The effect of anti-allergic mattress encasings on house dust mite-induced early- and late-airway reactions in asthmatic patients. A double-blind, placebo-controlled study

Background Anti‐allergic mattress encasing may provide clinical benefit in asthmatic patients. However, the effect of mattress encasings on allergen‐specific parameters, such as bronchial reactions to house dust mite (HDM) challenge, is not clear. Objective To investigate the effect of anti‐allergic mattress encasings on allergen sensitivity in patients with moderate to severe asthma. Methods Twenty‐seven patients with asthma and HDM allergy were studied in a double‐blind, placebo‐controlled study. Concentrations of Dermatophagoides pteronyssinus (Der p 1) were measured in mattress dust before and after 1 year of treatment; bronchial histamine challenge, bronchial challenge with HDM and intradermal skin challenges with HDM were performed. The number of eosinophils in peripheral blood was assessed. Results In the active group, but not in the placebo group, there was a significant reduction in Der p 1 concentration in the dust collected from the mattresses after 1 year of treatment compared to before. There was a significant difference between the groups with respect to HDM‐induced early‐reaction (ER) in the airways and the number of blood eosinophils, which reflected an increase in ER and eosinophils in the placebo group without significant change in the active group. No significant improvement in PC20 histamine, late‐reaction (LR) and skin tests was found in either groups. Conclusion Our data suggest that encasings protect against a further increase in allergen sensitivity in asthmatic patients, so their use should be recommended.