Early allergen exposure and atopic eczema

Harris, J.M. and Williams, H.C. and White, C and Moffat, S and Mills, A.J. and Newman, Taylor and Cullinan, P (2007) Early allergen exposure and atopic eczema. British Journal of Dermatology, 156 . pp. 698-704.

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Abstract

Background The relationship between exposure to indoor aeroallergens in early life

and subsequent eczema is unclear. We have previously failed to show any significant

associations between early life exposure to house dust mite and cat fur

allergens and either sensitization to these allergens or wheeze. We have also previously

reported a lower prevalence of parent-reported, doctor-diagnosed eczema

by age 2 years for children exposed to higher concentrations of house dust mite,

but no other associations with other definitions of eczema or for exposure to cat

allergen.

Objectives To extend the exposure–response analysis of allergen exposure and

eczema outcomes measured up to age 8 years, and to investigate the role of

other genetic and environmental determinants.

Methods A total of 593 children (92Æ4% of those eligible) born to all newly pregnant

women attending one of three general practitioner surgeries in Ashford,

Kent, were followed from birth to age 8 years. Concentrations of house dust

mite and cat allergen were measured in dust samples collected from the home at

8 weeks after birth. The risk of subsequent eczema as defined by the U.K. diagnostic

criteria was determined according to different levels (quintiles) of allergen

exposure at birth.

Results By age 8 years, 150 (25Æ3%) children had met the diagnostic criteria for

eczema at least once. Visible flexural dermatitis was recorded at least once for

129 (28Æ0%). As in other studies, parental allergic history was positively associated

with most eczema outcomes, as were higher maternal education and less

crowded homes. No clear linear associations between early exposure to house

dust mite or cat allergen were found, regardless of the definition of eczema used.

The risk of eczema appeared to increase for the three lowest quintiles of house

dust mite allergen exposure (odds ratio, OR 1Æ37 for third quintile compared

with first), and then to fall for the two highest quintiles (OR 0Æ66 and 0Æ71)

even after controlling for confounding factors.

Conclusions The lack of any clear exposure–disease relationship between allergens

in early life and subsequent eczema argues against allergen exposure being a

major factor causing eczema. If the lower levels of eczema at higher levels of

house dust mite are confirmed, then interventions aimed at reducing house dust

mite in early infancy could paradoxically increase the risk of subsequent eczema.

Item Type: Article
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Medicine
Depositing User: attreed, karen
Date Deposited: 08 Apr 2008 12:40
Last Modified: 08 Apr 2008 12:40
URI: http://eprints.nottingham.ac.uk/id/eprint/857

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