A duodenal ulcer is an open sore that forms in the lining of the duodenum, the first section of your small intestine just beyond the stomach. Over 95% of these ulcers develop within the first few centimeters past the pylorus (the valve connecting your stomach to your small intestine), and most are 1 cm or smaller in diameter. They’re one of the two main types of peptic ulcer disease, the other being gastric ulcers, which form in the stomach itself.
What Causes Duodenal Ulcers
The overwhelming majority of duodenal ulcers are caused by a bacterial infection. A spiral-shaped bacterium called Helicobacter pylori (H. pylori) is responsible for an estimated 85 to 90% of cases. H. pylori burrows into the protective mucus layer that shields your intestinal lining from digestive acid. Once established, it triggers chronic inflammation that gradually erodes the tissue underneath, eventually creating an ulcer.
The second major cause is regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, aspirin, and naproxen. These medications damage the intestinal lining through a two-step process: they weaken the energy production inside the cells of the intestinal wall, which loosens the seals between those cells. Once those seals break down, harsh substances already present in the intestine, including bile acids and digestive enzymes, flood in and trigger inflammation that can progress to an ulcer. Notably, NSAID use and H. pylori infection can work together. Research shows that people who use NSAIDs frequently are significantly more likely to also test positive for H. pylori, and the combination raises ulcer risk beyond either factor alone.
Smoking also plays a role. Nicotine reduces the production of both mucus and bicarbonate, two substances your body uses to neutralize stomach acid and protect the intestinal lining. Alcohol damages the digestive tract in similar ways, impairing those protective barriers.
How Duodenal Ulcer Pain Feels
The hallmark symptom is a dull or burning pain in the upper abdomen. What makes duodenal ulcers distinctive is the timing: the pain often strikes when your stomach is empty or at night, and it typically improves after eating. This is the opposite of gastric ulcers, where eating tends to make the pain worse. The relief after meals happens because food temporarily buffers the acid that’s irritating the exposed sore.
The pain tends to come and go over days or weeks. Some people describe it as a gnawing or hunger-like sensation between meals. Others notice bloating, nausea, or a feeling of fullness. It’s also possible to have a duodenal ulcer with no symptoms at all, particularly in older adults or people taking NSAIDs, which can mask pain.
How Duodenal Ulcers Are Diagnosed
Doctors typically start with your medical history, a physical exam (checking for abdominal tenderness or swelling), and testing for H. pylori. There are several ways to detect the bacterium:
- Breath test: You swallow a capsule or liquid containing a specially labeled form of urea. If H. pylori is present in your digestive tract, the bacteria break down the urea and release carbon dioxide containing the labeled atoms, which shows up when you exhale into a collection container a few minutes later.
- Stool test: A lab checks a stool sample for proteins associated with H. pylori.
- Blood test: Can detect antibodies to H. pylori, though this method is less precise for confirming an active infection.
To confirm the ulcer itself, the most reliable tool is an upper GI endoscopy. A thin, flexible tube with a camera is passed through your mouth and down into the duodenum, allowing the doctor to see the ulcer directly. During the procedure, small tissue samples (biopsies) can be taken and examined under a microscope to check for H. pylori and rule out other conditions. In some cases, doctors may use an upper GI series instead, where you swallow a chalky barium liquid that coats the digestive tract and makes ulcers visible on X-ray.
Treatment and Healing Timeline
Treatment depends on the cause. If H. pylori is present, the standard approach is a combination of an acid-reducing medication (a proton pump inhibitor, or PPI) plus two antibiotics, taken together for about two weeks. This combination clears the infection in the large majority of patients and allows the ulcer to heal. Eliminating H. pylori is essential because without it, ulcers have a high recurrence rate.
If NSAIDs caused the ulcer, the first step is stopping or reducing the medication. A PPI is then prescribed to suppress acid production and give the lining time to repair itself. Most duodenal ulcers heal within four to eight weeks on acid-suppressing therapy. Research suggests that even two weeks of PPI treatment can achieve significant healing, though many doctors prescribe a longer course to be thorough. After treatment, a follow-up breath or stool test can confirm H. pylori has been eradicated.
Foods and Habits That Worsen Symptoms
While food doesn’t cause duodenal ulcers, certain items can irritate an already damaged lining and slow healing. Coffee, including decaffeinated, increases acid production in the stomach. Carbonated drinks do the same while also causing distension that can worsen discomfort. Citrus fruits and their juices (orange, pineapple, passion fruit) add acidity. Spicy peppers, black pepper, and condiments like mustard can irritate the exposed tissue.
Other foods to be cautious with include fatty cheeses, processed meats and sausages, gas-producing vegetables like broccoli, cauliflower, cabbage, and raw onion, and concentrated sweets. Alcohol directly damages the mucosal lining, and smoking impairs your body’s natural repair mechanisms. Quitting smoking and limiting alcohol are two of the most impactful lifestyle changes you can make during recovery.
When Ulcers Become Dangerous
Most duodenal ulcers heal without complications, but untreated or severe ulcers can cause serious problems. The most urgent is perforation, where the ulcer erodes completely through the intestinal wall. This creates a hole that allows digestive contents to leak into the abdominal cavity. A perforated ulcer produces sudden, severe upper abdominal pain, a rigid abdomen, and a rapid heart rate. Within a few hours, the pain spreads across the entire abdomen and worsens with any movement. Beyond 12 hours, fever, abdominal distension, and dangerously low blood pressure can develop. Perforation is a surgical emergency.
Bleeding is the other common complication. An ulcer can erode into a blood vessel, causing anything from slow, chronic blood loss (leading to anemia and fatigue) to rapid hemorrhage that shows up as vomiting blood or passing dark, tarry stools. Less commonly, repeated inflammation and scarring near the pylorus can cause a narrowing called gastric outlet obstruction, which makes it difficult for food to pass from the stomach into the intestine and leads to persistent vomiting and weight loss.