Early-onset eczema is associated with increased milk sensitization and risk of rhinitis and asthma in early childhood

Atopic eczema and food allergy most commonly occur in the early childhood. However, the relationships between eczema onset and their relevance to the occurrence of atopic diseases relating to allergen sensitization remain unclear. We investigated 186 children who were followed up regularly at the clinic for 4 years in a birth cohort study. The children were classified into three groups: early-onset eczema (<2 years old, n = 55), late-onset eczema (≥2 years old, n = 40), and never eczema groups (n = 91). The associations between the different onsets of eczema and total immunoglobulin E levels, absolute eosinophil count, sensitization to food and inhalant allergens, and allergic outcomes were assessed. A significantly higher prevalence of sensitization to food, especially milk was observed in children with early-onset eczema compared with those without eczema at age 1, 1.5, 2, 3, and 4 years. Furthermore, a significantly higher number of eosinophils was detected in children with early or late-onset eczema at the age of 1.5 years. Both the early- and late-onset eczema were significantly associated with a higher prevalence of allergic rhinitis at age 2, 3, and 4 years, and asthma at age 2. Moreover, the early-onset eczema group showed a significantly increased risk of allergic rhinitis (P = 0.010) and asthma (P = 0.032) at age 4. The children with early-onset eczema (<2 years old) appear to be associated with an increased prevalence of milk sensitization and risk of rhinitis and asthma in early childhood.