Causes of Stomach Ulcers: H. pylori, NSAIDs, and More

Peptic ulcers (gastric or duodenal) result from an imbalance between mucosal defense and damaging forces. Two primary causes dominate:

1. Helicobacter pylori Infection

• Most common cause (~70–90% of duodenal, 50–70% of gastric ulcers).
• Spiral bacterium colonizes gastric mucosa → chronic inflammation → disrupted mucosal defense + increased acid.
• Acquired usually in childhood; persists without treatment.
• Eradication (antibiotics + PPI) cures ulcer and prevents recurrence.

2. NSAIDs (Nonsteroidal Anti-Inflammatory Drugs)

• Aspirin, ibuprofen, naproxen, diclofenac, etc.
• Inhibit COX-1 → reduce prostaglandins → diminish mucus/bicarbonate secretion, blood flow, epithelial repair.
• Risk increases with dose, duration, age, concomitant steroids/anticoagulants, H. pylori co-infection.

Other Contributors

• Alcohol: Direct mucosal irritant; increases acid.
• Corticosteroids: Synergistic with NSAIDs; impair healing.
• Zollinger-Ellison syndrome: Gastrinoma → massive acid hypersecretion.
• Stress (critical illness): "Stress ulcers" from mucosal ischemia in ICU settings.
• Smoking: Impairs healing, increases recurrence.
• Genetics/family history: Modest predisposition.

Prevention & Treatment

H. pylori test-and-treat; NSAID minimization or co-prescription with PPI; lifestyle modification. Most ulcers heal with acid suppression (PPI) + cause removal.