Efficacy of the acaricide: acardust for the prevention of asthma and rhinitis due to dust mite allergy, in children.

A double blind, randomized, comparative study versus placebo, was done during 6 months in 32 children, aged 4-12 years, who suffer from either allergic asthma or rhinitis or both, slept in a bedroom rich in dust mite, have well documented allergy solely to house dust mite (H.D.M.), and a condition severe enough to require continuous medication. After thorough cleaning, their bedrooms were sprayed on day 0 and day 90 with the total content of a canister containing either Acardust or Placebo. Rooms were cleaned regularly throughout the study period. Each child completed an individual daily score card (scales from 0-3) for asthma, and rhinitis symptoms, medication taken, and any additional symptoms. Peak flow was recorded twice weekly. All the children were examined every month (at the clinic) when also PFF, FEVI, doctor's and patient's opinion of clinical symptoms were recorded according to the same scale (0-3) and dust samples from child's bedroom were examined for H.D.M. antigen content. At day 0, 90 and 180, total IgE and dust mite specific IgE determination was done. At the end of the study, patient's and doctor's opinion about the spray's efficacy were recorded on a scale from 0-3. The results were in favor of Acardust for asthma, according to patient's opinion (p = 0.001), doctor's opinion (p = 0.04) and individual score cards (p = 0.03), and for nasal secretion (p = 0.01), sneezing and lacrimation (p = 0.02); concurrent medication dropped significantly (p = 0.01) in the Acardust group. No side-effects were reported. We consider Acardust a safe and valuable preventive treatment in H.D.M. allergy.

Can mite-specific IgE be used as a surrogate for mite exposure?

Several epidemiologic studies suggest that in mite-sensitive patients symptoms are dependent upon mite-exposure level. However, in clinical practice, it si not easy to measure major mite allergens. In contrast, assay of specific IgE antibodies can be done routinely. Thus, we wanted to compare, in a group of 40 mite-sensitive patients, the levels of mite-specific IgE (measured by RAST grade 0-6) and the level of mite group I allergen in mattresses (measured in micrograms/g house dust). The correlation coefficient between both variables was highly significant (P = 0.001). Subjects with a RAST grade of 3 or more had a 77% probability of being exposed to high (i.e., > 10 micrograms/g dust) mite allergen level. In contrast, subjects with RAST grades 0, 1, or 2 had a 77% probability of not being exposed to such high levels. Thus, measurement of serum mite-specific IgE level could be used in routine prediction of mite exposure.