PURPOSE OF THE STUDY.
To describe the natural history of allergen sensitization in a cohort of infants with early-onset atopic dermatitis (AD) and to identify biomarkers predictive of development of sensitization to inhaled allergens.
This study included patients from the Observatory of Respiratory risks linked with Cutaneous Atopy (ORCA) study, a 10-year, longitudinal, prospective study of children with AD referred by their primary care physician to a tertiary care center in Paris, France.
Children included were younger than 12 months with active AD diagnosed by a dermatologist according to established criteria. Children with a history of wheezing were excluded. At baseline, AD severity was assessed by SCORAD (Scoring Atopic Dermatitis) questionnaire. Parents were asked about history of food allergies. Total and specific immunoglobulin E to inhaled (house dust mite [HDM], cat, dog, pollens [birch tree, timothy grass, mugwort], cockroach) and food (cow’s milk, hen’s egg, peanut, soy, fish, wheat) allergens as well as blood eosinophil counts were measured at study inclusion and then annually until age 6 years.
There were 229 patients included in baseline characteristics analysis, and 190 completed the study final visit. Participants were 58.5% male with mean age of 6.5 (± 2.7) months and mean SCORAD of 34.2 (± 21.0). Six percent of the subjects had a history of food allergy. At study inclusion, 58% were sensitized to food allergens, predominantly cow’s milk, hen’s egg, and peanut. Seventeen percent of subjects were sensitized to inhaled allergens, mostly cat (52%), HDM and dog (17%), and pollens (12%). By the end of the study period, sensitization to foods decreased to 34% of participants, whereas sensitization to inhaled allergens increased to 67% of participants, predominantly timothy grass pollen (30%), HDM (28%), and birch pollen (18%). Blood eosinophilia, AD severity, and history of food allergy were not associated with increased risk for developing inhaled allergen sensitization. Sensitization to food allergens at study inclusion, particularly multiple food sensitizations, was associated with the highest risk of developing inhaled allergen sensitization (odds ratio 4.32, 95% confidence interval 2.22–8.40; P < .001).
The authors concluded that in a specific population of children with early-onset AD, sensitization to food allergens was associated with increased risk of developing sensitization to inhaled allergens, with multiple food sensitizations conveying the highest risk.
This study prospectively examined a group of highly selected infants with early-onset AD and provided valuable information about the natural history of allergen sensitization in these patients. Distinct phenotypes of allergic disease are beginning to be identified because of studies such as this one. It is hoped that this information will allow us to predict a patient’s risk of development of other allergic conditions such as asthma and will facilitate earlier intervention with appropriate medical treatment.
- Copyright © 2015 by the American Academy of Pediatrics