Summary 

Backround: 
Bronchial allergen provocation (BAP) is an established tool for the diagnosis of allergy in patients with asthma. However, BAP cannot be used in multi center trials due to possible side effects and lack of experienced investigators. Nasal allergen provocation is an alternative method which is found to be safe without the need of specialized equipment. The aim of this prospective study was to evaluate the concordance of both methods in children and adolescents with suspected house dust mite (HDM) allergy. 

Methods: 
157 patients with allergic asthma and positive prick test for HDM were screened and 112 patients underwent BAP with the following parameters being analyzed: PD20FEV1 allergen, exhaled NO, total-IgE, and specific-IgE to HDM. Within 12 weeks, NAP with HDM was performed in 74 of 112 patients. Results were evaluated using the Lebel score as well as using PNIF to analyze nasal obstructions. Finally, a standardized questionnaire concerning life quality in patients with rhinoconjunctivitis was analyzed.

Results: 
57 of 74 patients had an early asthmatic reaction (EAR) by BAP, of these 41 were identified by using the Lebel score and 19 by using PNIF. While the score reached a sensitivity of 71,9% and a positive predictive value (PPV) of 89,1%, the sensitivity of PNIF was insufficient (33,3%) by reaching a PPV of 82,6%. Negative predictive values were 42,8% respectively 25,4%. In addition, an eNO grater or eval 10 ppb (AUC 0.78) and a specific-IgE to HDM greater or eval 25.5 kU/l (AUC 0,72)  predicted an EAR; a correlation to Lebel score could not be determined.





Conclusion:
Our results identified the Lebel score as the best predictor for an EAR. In contrast to the PPV, low NPV could not exclude an asthmatic reaction sufficiently. For PNIF we found no adequate test validity. In relation to pediatric patients, individual capabilities have a significant impact on measures. Nasal and bronchial mucosa show differences; so according to our findings BAP cannot be substituted by NPT in patients with asthma and suspected HDM allergy. However, especially in an ambulatory setting, NPT becomes significant due to low test requirements and a high level of patient safety. In addition, specific IgE as well as eNO could be identified as valid predictors for an EAR.