Common causes of persistent cough

What are the most common reasons for a cough lasting longer than 2 months?  The list of possibilities is quite long, but the 4 most common causes are:

1)Upper Airway Cough Syndrome.  Commonly called post nasal drip, this is usually caused by allergies, a sinus infection or a combination of both.  Throat clearing and nasal discharge are typical symptoms. A trial of a decongestant such as Sudafed and an antihistamine like Benedryl will often eliminate the cough.  Antibiotics are added if a physician feels an infection is present.
2)Asthma.  Cough that is worse with exercise or at night is frequently asthma.  Shortness of breath and/or wheezing are not necessary for this diagnosis.  A breathing test to measure lung function (spirometry) is used to confirm asthma, but a trial of an inhaler prescribed by a physician usually helps eliminate this kind of cough.
3)GERD.  Acid reflux frequently irritates the cough reflux.  Daily heartburn and/or regurgitation raises the suspicion for this type of cough, but does not need to be present.  Frequently, an acid reducing medication such as Prilosec is used for 1 to 2 months in an attempt to eliminate this cough.
4)Medication effect.  The blood pressure medication class known as ACE inhibitors causes cough in up to 20% of people.  If a medication such as lisinopril or enalapril is stopped, the cough resolves, usually within 1 to 2 weeks.

Cough lasting longer than 8 weeks is known as chronic cough, and is frequently caused by one or more of the above conditions.  It is essential to see a physician to rule out more serious causes of cough such as lung cancer and heart failure, and to promptly start therapy once the correct diagnosis is made…Richard R Samuel, MD     Family Practice and Urgent Care