RESUMO
BACKGROUND: Cockroach allergens sensitized patients at a very young age and can predispose to severe asthma on atopic children. OBJECTIVE: To evaluate the FEV, changes induced after bronchoprovocation with Blatella germanica (Bg) or placebo on allergic respiratory children. MATERIAL AND METHODS: A prospective transversal study was performed in 25 children from 8 to 16 yr with allergic rhinitis and/or asthma diagnosis with sensibility only to Bg (Bayer Corp allergens) by Prick skin test, with a 1:20 weight/volume dilution. After previous training on spirometry, they assisted for a double blind bronchial challenge with 10, 25, 50, 75, 100, 150, 200, 300, 400, 500 until 750 proteic nitrogen units of Bg or 0.9% NaCl solution in a nebulized open circuit, with a 5 litter flow for 3 min. A week after, they returned for the crossover double blind bronchial challenge. At the beginning of the study a basal spirometry was performed and subsequent spirometrics at 1.5 and 3 min after each challenge with a 10 min rest between the challenges. The test was interrupted if cough, dyspnea, wheezing and/or a 15% or more FEV1 fall appeared. RESULTS: Twelve patients showed a FEV1 fall with the antigen challenge, all with specific lgE for Bg. All they had positive skin test to Bg, 9 had asthma and rhinitis and 3 only asthma. When placebo was used 6 patients showed a FEV1 fall. When comparing the average basal and final FEV1 values after the challenges, the fall was statistical significant in both groups with a p = 0.0015 when Bg was used, and p = 0.046 with placebo. CONCLUSION: These results show that two times fold number of patients challenged with Bg had a FEV1 fall than placebo, and the t Student test showed that antigen challenge was more significant than placebo. We demonstrated that respiratory allergic patients sensitised with Bg after a bronchial challenge with these allergens show a FEV1 fall. This suggests that cockroach allergen sensitisation can be on account of children's asthma.