Nonspecific hyper-reactivity and localized allergy: Cause of discrepancy between skin prick and nasal provocation test

Objective. Disagreement between results of skin prick test (SPT) and nasal provocation tests (NPT) causes difficulty in differential diagnosis of allergic rhinitis (AR) and nonallergic rhinitis (NAR). We hypothesized this discrepancy could be due to the nonspecific hyper-reactivity (NHR) and localized allergy of the nasal cavity. Study Design. Prospective pilot. Setting. Academic tertiary rhinologic practice. Subjects and Methods. Sixty patients with AR and 62 with NAR were enrolled. We categorized patients according to results of SPT and NPT. We compared: (1) the clinical characteristics and severity of the disease, (2) change of minimal cross-sectional area (MCA) and total nasal volume (TNV) after normal saline (NS) challenge, and (3) change of nasal symptoms and acoustic parameters after intranasal house dust mite (HDM) challenge between groups. Results. Patients in groups A (SPT[1]/NPT[1]) and C (SPT[-]/ NPT[1]) complained of more persistent discomfort than those in groups B (SPT[1]/NPT[-]) and D (SPT[-]/NPT[-]). The proportion of moderate to severe symptoms was significantly higher in groups A, B, and C compared to group D. After NS challenge, MCA/TNV showed a significantly greater decrease in groups A (MCA: 27.6% 6 21.3%, TNV: 24.6% 6 16.4%) and C (MCA: 31.2% 6 24.0%, TNV: 24.1% 6 23.4%) compared to groups B (MCA: 0.1% 6 13.2%, TNV: 3.9% 6 13.5%) and D (MCA: 2.1% 6 12.1%, TNV: 2.0% 6 17.2%) (P < .05). After HDM challenge, groups A/B showed a greater decrease in MCA (Group A: 62.4% 6 16.1%, Group B: 6.4% 6 11.3%) compared to groups C/D (Group C: 45.5% 6 14.4%, Group D: -3.0% 6 9.5%). Conclusion. NHR and/or localized allergy should be considered in patients with rhinitis whose SPT and NPT results are not in agreement.