ABSTRACT
Background: Early exposure to allergens through a defect skin
barrier has been proposed as a mechanism for inducing sensitization and
development of allergic diseases. We hypothesized that early-onset,
severe atopic dermatitis (AD) is associated with development of
aeroallergen sensitization and allergic rhinitis.
Methods : We included 368 children from the Copenhagen
Prospective Studies on Asthma in Childhood2000(COPSAC2000) at-risk mother-child cohort. AD was
diagnosed prospectively based on Hanifin&Rajka’s criteria and severity
assessed using the Scoring Atopic Dermatitis (SCORAD) index. Early-onset
AD was defined as debut ≤1 year, late-onset as debut from 1-6 years.
Aeroallergen sensitization and allergic rhinitis were diagnosed at ages
6-7 and 12 years. Associations between early-onset and late-onset AD and
allergy endpoints were calculated using general estimating equations
(GEE) models to compute the overall odds ratios (OR) for both time
points.
Results : Early-onset AD (yes/no) and severity (SCORAD) were
associated with development of aeroallergen sensitization during
childhood; GEE OR=1.68 [1.08; 2.62], p=0.02 and 1.08 [1.03;
1.12], p<0.001, whereas late-onset was not; GEE OR=1.65
[0.92; 2.94], p=0.08 and 1.01 [0.97; 1.06], p=0.55. The same
trend was seen for allergic rhinitis with significant association
between early-onset AD and allergic rhinitis; GEE OR=1.56 [1.01;
2.41], p=0.04 and severity; GEE OR=1.09 [1.05; 1.13],
p<0.001, whereas late-onset AD showed no association. The
effects on sensitization and rhinitis of early-onset vs. late-onset AD
severity were significantly different:
p-interactionsensitization=0.03 and
p-interactionrhinitis<0.01.
Conclusion : Increasing severity of early-onset AD, but not
late-onset AD, associates with aeroallergen sensitization and allergic
rhinitis later in childhood.
Keywords: Atopic dermatitis; early-onset; late-onset; severity; SCORAD;
Filaggrin mutation; aeroallergen sensitization; specific IgE; allergic
rhinitis; childhoodAbbreviationsAD = Atopic Dermatitis
COPSAC = Copenhagen Prospective Studies on Asthma in Childhood
SCORAD = Scoring Atopic Dermatitis
FLG = Filaggrin
OR = Odds Ratio
GEE = General Estimating Equations
sIgE = specific IgE