Left untreated, GERD progressively damages the esophagus and can trigger a chain of complications that extends well beyond heartburn. The acid your stomach produces is strong enough to break down food, and when it repeatedly washes back into tissue that wasn’t built to handle it, the consequences range from scarring and narrowing of the esophagus to cellular changes that raise cancer risk. Most of these complications develop slowly over months or years, which means they’re largely preventable with treatment.
Erosion of the Esophageal Lining
The first thing that happens with ongoing reflux is direct damage to the tissue lining your esophagus. Gastroenterologists grade this damage on a four-point scale (A through D) based on how much of the esophageal surface is affected. At the mildest end, you might have small breaks in the lining shorter than 5 millimeters. At the most severe, those breaks cover 75% or more of the esophagus’s inner circumference, often coated in a dense white layer of inflammatory material.
This erosion, called esophagitis, is what causes the burning chest pain most people associate with GERD. But here’s the problem: the damage can worsen silently. Some people adapt to the discomfort or mistake worsening symptoms for something else. When esophagitis is treated with acid-suppressing medication and that medication is stopped, inflammation can return in as little as one week, which illustrates how persistent the underlying condition is.
Scar Tissue and Esophageal Narrowing
Chronic inflammation doesn’t just stay on the surface. Over time, the repeated cycle of damage and healing causes scar tissue to build up within the esophageal wall. This fibrosis gradually narrows the opening, forming what’s called a stricture.
The hallmark symptom is difficulty swallowing solid food that gets progressively worse. Early on, you might notice that dense foods like bread or meat feel like they’re getting stuck. As the narrowing worsens, even softer foods and eventually liquids become hard to get down. Some people experience food impaction, where a bite of food physically lodges in the esophagus and won’t pass. Chest pain, pain while swallowing, and unintentional weight loss are also common. Strictures are treatable (usually with a procedure to stretch the narrowed area), but the underlying reflux has to be controlled to prevent them from returning.
Barrett’s Esophagus: When Cells Change
One of the most significant consequences of long-term GERD is a condition called Barrett’s esophagus, which affects roughly 2% of the general adult population. This is where the damage moves beyond surface erosion into something more fundamental: the cells themselves transform.
Normally, the esophagus is lined with flat, layered cells designed to withstand the friction of swallowing. When these cells are repeatedly exposed to stomach acid and bile, a biological switch gets flipped. The stem cells that regenerate the esophageal lining essentially shut down their normal programming and activate a different one, producing cells that look and behave more like intestinal lining. Acid and bile exposure turns off the genetic signals that maintain normal esophageal cells and turns on signals that drive intestinal-type cell growth. The result is a patchwork of tissue types, including cells that produce mucus and other cell types normally found only in the gut.
Barrett’s esophagus matters because it’s a precancerous condition. These transformed cells can accumulate further genetic damage over time, potentially progressing to esophageal adenocarcinoma. The annual risk of that progression is relatively low, somewhere between 0.12% and 0.6% per year depending on the study, but it’s a risk that accumulates the longer the condition persists. Population-based studies suggest the absolute annual risk may be on the lower end, around 0.12% to 0.14%, but even small annual risks add up over a decade or two of uncontrolled disease.
Damage to the Throat and Voice
Acid doesn’t always stop at the esophagus. When reflux reaches the throat and voice box, it causes a related condition called laryngopharyngeal reflux. The tissues in the throat are even more sensitive to acid than the esophagus, so even small amounts of exposure can cause problems.
Short-term, this shows up as chronic hoarseness, a persistent feeling of something stuck in your throat, or a cough that won’t quit. Left unchecked for years, the damage becomes structural. Acid exposure can cause granulomas (small lumps of inflamed tissue) on the vocal cords, scarring of the vocal folds that permanently alters your voice, and in severe cases, narrowing of the airway below the vocal cords. Chronic laryngopharyngeal reflux is also considered a risk factor for laryngeal cancer.
Lung and Airway Problems
The connection between GERD and lung disease comes down to micro-aspiration, tiny amounts of stomach contents that get inhaled into the airways. Nearly 50% of healthy people aspirate small amounts of throat secretions during sleep, but when those secretions contain stomach acid, the consequences are much more serious.
Aspirated acid triggers inflammation in the lower respiratory tract, producing symptoms like chronic cough, excess mucus, chest discomfort, and hoarseness from laryngeal irritation. Over time, this can contribute to or worsen asthma, cause aspiration pneumonia, and trigger chronic inflammatory changes in the lungs. In some cases, repeated micro-aspiration is linked to lung fibrosis, where inflammation gradually replaces healthy lung tissue with scar tissue.
Tooth Erosion From Acid Exposure
Your teeth are another casualty of uncontrolled reflux. When acid reaches the mouth, it dissolves tooth enamel in a characteristic pattern that dentists can often spot before a patient even mentions digestive symptoms.
The palatal surfaces (the backs) of the upper front teeth are hit first, because that’s where refluxed acid makes initial contact. If reflux continues, the chewing surfaces of the back teeth in both arches begin to erode. Only after prolonged exposure do the outer, visible surfaces of teeth start to break down. Early signs include loss of the natural shine on enamel and a yellowish discoloration as the enamel thins and the underlying tooth structure shows through. Teeth become increasingly sensitive to temperature, sweetness, and pressure. Advanced erosion can reduce the height of teeth enough to change your bite.
Redness and irritation of the soft palate and uvula are also common in people with GERD-related oral damage.
Sleep Disruption and Obesity
GERD and obstructive sleep apnea frequently coexist, and the relationship may run in both directions. In a large study of over 22 million patients with GERD, 12.2% also had sleep apnea, compared to just 4.8% of patients without GERD.
The proposed mechanism works like a feedback loop. Sleep apnea involves increased respiratory effort and airway obstruction, which raises the pressure difference across the valve at the top of the stomach. That extra pressure promotes the valve’s opening and makes reflux more likely. At the same time, GERD symptoms like nighttime coughing and discomfort fragment sleep and may worsen apnea. Obesity is the strongest shared risk factor between the two conditions, partly because excess abdominal weight puts direct pressure on the stomach and promotes the kind of transient valve relaxations that allow acid to escape upward.
When Screening Becomes Important
Current guidelines from the American College of Gastroenterology recommend an endoscopy (a scope exam of the esophagus) for anyone with GERD symptoms who doesn’t respond adequately to an eight-week trial of acid-suppressing medication, or whose symptoms return as soon as the medication stops. An endoscopy is also recommended as the first step for people experiencing difficulty swallowing, unexplained weight loss, or signs of gastrointestinal bleeding, since these alarm symptoms can indicate that complications like strictures or Barrett’s esophagus have already developed.
For the most accurate picture of what’s happening in the esophagus, the scope is ideally done after acid-suppressing medications have been stopped for two to four weeks. This allows any existing erosion to become visible rather than being masked by medication.