Subfreezing air as a cough trigger and multiple triggers are strongly associated with the presence of asthma in chronic cough.

BACKGROUND

Management of chronic cough relies on the recognition of cough background disorders. It is not known whether certain cough triggers are associated with specific background disorders.

METHODS

This was an e-mail study to public service employees of two towns in Finland. The questionnaire included twelve triggers. Current asthma was defined as doctor's diagnosis of asthma and current wheezing. Chronic rhinosinusitis was defined as either nasal blockage or nasal discharge and either facial pain/pressure or reduction/loss of smell for more than three months. Gastroesophageal reflux disease was defined as heartburn and/or regurgitation on at least one day a week during the last three months. Idiopathic cough was defined as absence of any of them.

RESULTS

There were 421 subjects with current cough that had lasted at least eight weeks. Subfreezing air as a cough trigger was associated with an adjusted odds ratio (aOR) of 7.27 (4.09-12.9), (p < 0.001), for current asthma. The number of cough triggers was largest in asthma, followed by chronic rhinosinusitis, gastroesophageal reflux, and idiopathic cough (7.05 (6.14-7.96), 4.94 (4.35-5.54), 4.60 (3.77-5.43), and 3.44 (3.02-3.86), respectively, p < 0.001). Presence of five or more triggers was associated with an aOR of 7.49 (3.96-14.2), (p < 0.001) for current asthma. Absence of any cough triggers increased the probability of idiopathic cough (aOR 2.71 (1.54-4.77), p = 0.001).

CONCLUSIONS

Subfreezing air as a cough trigger and multiple triggers are strongly associated with the presence of current asthma in chronic cough. Absence of any cough triggers increases the probability of idiopathic cough.