In patients with a normal chest xray, 95% of chronic cough is caused by one or more of the following three problems: postnasal drip, asthma and gastroesophageal reflux disease.

Postnasal Drip (PND)

PND is the most common cause of cough. It may be caused by a recent cold, within the past 6 weeks. Other symptoms associated with PND may include:

(1) a feeling of mucous dripping into the throat

(2) frequent throat clearing

(3) nasal congestion or discharge

(4) hoarseness.

PND is usually treated with an oral antihistamine and a nasal spray to decrease mucous production in the back of the nose. It is important to understand that newer, nonsedating antihistamines (such as fexofenadine or Allegra and loratadine or Claritin) seldom relieve cough in patients with PND since they do not dry secretions. These newer antihistamines may be useful for patients with true allergic PND, but that is a less common cause of chronic cough.

Nasal steroid sprays rarely are effective by themselves in treating chronic cough from PND. The sinuses need to be pretreated with Kaiser's saline flush kit (flushing mucus out of the sinuses before applying nasal steroids) or else the nasal steroid sprays merely coat the mucus and do not work.

Asthma

Asthma is the second most common cause of chronic cough. In some patients, cough is the only symptom of asthma (“cough variant asthma”). Other patients may have wheezing, shortness of breath, and a feeling of tightness in the chest. Adult onset asthma is fairly common and can come and go with colds, changes in the weather, or high pollen seasons.

Cough due to asthma usually goes away when the asthma is effectively treated. Asthma is usually treated with one or more inhaled medicines.

Additional information on Asthma

Gastroesophageal Reflux Disease (GERD)

Stomach contents can travel back up the swallowing tube and irritate the airway opening or even get into the bronchial tubes, causing cough, chronic bronchitis and/or asthma

GERD may be difficult to diagnose. Many patients with GERD-related cough do not have typical “indigestion” symptoms such as heartburn, sour taste, or regurgitation.

Treatment of GERD includes dietary restrictions (giving up caffeine, chocolate, alcohol and spicy foods), elevating the head of the bed, and the use of medicines to decrease the production of stomach acid. These therapies may take several weeks to have a full effect on GERD-related cough.

Additional information on GERD