GERD doesn’t always look like much from the outside, which is part of what makes it frustrating. About 14% of adults worldwide live with it, and for many, the most common finding when a doctor actually looks inside the esophagus is completely normal-appearing tissue. But when GERD does leave visible marks, they show up in several places: inside the esophagus, in the throat, and even on your teeth.
What You Might Notice Yourself
The classic experience of GERD is a burning sensation behind the breastbone, often after meals or when lying down, sometimes accompanied by the taste of stomach acid in the back of your throat. But GERD doesn’t always announce itself this way. Some people never feel heartburn at all. Instead, they develop a chronic cough, hoarseness, the sensation of a lump in the throat, or chest pain that mimics a heart problem. These are considered atypical presentations, and people with these symptoms are actually less likely to have visible damage inside the esophagus.
There’s one external sign that can be surprisingly telling: your teeth. Stomach acid that repeatedly reaches the mouth erodes the palatal surfaces of the upper front teeth, meaning the backs of those teeth, the side facing your tongue. A dentist may spot this pattern before you ever suspect reflux. In some cases, tooth erosion is the only visible clue that GERD is present.
What the Esophagus Looks Like on Endoscopy
When a gastroenterologist passes a tiny camera down your throat during an upper endoscopy, they’re looking for specific patterns of damage to the esophageal lining. The most recognized grading system, called the Los Angeles classification, sorts what they find into four levels of severity.
- Grade A: Small breaks in the lining, each no larger than 5 mm, confined to the ridges (folds) of the esophageal wall. These are so minor that experts now consider them insufficient on their own to confirm a GERD diagnosis, since they can appear in people without the condition.
- Grade B: Breaks longer than 5 mm but still limited to individual folds. Scarring may also be visible as a sign of repeated injury and healing over time. Combined with typical symptoms and a response to acid-suppressing medication, Grade B is generally enough to confirm GERD.
- Grade C: Erosions that bridge across multiple folds but cover less than three-quarters of the esophagus’s inner circumference. This level is considered virtually always diagnostic of GERD.
- Grade D: Erosions that extend around more than three-quarters of the circumference, forming near-complete circular damage. This is the most severe form.
Here’s the key detail many people don’t expect: for the majority of patients who undergo endoscopy for GERD symptoms, the esophagus looks entirely normal. This is called non-erosive reflux disease. The acid exposure is real and the symptoms are real, but the tissue hasn’t broken down in a way that’s visible to the camera. To confirm the diagnosis in these cases, doctors typically use a separate test that measures acid levels in the esophagus over 24 to 48 hours.
What GERD Looks Like in the Throat
When stomach acid travels past the esophagus and reaches the voice box and throat, the condition is called laryngopharyngeal reflux, sometimes referred to as “silent reflux” because many people with it don’t feel traditional heartburn. A doctor examining the throat with a small scope will look for a set of telltale signs: redness and swelling, particularly in the back of the larynx near where the vocal cords meet (called the posterior commissure). That area can become thickened and raised from chronic irritation.
The vocal cords themselves often appear swollen. In more advanced cases, small growths called granulomas can form on the vocal cords, and excess thick mucus coats the larynx. None of these findings are unique to reflux, though. Allergies, smoking, and infections can cause similar-looking changes, which is one reason this type of reflux can be tricky to diagnose on appearance alone.
Barrett’s Esophagus: A Complication You Can See
Years of acid exposure can cause the cells lining the lower esophagus to change their identity. Instead of the pale, smooth tissue that normally lines the esophagus, a doctor sees salmon-pink tongues of tissue creeping upward from the junction where the esophagus meets the stomach. This is Barrett’s esophagus, and its color difference is striking enough to spot during a routine endoscopy. The pink extensions replace what should be lighter-colored tissue, and they can range from very short segments to long stretches.
Barrett’s matters because it’s considered a precancerous change, carrying a small but real risk of progressing to esophageal cancer. A Barrett’s segment longer than 3 cm with certain cell changes confirmed on biopsy is itself considered proof that GERD exists, no further acid testing needed.
Hiatal Hernia: A Structural Clue
During endoscopy, doctors frequently find a hiatal hernia in GERD patients. This looks like a pouch of stomach tissue that has slid upward through the opening in the diaphragm. On the camera, the doctor can see the junction between the esophagus and stomach sitting above the point where the diaphragm should be pinching things closed. Larger hernias are easy to spot both on endoscopy and on barium swallow X-rays. A hiatal hernia doesn’t guarantee GERD, but it weakens the barrier that normally keeps acid in the stomach, making reflux more likely.
How GERD Looks Different From Similar Conditions
One condition that can mimic GERD both in symptoms and under a microscope is eosinophilic esophagitis, an allergic condition of the esophagus. The visual differences during endoscopy are distinctive. While GERD typically produces erosions and redness, eosinophilic esophagitis tends to create a different pattern: concentric rings that give the esophagus a ribbed appearance (sometimes called trachealization), vertical grooves called linear furrows running along the esophageal wall, and small white plaques or patches. The esophagus can also appear narrowed overall, and the tissue sometimes has a fragile, crêpe-paper texture that tears easily when touched.
GERD patients are far more likely to have a hiatal hernia visible during the exam (about 26% versus 7% in one large comparison), while rings, furrows, and white plaques strongly point toward eosinophilic esophagitis. In about one in five cases of either condition, the esophagus looks completely normal on camera, which is why biopsies are often taken regardless of what the scope shows.
What Biopsies Reveal Under a Microscope
When tissue samples from the esophagus are examined under magnification, GERD creates a recognizable pattern. The deepest layer of cells in the lining starts to multiply faster than normal, thickening in response to repeated acid injury. The tiny spaces between cells widen, a change called dilated intercellular spaces, which is thought to allow acid to penetrate deeper into the tissue and trigger pain signals. Inflammatory cells, including a type of white blood cell called eosinophils, may infiltrate the tissue. Occasionally, small ulcerations appear. These microscopic changes can exist even when the esophagus looks perfectly normal through the endoscope, which is one reason biopsies can be valuable in ambiguous cases.