Randomized Trial to Prevent Sensitization to Mite Allergens in Toddlers and Preschoolers by Allergen Reduction and Education: One-year Results

Objective: To evaluate the effectiveness of prevention measures against dust mite sensitization.

Design: European (England, Germany, Greece, Lithuania) multicenter prospective single-blind randomized control trial with a follow-up of 12 months.

Participants: Toddlers and preschoolers, with at least 1 parent with atopic symptoms and sensitization, who initially were not sensitized to mite allergens.

Interventions: A combination of education and a simple preventive measure (mattress encasement) to reduce mite allergen exposure.

Setting: Community-based study.

Main Outcome Measures: Sensitization to mite allergens (skin-prick test or specific immunoglobulin E).

Results: Of 636 children (mean age, 3.1 years) included in the study, 566 (89%) participated in the first-year follow-up. The incidence of sensitization to mite allergens was 10 (3%) of 330 in the intervention vs 20 (6.5%) of 306 in the control arm, including loss of follow-up (intention-to-treat principle). Allergic symptoms were more common in sensitized than in nonsensitized children and so was the prevalence of physician-diagnosed asthma, eczema, and food allergy.

Conclusions: This simple, harmless, and inexpensive measure can be used in toddlers and preschoolers of parents with atopic disorders to reduce sensitization to mite allergens. With regard to clinical manifestations of atopy, follow-up studies are needed to determine the effectiveness of the intervention.