Effect of airway infections on bronchial reactivity.

The pathological changes in the airway epithelium of patients with asthma and viral upper respiratory tract infection is similar. We have shown that such infections temporarily increase the airway reactivity to histamine and lower the threshold for citric acid-induced cough in normal subjects. We have postulated that sensitisation of airway irritant receptors played a part in this phenomena. Other workers have confirmed these results and in dogs with airway infections an exaggerated discharge of irritant receptors has been shown in response to histamine challenge.