The Different Causes of a Cough

Man coughing at visit with a doctor.
Man coughing at visit with a doctor. Cultura RM Exclusive/Jason Butcher/Getty Images

Coughing is a natural reflex that is important in keeping your lungs and airways clear and functioning properly. While coughing is often not bothersome, a persistent cough that does not seem to go away is both bothersome and may be related to an illness.

There are 3 different types of coughs: acute, subacute and chronic.

Acute Coughs and Their Causes

Acute coughs usually only last up to about 3 weeks and are usually caused by a virus.

This cough may be either productive (produces mucus) or non-productive (dry, no mucus). An acute cough is usually caused by the following illnesses:

Unfortunately, studies have not found existing treatments for acute coughs to be effective. In fact, there is a movement away from even using cough suppressants to ease your symptoms unless a cough is causing other problems.

If the cause is a treatable bacterial infection like pneumonia, then antibiotics would be the proper treatment to help fight the underlying cause of a cough. In most cases of an acute cough, however, the cause is a virus and your body must fight off the infection on its own. Talk to your doctor about your specific circumstance and if any treatment options will be beneficial for you.

Conditions Causing Subacute Cough

Subacute coughs typically last between 3 to 8 weeks.

A subacute cough may need to be evaluated by a physician depending upon the severity of symptoms, as 60% of subacute coughs spontaneously resolve. In other words, there's a pretty good chance of a subacute cough going away on its own.

Common causes of a subacute cough include:

  • A post-infectious cough (most common)

If your physician suspects that the cause of your subacute cough is a post-infectious cough or postnasal drip, he may prescribe antihistamines plus a decongestant (such as chlorpheniramine and pseudoephedrine) for approximately 3 weeks to see if a cough will clear up.

Conditions Causing Chronic Cough

Chronic coughs last longer than 8 weeks. Causes of a chronic cough can sometimes be difficult to pin down. To help isolate the cause of your chronic cough, your doctor may find it necessary to run several tests or even recommend that you see another specialist.

The most common cause of a chronic cough is smoking, however other common causes include:

If you are a smoker, it is important for you to begin a smoking cessation program. Smoking not only will likely be the cause of your chronic cough but will also put you at risk of developing other health-related disorders. Get started today.

Treatment is targeted to the specific cause of a cough. Your physician will take a thorough history to look for likely causes of a cough.

If you are on ACE inhibitors for blood pressure, your physician may have you try an alternative medication to see if your cough resolves.

Your doctor might also want a chest x-ray and another test called spirometry to help figure out the cause of your cough. If the chest x-ray is abnormal, a high-resolution CT scan of the lungs and/or a bronchoscopy may be necessary.

Unfortunately, there are not many physicians willing to specialize in a chronic cough. Initially, you may find that you are referred to a pulmonologist to "work-up" or diagnose a chronic cough, but many of the best pulmonologists may be unwilling to see patients for a chronic cough and refer you to either a gastroenterologist or back to your primary care physician (PCP).

Finding a physician you like that is willing to be patient is probably the key to success in treating your chronic cough.

When A Cough Is An Emergency

Because our cough reflex is natural and protective, sometimes it is our bodies way of letting us know of an impending emergency. If you have a sudden bout of coughing and have the potential for any of the following disorders, you should seek medical attention immediately.

  • Allergic reaction (anaphylaxis)
  • Asthma or COPD exacerbation, when medications can't control the symptoms
  • Inhalation of a foreign object
  • Pertussis
  • Pneumonia

In addition to coughing, you may also experience difficulty breathing, or other worrisome symptoms such as swelling of the tongue.

If you have problems breathing, especially if you are at risk for any of these emergent conditions you should not delay seeking medical treatment, as these can be life-threatening conditions.

Sources:

First Consult. (2013). Evaluation and management of a cough in adults.  https://www.clinicalkey.com (Subscription Required)

Irwin, R.S., Baumann, M.H., Bolser, D.C., Boulet, L., et. al. Diagnosis and Management of Cough Executive Summary: ACCP Evidence-Based Clinical Practice Guidelines. Chest 2006;129;1S-23S. 

Kwon, N., Oh, M., Min, T., Lee, B., and Choi, D. Causes and Clinical Features of Subacute Cough. Chest 2006;129;1142-1147. 

National Heart Lung and Blood Institute. Cough

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