Can Reflux Medications Cause Allergies?

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Reflux medications are wonderful to treat symptoms of heartburn as well as reflux-triggered throat problems. However, there is growing concern that long-term use of reflux medications is associated with other health problems including nutritional deficiencies along with increased risk of bone fracture, pneumonia, and other infections including Clostridium difficile infection where proton pump inhibitors may carry a high risk equivalent to that of oral antibiotics.

Now a new body of literature published since 2000 suggests that reflux medications may increase risk of allergy development. How? Why?

The argument goes like this...

Because the reflux medications decrease or neutralize stomach acid production, food proteins are not broken down as much as they should be. These larger proteins are able to sensitize the immune system and trigger an allergic reaction in someone with a food allergy. These larger-than-usual protein pieces prime the immune system making an allergic response more likely to other things over time.

In a mouse model, researchers indeed found proteins that were largely intact were much more likely to trigger an allergic reaction in mice than proteins that were degraded by stomach acid. This risk even occurred not only to a pregnant mom but also to the developing fetus.

Researchers in 2019 published that there is an association between reflux medication usage with later allergy medication usage. This finding was based on health insurance claim data covering nearly all of the more than 8 million people in Austria.

On average, someone prescribed a reflux medication was about twice as likely to later be prescribed an allergy medication compared with a person who was never prescribed a reflux medication at all. People over age 60 were five times more likely to get an allergy prescription if they had earlier been prescribed a reflux medication than if they hadn’t (absolute risk of almost 5% versus almost 1%). For those under 20 years old, the risk increase was only about 1.5 times as high (almost 7% versus almost 5%).

Now keep in mind that association does not necessarily mean causation regardless of the rodent research.

Also, not ALL reflux medications are associated with this risk of allergies... only reflux medications that reduce or neutralize stomach acid. But reflux medications (ie, gaviscon advance, esophageal guardian, etc) that work by physically blocking reflux from entering the esophagus would be free from this allergy risk association.

So should a patient with severe reflux or other reflux-related disease conditions take reflux medications? Absolutely if the benefits outweigh the risk. That said, effort should be taken to minimize the long-term duration of taking reflux medications and transition to more lifestyle changes for long-term reflux control. Alternatively, reflux surgery can be considered to try and "cure" reflux to avoid long-term reflux medication usage.

References:
Country-wide medical records infer increased allergy risk of gastric acid inhibition. Nature Communications, Volume 10, Article number: 3298 (2019)

Proton pump inhibitors alter the composition of the gut microbiota. Gut 2016;65:749-756.

Anti-acid medication as a risk factor for food allergy. Allergy 66, 469–477 (2011).

The role of protein digestibility and antacids on food allergy outcomes. J. Allergy Clin. Immunol. 121, 1301–1308 (2008).

Acid-suppressive medications during pregnancy and risk of asthma and allergy in children: a systematic review and meta-analysis. J. Allergy Clin. Immunol. 139, 1985–1988 e1912 (2017).