Optical rhinometry: application on children and adolescents for nasal provocation tests.

Optical rhinometry is a new method that allows the direct, real time measurement of changes in swelling of the nasal mucosa by external measurement. The measurement is carried out with monochromatic near-infrared light. The change of intensity of the swelling is displayed and recorded. Different preceding studies on adults already showed the reliability and absence of side effects of the measuring method. With the help of a prototype of an optical rhinometer specially developed for children, 65 measurements were performed on a total of 13 children and adolescents having one-sided nasal provocation tests with histamine and allergens, negative provocation tests with control solution and decongestion with xylometazoline. The nasal provocation tests were implemented by optical rhinometry while simultaneously using the established method of active anterior rhinomanometry. We found significant differences between positive and negative provocation tests in both methods (p < 0.01). Decongestion was different from all other groups in both methods (p < 0.01). No clear connection could be made between the percentage increase of rhinometric extinction and the percentage increase of obstruction measured by anterior rhinomanometry. The evaluation of the nasal provocation test via continuous direct measurement of swelling of the nasal mucosa membrane seems feasible in children. Data which so far could not be measured, such as the beginning of swelling and the time of the maximum state of swelling, might increase the diagnostic validity of provocation tests.