Increasing severity of early-onset atopic dermatitis, but not late-onset, associates with development of aeroallergen sensitization and allergic rhinitis in childhood.

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 HanifinR GEE OR = 1.68 [1.08; 2.62], p = .02 and 1.08 [1.03; 1.12], p < .001, whereas late-onset AD showed a borderline significant association and late-onset severity showed no association; GEE OR = 1.65 [0.92; 2.94], p = .08 and 1.01 [0.97; 1.06], p = .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 = .04 and severity; GEE OR = 1.09 [1.05; 1.13], p < .001, whereas late-onset AD showed no association. The effects on sensitization and rhinitis of early-onset versus late-onset AD severity were significantly different: p-interactionsensitization  = .03 and p-interactionrhinitis  < .01. CONCLUSION Increasing severity of early-onset AD, but not late-onset AD, associates with aeroallergen sensitization and allergic rhinitis later in childhood.