Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms.

Background: Allergen exposure in early childhood is thought to be important for sensitization and subsequent development of asthma. Not much is known, however, about exposure of young children to allergens in the home.
Objectives: This study was designed to document dust mite allergen exposure in young children, and to determine whether infants from atopic mothers (= 'high-risk' infants) are exposed to lower concentrations of house dust mite allergen than infants from non-atopic parents (= 'low-risk' infants).
Methods: Dust samples were taken in the homes of 104 infants (48 'high-risk' and 56 'low-risk' infants, selected by questionnaire) aged 3-15 months, from floors in different rooms and from the child's mattress surface.
Results: The majority of the infants were found to be exposed to Der p I concentrations of more than 2000 ng/g in dust collected from the surface of their mattresses. Lower Der p I concentrations were found in mattress surface dust from the beds of infants from atopic mothers than of infants from non-atopic parents. Also, lower Der p I concentrations were found in floor dust from the homes of infants from atopic mothers. Infant beds equipped with new mattresses, new blankets and top plastic sheeting had significantly lower Der p I concentrations than beds equipped with used mattresses and blankets, without top plastic sheeting.
Conclusions: Young children in the Netherlands are exposed to significant concentrations of Der p I in mattress surface dust. Allergic parents appear to provide their children with environments somewhat less rich in mite allergen than non-allergic parents.