[Clinical features of postinfectious chronic cough]

Postinfectious cough has been drawing attention as a factor involved in the etiology of chronic cough in the United States. In Japan, clinical features of postinfectious chronic cough (PICC) have not been described in detail. We investigated 22 patients with PICC diagnosed by the established criteria (Jpn. J. Allergol. 1995; 44: 1418). All patients were nonsmokers and none received ACE inhibitors. None had a history of atopy or sinus diseases. There were four men and 18 women with a median age of 65 years. These 22 patients underwent clinical examinations including chest roentgenograms, respiratory function tests, eosinophil counts in venous blood, serum IgE titers, antibody titers to Mycoplasma pneumoniae, sputum cytologic findings taken from ten patients, and histological features of bronchial biopsy specimens obtained from two patients; all findings were within normal limits. Clinical course of cough in 20 of the patients with PICC was evaluated using a cough diary. One patient did not keep a cough diary. Ten patients improved with dextromethorphan hydrobromide (D) and oxatomide (O). Three of the remaining 9 patients improved with Bakumondo-to (B) only, 4 with D+O+B, and 2 with D+O+B+ozagrel hydrochloride. The duration of cough before treatment showed a significant correlation with the time from the start of treatment to recovery (r = 0.47, p < 0.05). These results indicate that PICC tends to occur in elderly women and to improve with treatment combining with D, O, and B. We hope to establish a standard therapy for postinfectious chronic cough.