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The Chronic Cough of Cystic Fibrosis

Chronic, or long-term, coughing is one of the hallmarks of cystic fibrosis (CF). People with CF tend to cough frequently because the mucus their body creates clogs the airways.

Normal lung functioning

In a normal lung, the mucus is thin enough to move along the airways, swept along by cilia, tiny hair-like cells that line the airways in the lungs. Cilia help move out foreign matter such as dust, viruses, bacteria, and fungus. This process keeps the lungs clean and free of germs.

Lung function with cystic fibrosis

In cystic fibrosis, the mucus is too thick for the cilia to move it. This causes coughing, which is the body’s natural way of helping the lungs remove the thick mucus.

The process of coughing up mucus (also called sputum) is called “expectorate.” Usually, only older children and adults can cough up sputum.

Without coughing, the thick, sticky mucus of CF accumulates in the lungs, allowing germs to remain and cause infections that damage the lungs.1

Why vigorous coughing is important

While the chronic cough of people with CF may sound alarming to those who do not understand the disease, vigorous coughing is actually a sign that the respiratory muscles are strong. Without strong muscles to help the lungs clear mucus, infections become more frequent and the lung weaken.2

People with CF should be encouraged to cough and should never suppress a cough or use cough suppressants.3

Acid reflux and cough

It might seem obvious that the thick, sticky mucus of CF would be the main reason for chronic coughing, but acid reflux (also called Gastroesophageal reflux) also plays a role. Sometimes acid reflux progresses to gastroesophageal reflux disease or GERD, a more severe form of reflux.

Gastroesophageal reflux contributes to chronic cough in people with CF because small amounts of stomach acid can get into the lungs, and the body responds with a cough. Acid reflux may contribute to lung damage if left untreated.4

Treatments for chronic cough

A variety of treatments are available to help people with CF cough more productively (cough up more mucus). Some medicines target the cough directly while others are used to treat the underlying cause of thick mucus. These treatments include:

Complications of chronic cough

People with CF sometimes cough so long or so hard that they develop complications. Common complications of a long-term, heavy cough include:

  • Coughing up blood (hemoptysis) due to broken blood vessels in the lungs
  • Rectal prolapse
  • Fatigue6

Other common respiratory symptoms of cystic fibrosis include: Wheezing and shortness of breath, frequent lung infections, and sinus infections.

Written by: Jessica Johns Pool | Last reviewed: September 2019
  1. University of Gothenburg. Mucus, cough and chronic lung disease. ScienceDaily. ScienceDaily, 24 October 2018. Https://www.sciencedaily.com/releases/2018/10/181024095338.htm. Accessed 5/8/2019.
  2. U.S. National Library of Medicine: Clinical Trials.Gov. Cough Efficiency in Cystic Fibrosis. Available at: https://clinicaltrials.gov/ct2/show/NCT01636219. Accessed 5/8/2019.
  3. Cystic Fibrosis Foundation. Introduction to CF. Available at: https://www.cff.org/Intro-to-CF.pdf. Accessed 5/8/2019.
  4. Fathi H, Moon T, Donaldson J. Cough in adult cystic fibrosis: diagnosis and response to fundoplication. Cough, 2009, Vol 5:1:1. Doi.org/10.1186/1745-9974-5-1.
  5. Cystic Fibrosis Foundation. Coughing and Huffing. Available at: https://www.cff.org/Life-With-CF/Treatments-and-Therapies/Airway-Clearance/Coughing-and-Huffing/. Accessed 5/8/2019.
  6. Cystic Fibrosis Foundation. What To Do Before You Start Coughing Up Blood. Available at: https://www.cff.org/CF-Community-Blog/Posts/2018/What-To-Do-Before-You-Start-Coughing-Up-Blood. Accessed 5/8/2019.