Hen's egg, not cow's milk, sensitization in infancy is associated with asthma

To the Editor:
Children of parents with allergies are at an increased risk of developing asthma. Early insight into the prognosis of these highrisk children is important for parents as well as for clinicians. Allergic sensitization is often used to predict asthma. Previously, in the German Multicenter Allergy Study, children sensitized to hen’s egg at age 1 year were at an increased risk of allergic sensitization at the age of 3 years. Egg sensitization was previously associated with asthma in prospective studies. In a Dutch cohort of children with more repeated measurements and additional outcome measures, our study aimed to investigate whether sensitization to hen’s egg allergen at age 1 year is more strongly associated with asthma development than is sensitization to other allergens.
The study population consisted of 565 children of mothers with allergies who participated in a birth cohort study and, around their first birthday, provided a serum sample for the determination of IgE level. Their mothers (reporting at least 1 of the following: asthma ever, pet allergy, house dust mite [HDM] allergy, or nasal allergy) were included during pregnancy in the Intervention study (total n 5 855) of the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort.6 The PIAMA intervention consisted of mite-impermeable mattress covers on the parents’ and child’s bed.
At age 1 year, specific IgE level to cow’s milk, hen’s egg, HDM, cat, and dog was measured and sensitization was defined as a specific IgE level of 0.35 IU/mL or more. Atopy was defined as sensitization to any of these allergens.
[...]