Natural history of sensitizations in atopic dermatitis. A 3-year follow-up in 250 children: food allergy and high risk of respiratory symptoms.

BACKGROUND AND
DESIGN: The aim of the study was to define the natural history of sensitization in atopic dermatitis (AD) through cross-sectional (comparison of three age classes) and longitudinal study: 250 children with minor (32.5%), moderate (32.5%), and severe (35%) AD were examined for aeroallergen and food hypersensitivity (skin tests, clinical scoring after allergen elimination, and food challenges).
RESULTS: The allergic screening was negative in minor AD and positive in 33% of cases of moderate AD that were concerned with aeroallergen sensitizations with only limited respiratory involvement. This suggests that nonspecific cutaneous hyperreactivity remains an almost exclusive precipitating factor in moderate or minor AD. Severe AD was characterized by a positive allergologic assessment in 100% of patients: food allergens were incriminated as flare factors in 96% of patients, with associated aeroallergen sensitization in 36%. Even at a young age (less than or equal to 2 years), the severe AD group is marked by an extreme frequency of food sensitization (93%) that persists in 73% of children younger than 7 years and 67% younger than 16 years. From the comparison of three age classes, the sequence of food and respiratory sensitization seems to be part of the natural course of AD. Prospective study in 29 children of group 1 (less than 2 years) with a 3-year follow-up confirms the data of the cross-sectional study since 27 had development of aeroallergen sensitization, with respiratory symptoms as early as age 3 years in 23 of these children.
CONCLUSION: The detection of food allergy in a child presenting with AD is likely to indicate a prognosis of severe AD and should be considered by dermatologists as a potentially important predictor of further respiratory symptoms.