Persistent cough or chronic cough is a cough that does not resolve in a few days. Chronic cough is not a disease in itself; rather it is a symptom of other disorders.

It is a common problem in our society that prompts people to visit health facilities.
Some common causes of chronic cough include asthma, allergic rhinitis, sinus problems (for example sinus infection), and esophageal reflux of stomach contents.

In rare occasions, chronic cough may be the result of aspiration of foreign objects into the lungs (usually in children). It is very important to obtain a chest x-ray if a chronic cough is present.

The following pertains to patients who have a normal chest x-ray.
Cigarette smoking is the most common cause of chronic cough.

Asthma is a disease of airways, resulting in difficulty breathing or wheezing often characterized by abnormal breathing tests. Some asthma sufferers have chronic cough as their only symptom.

They may even have normal lung function tests. This is often referred to as cough-variant asthma. Asthma symptoms can be aggravated by cold air, exposure to air pollutants or pollen, smoke, or perfumes.

Gastro esophageal reflux disease refers to backward flow of stomach acid and other contents into the esophagus.

If stomach acid moves backward up the esophagus, reflexes result in spasm (contraction) of the airways that can cause shortness of breath and coughing.

In some instances, reflux can be so severe that substances can be aspirated into the lungs and cause similar symptoms as well as damage to lung tissue. In some individuals, no sensation of heartburn is felt and their only symptom may be cough.

Sinus problems and postnasal drip can also cause chronic cough. This condition can be difficult to detect. Sometimes CT scan of the sinuses is necessary for diagnosis.

Patients often complain of a "tickle in their throat” and frequent throat clearing.
Infections such as bronchitis or pneumonia can cause coughing. These infections can be caused by virus, bacteria or fungus.

Viral infections do not respond to antibiotics. In patients with asthma, viral upper respiratory infections often result in a protracted cough even after the infection has cleared.

Certain medications, notably angiotensin converting enzyme inhibitors such as enalapril (Vasotec), captopril (Capoten) used in treating high blood pressure, can cause chronic cough.

Less common causes can also include tumors, sarcoidosis or other lung disease.
If chronic cough persists a patient should be evaluated by his or her doctor.

It is important to exclude; asthma, postnasal drip, esophageal reflux, drug side effect, interstitial lung disease, or other unusual infections.

Treatment
The treatment of cough is determined by the cause. However, patients may get symptomatic relief from over the counter cough medicines containing guaifenesin and dextromethorphan, drinking lots of water, inhaling steam, and using cough lozenges.

In severe cases a doctor may prescribe codeine, which is an effective cough suppressant.
Asthma; inhaled bronchodilators and inhaled steroids are given to decrease inflammation of the airways.

In some cases, short-term oral steroid drugs are prescribed.
Gastro esophageal reflux disease; treatment includes avoiding foods that increase reflux, avoiding meals before lying down, elevating the head while sleeping, and taking medication such as cimetidine,  ranitidine  to decrease stomach acidity.

Sinus problems and postnasal drip: Use of decongestants such as pseudoephedrine (Sudafed) or antihistamines such as diphenhydramine (Benadryl) may improve symptoms of post nasal drip.

Inhaled nasal steroids are very effective in treating allergic rhinitis (hay fever), a common cause of cough. Additionally, other nasal inhalers like ipratropium bromide (Atrovent) can relieve post nasal drip.

Antibiotics may be prescribed if the cause is determined to be sinusitis.
Infections; bacterial pneumonia and bronchitis are typically treated with antibiotics such as cephalosporins and azithromycin (Zithromax).

If the pneumonia is close to the chest wall inflammation of the surface of the lung can cause pain, known as pleurisy and analgesics can be helpful.

Cough suppressants are used with caution in these situations because clearing the lung of the infected mucus by coughing helps clear the infection.

Most bronchitis in adults is from virus infection; therefore, treatment is much the same as that of the common cold including rest, fluids, analgesics, and humidification.

Medications; Patients taking blood pressure medicines called angiotensin converting enzyme inhibitors  should talk to their doctor about switching medications.

They should not stop their medicines on their own because a marked elevation in blood pressure can result from discontinuation.

A newer generation of angiotensin converting inhibitor for example valsartan (Diovan), losartan (Cozaar) can be alternatives that have less potential to cause chronic coughing.

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