Early allergen exposure and atopic eczema

Harris, J.M.; Williams, H.C.; White, C; Moffat, S; Mills, A.J.; Newman, Taylor; Cullinan, P

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.

Citation

Harris, J., Williams, H., White, C., Moffat, S., Mills, A., Newman, T., & Cullinan, P. (2007). Early allergen exposure and atopic eczema. British Journal of Dermatology, 156,

• Journal Article Type: Article
• Publication Date: Jan 1, 2007
• Deposit Date: Apr 8, 2008
• Publicly Available Date: Apr 8, 2008
• Journal: British Journal of Dermatology
• Print ISSN: 0007-0963
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• Volume: 156
• Public URL: https://nottingham-repository.worktribe.com/output/1017449