Background: A recent study hypothesized that a skin-mediated immune response leads to atopic sensitization. However, prospective studies investigating sensitization during infancy are limited.
Methods: This cohort study included unselected infants born at NTT Medical Center Tokyo between March 2008 and February 2009. At age 3, 6, 9, and 12 months, they underwent physical examinations and a skin prick test (SPT). Associations of predictor variables with sensitization, atopic dermatitis (AD), and food allergy (FA) at ≤1 year were analyzed.
Results: Of 317 infants, the SPT was positive in 25 (8%) at 3 months and 133 (42%) at least once. Of the SPT-positive infants at 3 months, 19 (76%) had atopic diseases at ≤1 year (OR, 13.9; 95% 95%CI, 5.3-36.6). The presence of dermatitis at ≤3 months was significantly associated with sensitization (aOR, 3.0; 95%CI, 1.8-5.0), AD (aOR, 13.0; 95%CI, 4.5-37.3), and FA (aOR, 28.4; 95%CI, 3.3-240.6) by the age of 1 year. Point prevalence of sensitization paralleled the incidence of dermatitis. Almost all FA infants had experienced dermatitis at ≤3 months. In infants with dermatitis at ≤3 months, breast-feeding was significantly associated with sensitization (OR, 2.5; p=0.005) and FA (OR, 3.0; p=0.004). Infants without eczema at ≤3 months rarely developed AD or FA.
Conclusions: The presence of dermatitis in the first few months after birth is a strong risk factor for atopic sensitization and FA during the first year of life.