Thresholds in Nasal Histamine Challenge in Patients with Allergic Rhinitis, Patients with Hyperreflectory Rhinopathy, and Healthy Volunteers

Background Characteristic symptoms of hyperreflectory rhinopathy include recurrent sneezing, nasal obstruction, and nasal secretion without an allergic background. The diagnosis can only be made if all differential diagnoses have been excluded. So far no clinical test has been established to reliably diagnose hyperreactivity of the nasal mucosa. The present study aimed to investigate whether nasal provocation with histamine allows identification of patients with hyperreflectory rhinopathy. Materials and Methods One-sided nasal challenge with histamine was applied to 13 patients with allergic rhinitis, 13 patients with hyperreflectory rhinitis, and 12 healthy volunteers. Histamine concentrations used were 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 mg/mL. Test results were quantified using a symptom score (positive at values above 3) and active anterior rhinomanometry (positive at a reduction of airflow of 40% or more in comparison to challenge with solvent). Results While there was a significant difference between controls and patients with allergic rhinitis or hyperreflectory rhinopathy, respectively, no significant difference was observed between the two groups of patients. Results indicated that one-sided nasal provocation with histamine at a concentration of 1 mg/mL is sufficient to separate healthy subjects from patients with hyperreactivity of the nasal mucosa. In terms of the differentiation between subjects with hyperreactivity of the nasal mucosa and healthy controls, the sensitivity of one-sided nasal histamine provocation with 1 mg/mL was found to be 100%; its specificity was 83% if it was evaluated by rhinomanometry and symptom score. Conclusion The present results indicate that one-sided nasal challenge with histamine at a concentration of 1 mg/mL is sufficient to separate healthy subjects from patients with hyperreactivity of the nasal mucosa. However, the test does not differentiate between patients with allergic rhinitis and patients with hyperreflectory rhinitis.