Acute cough is usually associated with a common cold or flu. However, when it comes to chronic cough, there is another, often overlooked cause: acid reflux. Patients often see multiple doctors before being diagnosed with acid reflux-related cough.
What is Reflux (GERD)?
Reflux typically refers to the backflow of acidic stomach contents into the esophagus. The irritation of the esophagus by the acid causes characteristic symptoms, most commonly heartburn. This kind of reflux is known as gastroesophageal reflux disease (GERD).
Reflux is usually in liquid form, but it can also be in the form of an aerosol – an almost invisible fine mist that can enter the airways. This kind of reflux is known as laryngopharyngeal reflux (LPR), or also as silent reflux. Cough is one typical symptom, but LPR may also cause sore throat, hoarseness, respiratory problems, and even ear pain.
You can find a detailed description of LPR symptoms in this article.
How Reflux Causes Cough
The gases rising from the stomach carry an enzyme from the stomach called pepsin. Pepsin’s function is to break down proteins as part of the digestive process. Pepsin’s activity is pH-dependent, and it is active at a low (acidic) pH.[1] This makes sense, considering that the stomach environment is acidic.
As already mentioned, pepsin breaks down proteins. Because we consist mainly of proteins, pepsin can cause a lot of damage outside the stomach, as it digests the body tissues instead of the food we eat. This explains why its action in the wrong place is so devastating.[2]
Pepsin in the airways is mostly inactive because it is not an acidic environment. However, gases rising from the stomach are acidic and can thereby activate pepsin. Pepsin can also penetrate the mucous membranes and get reactivated there. Consuming acidic foods and drinks is another important reason pepsin gets reactivated.
The irritation of the mucous membranes causes inflammation, which stimulates mucus production. The coughing helps to remove the excess mucus.
How to Recognize Reflux Cough
It is not easy to recognize that a cough is caused by reflux because there is no difference between a cough caused by reflux and one caused by several other diseases. For instance, asthma and allergies are often misdiagnosed as the cause of cough when reflux is the actual cause.[3]
GERD cough is rarely the only symptom of acid reflux, though. Most people show other signs of airway reflux. The online reflux symptom index (RSI) test helps to assess a range of symptoms that are associated with silent reflux.
This article provides more information about tests for diagnosis of reflux.
Around 25% of chronic cough cases are associated with acid reflux.[4] Acid reflux cough is often stronger after meals, although this is not the case for everybody.
Treatment of Reflux Cough
To get rid of the cough, the cause has to be eliminated.
Successful treatment has to target the cause of reflux. At the same time, symptoms can be reduced by avoiding acidic foods and drinks to avoid the reactivation of pepsin.
Reflux that irritates the esophagus and causes heartburn is typically treated with proton pump inhibitors (PPIs). While this treatment is a good option for GERD, it is not very effective in airway reflux. PPIs only reduce acid production, but they cannot stop pepsin from reaching the airways, where it is activated by acidic foods and then causes damage.
Dietary changes tackle both reflux triggers. They can reduce the reflux itself, while at the same time minimizing the activation of pepsin. For this reason, dietary adaptations can significantly reduce symptoms such as GERD reflux cough in most cases.
In my online course about the treatment of LPR, you can learn precisely which dietary measures you can take to eliminate your reflux cough.
References
[1] Johnston N, Dettmar PW, Bishwokarma B, Lively MO, Koufman JA. Activity/stability of human pepsin: implications for reflux attributed laryngeal disease. Laryngoscope. 2007;117(6):1036–9.
[2] Koufman JA. The otolaryngologic manifestations of gastroesophageal reflux disease (GERD): a clinical investigation of 225 patients using ambulatory 24-hour pH monitoring and an experimental investigation of the role of acid and pepsin in the development of laryngeal injury. Laryngoscope. 1991;101 (4 Pt 2 Suppl 53):1–78.
[3] Koufman, J. IN or OUT? — Asthma that isn’t asthma. The Voice Institute of New York. http://www.voiceinstituteofnewyork.com/in-vs-out-asthma-that-isnt-asthma/. Accessed Nov. 15, 2019.
[4] Madanick RD. Management of GERD-related chronic cough. Gastroenterol Hepatol (NY). 2013;9(5):311–3.