Abstract

Fiftyfour allergic patients with bronchial asthma or obstructive lung disease were investigated at admission and discharge after a 3 months hospitalization period in the alpine valley Davos. An intracutaneous skin test procedure was carried out with 16 common inhalant allergens. Histamine 0.01 mg/ml was used as a positive control and a phosphate buffered saline with 0.03% HSA and 0.5% phenol were used as negative controls. A liophylized control for house dust mite was used for every patient on admission and discharge, in order to control loss of allergen potency of the vial. Furthermore, an additional freshly prepared vial of house dust mite allergen was analyzed after it was opened and stored at 4°C after 3 months. The wheal and flare reactions were calculated separately for the early reaction (at 15 minutes) and the late reaction (at 6 hours). The sum of wheal/histamine index and fare/histamine index were calculated for the early phase reactions and analyzed according two-tailed paired student's t tests. Using RAST inhibition, the liophylized house dust mite showed the same allergen concentration as in the fluid form. The 3 months old vial was analyzed and showed the same allergen concentration as was expected. Results for histamine reactions on admission and discharge showed no significant difference. Patients showed no reactions on the negative controls. Differences were found between skin test reactions on admission and discharge for the sum of early wheal reactions (p = 0.0001), and to certain allergen wheal such as house dust mite and some other common allergens. We conclude that during a 12 weeks stay in the alpine climate Davos, intracutaneous early wheal reactions to certain allergens are decreasing possibly reflecting a decreased exposure. The late reaction showed no significant change.