A double-blind, placebo controlled trial of solidified benzyl benzoate applied in dwellings of asthmatic patients sensitive to mites: clinical efficacy and effect on mite allergens.
BACKGROUND
The aim of this double-blind, randomized study was to investigate the effectiveness of an acaricidal cleaning product in modifying both clinical symptoms and mite allergen levels over a period of at least 1 year.


METHODS
Twenty-six asthmatic patients with proven Dermatophagoides pteronyssinus (Dp) asthma were selected; three were withdrawn from the trial. The patients' homes were divided into two groups; 11 homes were treated with solidified benzyl benzoate and tenside agents (A), and 12 were treated with a placebo (P). Two applications were performed at the beginning of the trial and at least 6 months later. Patients were examined 1 month before the trial, at the beginning of the trial, and every 3 months over a period of 1 year. Indoor mite exposure was evaluated by three methods: semiquantitative guanine determinations, quantitative guanine determinations, and the measurement of Der p I + Der f 1 (antigen P, of Dp + antigen F1 of D. farinae) levels.


RESULTS
The symptom scores established at the beginning of the trial and 12 months later showed a statistically significant improvement only in the A group (p < 0.01). The visual analog scale also showed a statistically significant difference both in the A (p < 0.05) and P groups (p < 0.01). No statistical differences were found between medication scores in the A or P groups. A statistically significant increase was also observed for forced expiratory volume in 1 second and maximal expiratory flow rate 25/75 in the two groups (p < 0.05 for P group; p < 0.01 for A group). The mean decreases in Der p I + Der f 1 in patient mattresses between the beginning of the trial and after 12 months were 20% for the acaricide group and 17% for the placebo group, respectively (NS). For house dust samples with origins other than the patients' mattresses we found significant decreases in Der p I+Der f 1 in the A group (p < 0.01 for carpets and p < 0.05 for upholstery elements).
Dietemann
A
A
Service de Pneumologie, Hôpital Civil, Hopitaux Universitaires de Strasbourg, France.
Bessot
J C
JC
Hoyet
C
C
Ott
M
M
Verot
A
A
Pauli
G
G
D000293:Adolescent; D000328:Adult; D016902:Air Pollution, Indoor / Q000517:prevention & control; D000485:Allergens / Q000276:immunology*; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000276:immunology / Q000517:prevention & control*; D001565:Benzoates; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007306:Insecticides; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology*; D010919:Placebos; D013983:Tick Control
D000485:Allergens; D039741:Antigens, Dermatophagoides; D001565:Benzoates; D007306:Insecticides; D010919:Placebos; C006723:benzyl benzoate