Patterns of sensitization to food and aeroallergens in the first 3 years of life
Received 25 January 2007; received in revised form 28 June 2007; accepted 28 June 2007. published online 10 September 2007.
Background
There is a paucity of longitudinal studies of allergen sensitization in childhood.
Objective
To investigate the pattern of sensitization in early childhood.
Methods
A nested cohort of children (n = 543) were followed up from birth and given a skin prick test (SPT) at 1, 2, and 3 years of age. A detailed clinical history was obtained.
Results
The prevalences of sensitization to aeroallergens were 1.3%, 6.4%, and 10.7% at 1, 2, and 3 years of age. The figures for food allergens were 2.8%, 3.9%, and 3.7%. There was a statistically significant increase in the prevalence of sensitization to ≥1 allergen between years 1 and 2 (P < .001) and years 2 and 3 (P = .032). Among those with a positive SPT at 1 year, 29% tested positive to additional allergens at 2 years (P = .0054). Sensitization to milk or egg at 1 year was a predictor for increased sensitization to peanut at 3 years (odds ratio, 34.8; P < .0001). Sensitization to egg at 1 year was associated with increased sensitization to aeroallergens at 3 years (odds ratios, house dust mite, 27.1, P < .001; cat, 8.9, P < .01; grass, 11.8, P = .005). For peanut and cat allergens, wheal size increases with the age of the child (P = .009 and P = .017, respectively).
Conclusion
Sensitization to allergens as demonstrated by positive SPT tends to increase with age, and this change can be detected in the first 3 years of life.
Clinical implications
The high predictive value for early sensitization and a linear increase in SPT reactivity provide an opportunity for early intervention.
aDavid Hide Asthma and Allergy Research Center, St Mary's Hospital, Newport, Isle of Wight
bSchool of Health Sciences and Social Work, University of Portsmouth, Portsmouth, United Kingdom
Reprint requests: Taraneh Dean, PhD, School of Health Sciences and Social Work, University of Portsmouth, James Watson West, 2 King Richard 1st Road, Portsmouth, PO1 2FR, United Kingdom.
Supported by the Food Standards Agency, United Kingdom (grant #T07023).
Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.
ABSTRACT