Editorial by Godlee

Mrs V was a 66 year old woman who said she had had a non-productive cough almost daily for 20 years. This had been treated unsuccessfully in the past with antibiotics, but she was not taking any medication currently. Mrs V had good exercise tolerance, although she had an occasional wheeze at night. She was a non-smoker and had never lived with smokers. Her chest was normal on examination. Her peak expiratory flow rate was 500 (with a predicted value of 380), and her spirometry result was good and showed minimal (<5%) response to β agonist. Nevertheless, because asthma is an intermittent but common cause of cough, and because Mrs V had complained of nocturnal wheeze, I decided to try her on a β agonist aerosol (an alternative would have been an inhaled steroid, but the response to treatment would have taken longer). Meanwhile, I resolved to track down the evidence about other possible causes of Mrs V's cough.