Thursday, July 17, 2003
Two studies found that mite-proof bed coverings, at least by themselves, fail to relieve asthma and allergies, a perplexing discovery that challenges the frequent advice of doctors. Doctors and medical groups widely recommend dust mite-proof bed coverings to treat allergies and the asthma they can cause.
Up to 50 million Americans have allergies. Studies suggest that 40 percent to 60 percent of allergy sufferers in some areas are sensitive to dust mites, near-microscopic creatures that live in house dust and lay eggs in bedding. The tightly woven coverings hold in their irritating allergens and keep new mites from bedding.
The findings of the two European studies were reported in today's New England Journal of Medicine.
Though small previous studies reached mixed conclusions on the value of bed coverings, there is strong evidence that blocking allergens relieves symptoms. For example, asthmatics improve at clinics or hospitals with fewer mites.
Yet, in a seeming paradox, the yearlong European studies found no difference in symptoms between people with and without bed coverings. The English study was the largest of its kind, with 1,122 asthma patients. The Dutch study looked at 232 patients with hay feverlike allergies
New England Journal of Medicine, Volume 349:225-236, July 17, 2003
Control of Exposure to Mite Allergen and Allergen-Impermeable Bed Covers for Adults with Asthma
Ashley Woodcock, M.D., et. al.
New England Journal of Medicine, Volume 349:237-246, July 17, 2003
Evaluation of Impermeable Covers for Bedding in Patients with Allergic Rhinitis
Ingrid Terreehorst, M.D., et. al.