A sore throat is usually caused by an infection in the throat and airways. A long-lasting sore throat that does not respond to standard treatment can be caused by acid reflux.
What is acid reflux?
Reflux refers to the rise of stomach contents into the esophagus. When the acidic gastric juice irritates the esophagus, it causes typical symptoms such as heartburn. Acid reflux is also known as gastroesophageal reflux disease (GERD).
Reflux can also be gaseous, rising through the esophagus and reaching the airways. This kind of reflux is known as airway reflux, or also as silent reflux because it causes unspecific symptoms, such as a sore throat or hoarseness. Many people with silent reflux don’t realize that their symptoms are caused by the condition, and it can take many years to receive a correct diagnosis.
How acid reflux causes a sore throat
Along with the acidic gases, an enzyme from the stomach, called pepsin, is carried into the throat and airways. Pepsin is essential for digestion because it breaks down proteins. Because it normally resides in the stomach, it is active in a low pH (or acidic) environment, and it is inactive at the typical pH of the throat and airways.
Unfortunately, acid reflux and also acidic foods and drinks can lower the pH in the throat and thereby activate pepsin. Because the cells of the mucous membranes mainly consist of proteins, pepsin breaks down these proteins and thus irritates the mucous membranes, causing inflammation and swelling of the throat and airways.[1] In response to the inflammation, the body also produces mucus.
By this mechanism, acid reflux causes a sore throat, hoarseness, cough and swallowing difficulties.[2]
By irritating the mucous membranes, acid reflux also increases the susceptibility to flu-like infections, and hence, it also increases the likelihood of sore throat through infections.
This article explains in detail how acid reflux damages the mucous membranes.
How to recognize that a sore throat is caused by acid reflux
It is hard to find features that distinguish a sore throat caused by acid reflux from a sore throat through other causes. One vital indicator is the duration: When the sore throat lasts for a long time and is not caused by a cold or other infections, acid reflux is a likely cause.
Acid reflux can cause not only a sore throat but other symptoms as well. By assessing it in combination with other symptoms, the likelihood of acid reflux being the cause can be estimated.
Many doctors use the RSI test to measure the symptoms. The RSI test is a questionnaire to determine the severity of symptoms and the likelihood of acid reflux. You can take the test online on Refluxgate.
Treatment of sore throat caused by acid reflux
A sore throat that is caused by acid reflux cannot be treated with standard pain, flu or cold medication.
To get rid of the sore throat and other symptoms, acid reflux be eliminated as far as possible.
In most cases, acid reflux can be significantly reduced through dietary changes. Because acidic foods and drinks can activate pepsin on their way to the stomach, avoiding them improves symptoms.[3]
Medications that reduce acid production in the stomach, called proton-pump inhibitors (PPIs), are frequently prescribed for silent reflux. These medications can reduce heartburn, but they do not work well for airway symptoms such as a sore throat. The reason is that the damage is not just caused by acid alone but in combination with the stomach enzyme pepsin. Acid suppressing medication does not affect pepsin.
If you want to learn more about how to treat airway reflux with diet, I recommend you to read our specialized article.
References
[1] 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(S53):1-78.
[2] Laryngopharyngeal Reflux (LPR). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15024-laryngopharyngeal-reflux-lpr. Accessed Oct 17, 2019.
[3] Koufman JA. Low-acid diet for recalcitrant laryngopharyngeal reflux: Therapeutic benefits and their implications. Ann Otol Rhinol Laryngol. 2011;120(5):281-7.