Benefits unproved but not yet excluded

Papers p 1105

Since faecal pellets of house dust mites were identified as the principal source of allergen in house dust over 30 years ago,1 the role of mite eradication or allergen avoidance in the management of asthmatic patients has remained controversial.2

Enthusiasts point to studies in which allergic asthmatic patients stayed for several months in hospitals or high altitude Alpine sanatoriums. In these effectively mite free environments their condition improved both symptomatically and in terms of non-specific bronchial responsiveness. 34 These were, however, uncontrolled studies in which patient blindness was impossible, so not all the benefits can be attributed unequivocally to allergen avoidance. Nevertheless, that is the most plausible explanation, implying that radical reduction in mite allergen exposure may be beneficial to at least some asthmatics.

Sceptics emphasise the practical challenge of achieving sustained and substantial reductions in mite allergen exposure in the home, particularly in regions, including Britain, where mite infestation is widespread. In theory, personal exposure may be reduced by eradicating mites from the environment or …