Nasal allergen challenge tests - methods of clinical application

The nasal provocation test (NPT) is a standardized method for the detecting the clinical relevance of allergic rhinitis. It's a method of high specificity and sensitivity. The NPT helps identifying a type I sensitization in cases of unclear or contradictory previous diagnostic results and furthermore it appears to be a good tool in monitoring the clinical effect of specific immunotherapy in clinical trials, as well as detecting a possible aspirine-intolerance-syndrome (Samter's syndrome). The NPT is a very simple, reasonable and safe method on the one hand, but on the other the performance is quite time consuming. A single test takes approximately 45 minutes and a complete titration up to 3 hours. Subjective and semiquantitative methods like secretion, irritation and remote symptoms documented in semiquantitative scores as well as well-established objective methods of measurement such as anterior rhinomanometry, acoustical and optical rhinometry and others are used to evaluate the NPT. In German speaking countries the NPT is standardized by a guideline, only a few aspect such as the adequate dose and technique remain subject of scientific debate.