earing in mind that the ultimate confirmation of a diagnosis is the response to therapy,3 we reassessed patients after treatment of the presumed trigger of cough. Asthma/CC+ patients were excluded because they needed ICSs, which would have obscured the effect of treatment of upper airway disease on both symptoms and airway responsiveness. As shown in Table V, treatment produced a significant improvement of cough and of laryngeal and bronchial histamine thresholds. The maximum effect was found in the PR/CRS class, where treatment resolved LHR in 78 of 99 patients and BHR in 29 of 48 patients. This finding suggests that in 60% of the patients, BHR was triggered by upper airway receptors made hypersensitive by rhinitis and sinusitis, which is in agreement with our prior findings.14 Cough and airway thresholds were also significantly improved in the GERD class by means of PPI treatment, whereas in the UNEX class empiric PPI and antihistamine treatment was totally ineffective. Only in 14% of the patients, 18 with PR/CRS and 4 with UNEX, did cough and airway hyperresponsiveness persist after treatment. We can suppose that at least the patients with PR/CRS had unrecognized asthma but had not yet experienced symptoms. In most of these patients with PR/CRS, the addition of ICSs resolved cough, BHR, and LHR.