Asthma is characterized by chronic inflammation of the airways. Acute obstruction of the airways causes shortness of breath. Another typical asthma symptom is cough.[1]
Asthma can be caused by allergies, but in many cases, the cause is unknown. There is a strong association between asthma and gastroesophageal reflux. Reflux can cause or worsen asthma.[2]
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 – practically an invisible fine mist which 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, asthma, hoarseness, respiratory problems, and even ear pain.
You can find a detailed description of LPR symptoms in this article.
The Connection Between Reflux and Asthma
The relationship between asthma and gastroesophageal reflux is not entirely understood, but it seems like each of the two conditions favors the development of the other respective condition.
The relationship works in both directions. Reflux can cause asthma, but asthma can also cause reflux.
1) How asthma can promote reflux
Strong coughs, like that occurring in asthma, can promote reflux. The mechanism is not understood in detail, but it seems likely that coughing causes a relaxation of the valve at the lower end of the esophagus, the lower esophageal sphincter.[3] The sphincter acts as a barrier against reflux, and so when it is relaxed, reflux can pass through it more easily.
Asthma medications can also favor the development of reflux. β-agonists and theophylline are commonly prescribed medications against shortness of breath, and they can cause a relaxation of the esophageal sphincters.[4]
2) How reflux can promote asthma
Reflux cannot only reach the esophagus but can also rise further into the throat and airways. This kind of reflux is known as silent reflux, or laryngopharyngeal reflux (LPR). Silent reflux causes unspecific symptoms such as cough and respiratory problems, which may resemble asthma symptoms.[5] The symptoms resemble each other so closely that silent reflux is commonly misdiagnosed as asthma.[6],[7]
When gaseous reflux reaches the lungs of asthma patients, it can also further irritate the already-sensitized airways and aggravate asthma symptoms.[8]
In cases where reflux aggravates asthma symptoms, treatment for reflux is likely to improve the situation.
How to Recognize Reflux Associated Asthma
It is not easy to recognize that a patient’s asthma is caused by reflux. For that reason, asthma is often misdiagnosed as the cause of cough when reflux is the actual cause.[9]
However, acid reflux asthma rarely is the only symptom of airway reflux. Most people show other signs. The online reflux symptom index (RSI) test helps to assess a range of symptoms that are associated with silent reflux.
Also, there are different methods to diagnose airway reflux. You can find out more about diagnosis of airway reflux in this article.
References
[1] Subbarao P, Mandhane PJ, Sears MR. Asthma: epidemiology, etiology and risk factors. CMAJ. 2009;181(9):E181–90.
[2] Mastronarde JG. Is there a relationship between GERD and asthma? Gastroenterol Hepatol (NY) 2012;8(6):401–3.
[3] Mastronarde JG. Is there a relationship between GERD and asthma? Gastroenterol Hepatol (NY) 2012;8(6):401–3.
[4] Richter JE. Gastroesophageal reflux disease and asthma: the two are directly related. Am J Med. 2000;108(4) Suppl 4a:153S–158S.
[5] 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 Oct 11, 2019.
[6] Vaezi MF. Atypical manifestations of gastroesophageal reflux disease. MedGenMed. 2005;7(4):25.
[7] Gaude GS. Pulmonary manifestations of gastroesophageal reflux disease. Ann Thorac Med. 2009;4(3):115–23.
[8] Mathew JL, Singh M, Mittal SK. Gastro-oesophageal reflux and bronchial asthma: current status and future directions. Postgrad Med J. 2004;80(950):701–5.
[9] 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 Oct 11, 2019.
