Nasal allergen provocation test: updated indications and diagnostic accuracy

The Nasal Allergen Provocation Test (NAPT) is a valuable diagnostic tool for allergic rhinitis, particularly in cases where conventional tests, such as the skin prick test (SPT) and serum-specific IgE (sIgE), yield inconclusive results. By replicating real-life allergen exposure in a controlled setting, NAPT enables the assessment of allergen-specific nasal reactivity. This article aims to review the current knowledge of NAPT. Recent studies have reinforced NAPT as the gold standard for confirming nasal allergic responses. In the past, test protocols, allergen dosages, and outcome measurements varied widely. However, advancements in allergen standardization, the combination of objective and subjective measurements, and metered nasal allergen application have led to an improved and more reliable test method, with ongoing efforts to establish a universal protocol for clinical testing. This review summarizes current knowledge on NAPT, including its clinical applications, indications, methodology, and recent advancements. Additionally, we compare NAPT with SPT and sIgE in terms of diagnostic accuracy. The protocols, allergen types and doses, test methodologies, and outcome measures of these studies were analyzed and compared.