Spinhaler specific bronchoprovocation challenges: short interval administration of micronized freeze-dried allergen...

Two different methods of antigen bronchial challenge, with micronized freeze-dried extract of D. pteronyssinus administered as a powder by a spinhaler, were evaluated in 15 asthmatic children, who were skin test positive and RAST positive for house dust mite D. pteronyssinus. In one method, daily increasing dose method (DIDM), a single antigen challenge was performed every day successively. In the other method, cumulative dose method (CDM), the antigen doses were administered successively with 7-minute intervals. The tests were considered positive when there was a fall of FEV1 greater than or equal to 20% of the baseline value. The DIDM showed a greater incidence of isolated late bronchoconstrictions. The CDM revealed a great incidence of biphasic reactions (early and late) and of laryngeal spasm. Two patients showed discordant results (positive with one method and negative with the other) suggesting problems related to intrasubject reproducibility.