An ulcer that won’t close despite treatment usually has an identifiable barrier standing in the way. For stomach and intestinal ulcers, that barrier is often an ongoing infection, a medication you’re still taking, or an underlying condition driving excess acid. For skin ulcers on the legs or feet, poor circulation, uncontrolled blood sugar, or nutritional gaps are the most common culprits. A peptic ulcer is formally considered “refractory” if it hasn’t healed completely after 8 to 12 weeks of standard acid-suppressing medication.
H. pylori That Resists Treatment
The bacterium H. pylori causes the majority of peptic ulcers, and eradicating it is essential for healing. The problem: antibiotic resistance is increasingly common. Globally, roughly 33% of H. pylori strains are resistant to clarithromycin, one of the most widely prescribed antibiotics for this infection, and about 35% resist metronidazole, another frontline drug. In some regions resistance is far higher. In parts of East Asia, clarithromycin resistance runs above 40%, and in parts of the Middle East metronidazole resistance exceeds 60%.
If you completed a course of antibiotics for H. pylori but your ulcer persists, the infection may still be active. A follow-up breath test or stool test can confirm whether the bacteria survived. When a first-line regimen fails, doctors typically switch to a different combination of antibiotics rather than repeating the same one.
Pain Relievers That Block Healing
NSAIDs like ibuprofen, naproxen, and aspirin are one of the most common reasons an ulcer stalls. These drugs suppress the production of prostaglandins, which are chemical signals your stomach lining depends on to maintain blood flow, secrete protective mucus, and regenerate new cells. In animal studies, tissue around an ulcer treated with NSAIDs showed roughly one-third the number of dividing cells compared to tissue healing without the drug. That’s a dramatic slowdown in the repair process.
The tricky part is that many people take NSAIDs for chronic pain conditions and don’t realize these medications are undermining their ulcer treatment. Even low-dose aspirin prescribed for heart protection can delay healing. If you’re taking any NSAID regularly, that’s likely the first thing your doctor will address. Alternatives for pain management exist, and removing the NSAID often allows healing to resume.
Smoking Slows Blood Flow to the Stomach
Smoking cuts mucosal blood flow in the stomach nearly in half. One study measured gastric blood flow dropping from a median of 66 ml/min to 36 ml/min during cigarette smoking. Your stomach lining needs that blood supply to deliver oxygen and nutrients to the ulcer site, flush away acid, and support cell growth. Smoking also reduces bicarbonate secretion in the duodenum, weakening the chemical buffer that neutralizes acid as it leaves the stomach.
Quitting doesn’t just remove a risk factor for getting ulcers. It restores the conditions your body needs to close an existing one.
Conditions That Drive Excess Acid
Sometimes the ulcer isn’t healing because something is pushing your stomach to produce far more acid than normal. Zollinger-Ellison syndrome is a rare but important example. It’s caused by a tumor (called a gastrinoma) that secretes gastrin, the hormone that triggers acid production. Normal fasting gastrin levels sit below 100 pg/mL. Levels above 300 pg/mL are suspicious, and levels above 1,000 pg/mL combined with very acidic stomach contents are considered diagnostic. Standard doses of acid-suppressing medication simply can’t keep up with the acid output these tumors drive.
Crohn’s disease can also produce ulcers in the stomach and duodenum that mimic ordinary peptic ulcers but don’t respond to typical treatment. Upper gastrointestinal involvement occurs in roughly 0.5% to 5% of Crohn’s patients, though the true number may be higher since many adults with Crohn’s don’t routinely get upper endoscopy.
Hidden Malignancy
About 5% of gastric ulcers that look benign on initial endoscopy turn out to be cancerous. This is one of the key reasons doctors recommend follow-up endoscopy for stomach ulcers that don’t heal on schedule. A gastric ulcer that shrinks but never fully closes, or one that looks unusual in shape or has raised edges, warrants repeat biopsy. Duodenal ulcers carry a much lower malignancy risk, so this concern applies primarily to ulcers in the stomach itself.
Diabetic Foot Ulcers and Blood Sugar
For foot ulcers related to diabetes, blood sugar control is one of the strongest predictors of whether the wound will heal or progress toward amputation. The current evidence points to an HbA1c between 7% and 8% as the target range that best supports healing. Below that range, aggressive glucose control hasn’t shown additional healing benefits and introduces risks from low blood sugar episodes. Above 8%, elevated glucose fuels a cycle of inflammation, damages small blood vessels, and impairs the immune response at the wound site.
High blood sugar also generates compounds called advanced glycation end-products that accumulate in tissue and trigger persistent inflammation, essentially locking the wound in its early inflammatory phase instead of progressing to repair. Continuous glucose monitoring can help maintain the tighter control these wounds demand.
Poor Circulation in Leg Ulcers
Venous leg ulcers, the open sores that form around the ankles when leg veins don’t return blood efficiently, have a well-established healing bottleneck: lack of compression. In pooled clinical data, 61% of venous ulcers healed with compression therapy compared to 39% without it. That translates to a 55% greater likelihood of healing simply from consistent use of compression bandaging or stockings.
If you have a leg ulcer that’s been dressed and cleaned regularly but isn’t closing, inadequate compression is one of the first things to evaluate. Arterial disease in the legs can also stall healing, but it requires the opposite approach, since compression can be harmful when arteries rather than veins are the problem. A simple ankle blood pressure test can help distinguish between the two.
Nutritional Gaps That Stall Repair
Your body needs specific raw materials to rebuild tissue, and deficiencies are surprisingly common in people with chronic wounds. Vitamin C is essential for collagen production, the structural protein that forms the scaffold of new tissue. In one study of patients with diabetes-related foot ulcers, 86% had substantial vitamin C deficiency, compared to 25% of people with diabetes who didn’t have foot ulcers. Zinc supports cell division and immune function at the wound site, and vitamin D plays a role in controlling inflammation.
These deficiencies are easy to test for with a blood draw and relatively straightforward to correct, yet they’re often overlooked when the focus is on wound dressings and medications alone. If your ulcer has plateaued despite appropriate treatment, nutritional status is worth investigating.
What Happens When an Ulcer Stays Refractory
When a peptic ulcer remains open after 8 to 12 weeks of acid-suppressing therapy, the diagnostic workup typically expands. Your doctor will likely confirm H. pylori has been eradicated, review every medication you take for hidden NSAIDs (including over-the-counter ones), check gastrin levels to rule out a gastrinoma, and perform repeat endoscopy with biopsies to exclude cancer or Crohn’s disease. For skin ulcers, the evaluation may include vascular studies, blood sugar review, and nutritional testing.
Most non-healing ulcers do eventually close once the underlying barrier is identified and removed. The frustrating part is that it sometimes takes more than one round of investigation to find the real culprit, especially when multiple factors overlap, like an H. pylori infection in someone who also smokes and takes ibuprofen for back pain. Addressing all contributing factors simultaneously gives the ulcer its best chance.