Breathing hot humid air induces airway irritation and cough in patients with allergic rhinitis.
We studied the respiratory responses to an increase in airway temperature in patients with allergic rhinitis (AR). Responses to isocapnic hyperventilation (40% of maximal voluntary ventilation) for 4min of humidified hot air (HA; 49°C) and room air (RA; 21°C) were compared between AR patients (n=7) and healthy subjects (n=6). In AR patients, cough frequency increased pronouncedly from 0.10±0.07 before to 2.37±0.73 during, and 1.80±0.79coughs/min for the first 8min after the HA challenge, but not during the RA challenge. In contrast, neither HA nor RA had any significant tussive effect in healthy subjects. The HA challenge also caused respiratory discomfort (mainly throat irritation) measured by the handgrip dynamometry in AR patients, but not in healthy subjects. Bronchoconstriction was not detected after the HA challenge in either group of subjects. In conclusion, hyperventilation of HA triggered vigorous cough response and throat irritation in AR patients, indicating the involvement of sensory nerves innervating upper airways.
Department of Internal Medicine, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536, United States.
Mehdi
M
Khosravi
Pulmonary Function Laboratory, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536, United States.
Paul B
PB
Collins
Department of Physiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536, United States.
Ruei-Lung
RL
Lin
Departments of Pediatrics and Internal Medicine, Ohio State University, 460 West 12th Avenue, Columbus, OH 43210, United States.
Don
D
Hayes
Center for Respiratory and Allergy, University of Manchester, Manchester, Southmoor Road, Manchester M23 9LT, United Kingdom.
Jaclyn A
JA
Smith
Department of Physiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536, United States. Electronic address: lylee@uky.edu.
Lu-Yuan
LY
Lee
D000328:Adult; D000388:Air; D000403:Airway Resistance; D002245:Carbon Dioxide / Q000378:metabolism; D003371:Cough; D005260:Female; D005541:Forced Expiratory Volume; D018737:Hand Strength; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D006813:Humidity / Q000009:adverse effects*; D006985:Hyperventilation / Q000503:physiopathology; D007830:Larynx / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053581:Muscle Strength Dynamometer; D010147:Pain Measurement / Q000379:methods; D012119:Respiration; D012129:Respiratory Function Tests; D065631:Rhinitis, Allergic / Q000503:physiopathology*; D055815:Young Adult
D002245:Carbon Dioxide
Airway irritation; Allergic rhinitis; Cough; Laryngeal; TRPV1