Timing of atopic dermatitis onset influences variation in allergic march
The variation in the atopic march (asthma and seasonal allergies) may be partly explained by the timing of atopic dermatitis onset, suggests a recent study.
Researchers conducted a cohort study to examine the impact of the age of atopic dermatitis onset on the risk for asthma and seasonal allergies. They used the Pediatric Eczema Elective Registry, which is an observational cohort of patients with paediatric-onset atopic dermatitis.
Of the 3,966 children included in the study, 73 percent reported atopic dermatitis onset before the age 2 years. Patients with atopic dermatitis onset at ages 3 to 7 or 8 to 17 years had significantly lower rates of seasonal allergies and asthma compared with those whose onset occurred before age 2 years.
During follow-up, the adjusted relative risks for incident seasonal allergies were 0.82 (95 percent CI, 0.72 to 0.91) in the 3- to 7-years-old at onset group and 0.64 (0.47 to 0.83) in the 8- to 17-years-old at onset group compared with the age ≤2 years at onset group.
There was no significant difference in the adjusted risk for incident asthma between the older onset groups and the earliest onset group.
“These findings may improve future risk stratification of patients for treatment,” researchers said.
The results of this study also supported those of Gustafsson and colleagues, who found good prognosis and an increased risk of developing asthma and allergic rhinitis in children with atopic dermatitis. In addition, they concluded that development of other allergic symptoms correlated with a family history of eczema, age at onset of eczema and its severity, early adverse reactions to foods, and proneness to infections. [Allergy 2000;55:240-5]
The current study is limited by the use of self-reported onset age data, which may have resulted in misclassification bias.