children is associated with increased atopic dermatitis (conditional logistic regression: odds ratio, 2.00; 95% CI, 1.22-3.26; P = .006). These atopic dermatitis-predisposing effects are found when obesity started by less than 2 years of age (adjusted odds ratio [aOR], 15.10; 95% CI, 1.51-151.21; P = .02) and 2 to 5 years (aOR, 2.58; 95% CI, 1.24-5.41; P = .01) but not greater than 5 years (aOR, 1.32; 95% CI, 0.66-2.64; P = .43) and when obesity was prolonged for 2.5 to 5 years (aOR, 2.64; 95% CI, 1.13-6.18; P = .03) and greater than 5 years (aOR, 3.40; 95% CI, 1.34-8.63; P = 0.01). Obesity is associated with more severe atopic dermatitis (ordinal logistic regression: aOR, 2.37; 95% CI, 1.24-5.37; P = .01). Obese children who eventually have atopic dermatitis require more frequent pediatrician visits for the management of atopic dermatitis (ordinal logistic regression: aOR, 2.22; 95% CI, 1.12-4.50; P = .03). CONCLUSION: Prolonged obesity in early childhood is a risk factor for atopic dermatitis. Weight loss might be an important approach for the prevention and treatment of atopic dermatitis in children.

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.