The Importance of Nasal Provocation Testing in the Diagnosis of Dermatophagoides pteronyssinus-Induced Allergic Rhinitis

Background Allergen identification is the first step for allergen-specific immunotherapy (AIT) of allergic rhinitis (AR). Currently, the diagnosis of AR is based mainly on the positive results of the skin prick test (SPT) and/or serum specific immunoglobulin E (sIgE) measurement. However, the results of these two tests may not always directly correlate with AR. Objective To investigate the importance of nasal provocation testing (NPT) in the diagnosis of Dermatophagoides pteronyssinus (Der p)-induced AR. Methods Rhinitis patients willing to undergo AIT (n = 171) were enrolled. The correlations of Der p SPT, sIgE, NPT, and clinical symptom severity were assessed. Results NPT-positive responses were more common in patients with higher SPT and sIgE levels. The optimal cut-off value for a NPT-positive response for SPT was 5.5 mm and for sIgE was 2.77 kUA/L, based on the respective receiver operating characteristic (ROC) curves. The area under the curve (AUC) of the ROCs was 0.814 (SPT only) and 0.794 (sIgE only) and increased to 0.828 with the combination of SPT and sIgE. The Der p-NPT concentration was inversely correlated with SPT and sIgE levels ( r = −0.477, P < .001, and r = −0.461, P < .001, respectively), but none was correlated with the total nasal symptom score. Conclusion For patients who are willing to receive Der p AIT, NPT is a useful and safe test to confirm diagnosis prior to treatment initiation, especially in patients with lower levels of Der p SPT (< 5.5 mm) or sIgE (< 2.77 kUA/L).

Responsiveness of Nasal Provocation Testing—But Not Skin Test and Specific Immunoglobulin E Blood Level—Correlates With Severity of Allergic Rhinitis in Dermatophagoides Species-Sensitized Patients

Background The results of skin and blood allergen testing are not consistently relevant to clinical manifestations in allergic patients. Objective The aim of the study was to investigate the relationship between severity of allergic rhinitis and different allergen diagnostic tests in Dermatophagoides species-sensitized patients. Methods Study subjects included 65 rhinitis patients—50 with Dermatophagoides pteronyssinus (DP) sensitization (DP+) and 15 without DP sensitization (DP−), and 15 DP+ and 37 DP− healthy controls (HCs) confirmed by allergen skin prick (SPT) and blood specific immunoglobulin E (sIgE) tests. The Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) was tested. All subjects underwent DP nasal provocation test (DP-NPT). Visual analogue scoring (VAS) of nasal symptoms and nasal airway resistance (NAR) were measured before and after NPT. Correlations between the 3 allergen tests and score of RQLQ were performed. Results All rhinitis subjects had significantly higher VAS and NAR after DP-NPT than HCs ( P < .01). All DP+ rhinitis, 40% of DP− rhinitis subjects, 13.3% of DP+ HCs and 0% of DP− HCs had positive DP-NPT. Dose of positive DP-NPT positively correlated with SPT diameter and sIgE level in all tested subjects ( P < .001). Score of RQLQ positively correlated with dose of DP-NPT ( P < .001), but not with SPT diameter and sIgE level in rhinitis patients. Conclusion Although DP nasal provocation, skin prick wheal size and blood sIgE level correlate with each other, only nasal provocation testing is associated with severity of nasal symptoms. It is suggested that NPT should be performed to verify a clinically relevant allergy.