Use of mannitol inhalation challenge in assessment of cough

Bronchial provocation testing uses a variety of direct and indirect inhalational challenges to evaluate airway hyperreactivity. Mannitol, a simple, easy-to-administer hypertonic stimulus available in many countries, is currently under review by the FDA in the US. Healthy subjects show no airway response to inhaled mannitol; asthmatic patients respond with airway narrowing similar to challenges with hypertonic saline and exercise. Mannitol challenge also has a tussive effect that is independent of bronchoconstriction, suggesting different physiologic pathways. Patients with chronic cough show increased sensitivity to mannitol, and mannitol testing may be useful for evaluating heterogeneity in the cough response.