Asthma and GERD are both common diseases in the Western world. They are, however, very different diseases, with very different causes.
GERD is a disease of the gastroesophageal system, or, the system that comprises the esophagus and stomach. This disease develops due to a dysfunction in the lower esophageal sphincter, a ring of muscle that acts as a valve to separate the esophagus and stomach. Normally this ring is almost always closed, and opens only to allow the passage of food and liquid. In someone with GERD, the valve can open in response to certain types of food and other triggers, causing frequent attacks of severe acid reflux.
Asthma is an allergic disease of the respiratory system, caused by an overactive immune response to particles such as pollen and pet hair. In someone with asthma, exposure to triggers causes an immune response that leads to respiratory symptoms such as coughing, wheezing, and breathing difficulty.
It seems counter-intuitive that asthma and GERD are related in any way, but in fact, GERD is a common trigger of asthma symptoms in people who have both conditions.
How does GERD Trigger Asthma Symptoms?
The answer to this question is actually unknown—scientists don’t yet know how and why GERD triggers symptoms of asthma. There are, however, plenty of theories, with two in particular being the most likely current contenders.
One theory is that chronic acid reflux caused by GERD leads not only to esophageal damage, but also to airway and lung damage. This can occur because regurgitated acid can sometimes be aspirated, meaning that the acid is breathed into the airways. If this occurs, symptoms such as airway and lung inflammation, narrowing of the airways, and mucus production, can result.
The second theory is that in someone with GERD, the entry of acid into the esophagus triggers a nerve reflex that causes narrowing of the airways to prevent the entry of acid. This airway narrowing causes shortness of breath, pain, and chest tightness.
More Facts about Asthma and GERD
An estimated 75% of people with asthma also have GERD
Around one third of people with both conditions list GERD attacks as a trigger for asthma symptoms.
If you have asthma, you are twice as likely to develop GERD as someone who doesn’t have asthma.
Someone with severe chronic treatment-resistant asthma has a greatly increased risk of GERD over someone with a milder form of asthma.
Coping with Asthma and GERD
Controlling asthma or GERD alone isn’t always easy, but things are made even more difficult when the two diseases occur together.
One of the most crucial aspects for someone with both diseases is working with his or her doctor to determine the best medications to use. This is important because one type of asthma medication, called beta-adrenergic bronchodilators, can exacerbate GERD symptoms. The reason why this occurs is unknown, but it does demonstrate that it can sometimes be difficult to formulate a workable medication regimen.
Another important factor is controlling triggers of both GERD and asthma, by limiting exposure to allergens, using medication as and when needed, and following a GERD diet if necessary.
Allergy Healthcare: Gastroesophageal Reflux: A Frequent Trigger of Asthma (PDF)
The Cleveland Clinic: GERD and Asthma