Effective allergen avoidance for reducing exposure to house dust mite allergens and improving disease management in adult atopic asthmatics

Abstract

Objective: We investigated the best strategy for adult asthmatics to avoid exposure to Dermatophagoides group (Der-1) allergens. Methods: Adult atopic asthmatics (n = 111) followed a 32-item checklist for avoiding Der-1 allergen exposure. Twenty-five patients were excluded through incomplete sampling; 50 remaining patients encased their pillows/futons/mattresses in microfine-fiber covers, 13 used vacuum cleaners with dust-mite-collection nozzles, and 23 acted as non-intervention controls. During August–October 2010 and August–October 2011, dust samples were collected in Petri dishes placed in bedrooms for 2 weeks and from mattresses/futons by using adhesive tape on one morning. A Der-1 level decrease was defined as a mean 2011 Der-1 level of <1 as a ratio of the 2010 level on tape or Petri dish samples. We analyzed the associations between Der-1 level change (by ELISA) and % weekly variability in peak expiratory flow (PEF) or fraction of exhaled nitric oxide (FeNO) after intervention. Results: Der-1 levels decreased significantly in the covers group but not the vacuuming group. FeNO levels and PEF variability were unchanged in both groups. In patients whose Petri dish or tape samples showed decreased Der-1 levels, the % PEF variability was lower in 2011 than in 2010, but FeNO levels were unchanged. Three interventions (vacuuming all family members' mattress/futon surfaces at least weekly or after exposure of the futons to sunlight, and floor wiping before vacuuming), plus using covers, were the most effective management strategy in reducing Der-1 levels. Conclusions: This environmental and bedding maintenance program may help manage adult atopic asthma.

Keywords:

• Allergen avoidance
• atopic asthma
• Dermatophagoides
• group 1 mite antigen
• adult asthma
• asthma management

Acknowledgements

We thank Ms. Yumiko Takeuchi and Ms. Masayo Morie for performing the FeNO measurements.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article. NT examined the patients, analyzed data and statistics, was the main contributor to manuscript preparation, and was involved in manuscript preparation and editing. CO examined the patients and contributed to discussions about the patients. AS assayed the levels of Der 1 in tapes from futon or mattress covers and in the Petri dishes in the bedrooms. HY and KA contributed to discussions about the manuscript.

Funding

This study was supported by Health and Labor Science Research Grants for Research on Allergic Disease and Immunology, awarded by the Ministry of Health, Labor, and Welfare of Japan.