Role of house-dust mites in childhood asthma.

The aetiological importance of the house-dust mite, Dermatophagoides sp., was examined in 133 asthmatic children referred to hospital. Evidence of sensitization to this allergen from positive skin tests and the presence of circulating specific IgE was found in the majority of these children and sensitization often began in the preschool years. In vitro studies of specific IgE levels were found to bear a close relation to nasal provocation tests and probably have an important place in the identification of offending allergens in the paediatric patient. Ecological studies of the house-dust mite revealed its common occurrence in domestic environments, especially in the bed and bedroom. The mites were not found in hospital beds and only low levels of infestation were found in perambulators and cots and in residential schools for `delicate' children. The findings stress the major importance of this allergen in the causation of childhood asthma.