Why Hot, Humid Air Triggers Symptoms in Patients with Mild Asthma

May is asthma awareness month, and with summer right around the corner, a study shows that doctors may be closer to understanding why patients with mild asthma have such difficulty breathing during hot, humid weather. The study, appearing in the June print issue of the American Journal of Respiratory and Critical Care Medicine, found that patients who inhaled an asthma drug before breathing in hot, humid air were able to prevent airway constriction that volunteers without asthma did not experience in the same environment.


Ipratropium, a drug occasionally used for asthma, prevents airway muscle contraction and increases airflow to the lungs. Its success in combating the air temperature response suggests that hot, humid air triggers asthma symptoms by activating airway sensory nerves that are sensitive to an increase in temperature.


“We know that breathing cold, dry air induces airway constriction in asthmatics,” said Don Hayes, MD, medical director of the Lung and Heart-Lung Transplant Program at Nationwide Children’s Hospital. “But the effects that temperature increases have on airway function in these patients are generally overlooked. We know very little about the mechanisms that cause symptoms when asthmatic patients are exposed to hot, humid air.”

Source: http://www.health.am/allergies/more/triggers-symptoms-in-patients-with-mild-asthma/

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