Most people infected with H. pylori have no symptoms at all. The bacterium can live in the stomach lining for years without causing noticeable problems. When symptoms do appear, they typically center on a burning or aching pain in the upper abdomen that feels worse on an empty stomach.
The Most Common Symptoms
The hallmark symptom is a dull or burning pain in the stomach area, usually in the upper middle section just below the ribs. This pain tends to flare up a few hours after eating and at night, when the stomach is empty. It can last anywhere from a few minutes to several hours and often comes and goes over days or weeks, making it easy to dismiss as ordinary indigestion.
Beyond stomach pain, other common symptoms include:
- Bloating and frequent burping
- Nausea, sometimes with vomiting
- Loss of appetite or feeling full after eating only a small amount
- Unexplained weight loss
- Indigestion that doesn’t respond to the usual remedies
These symptoms overlap heavily with other digestive conditions, which is why H. pylori often goes undiagnosed for a long time. The pattern to watch for is recurring upper stomach pain that improves briefly after eating, then returns once the stomach empties again.
Why the Infection Causes Pain
H. pylori survives in the stomach by producing an enzyme that neutralizes acid in its immediate surroundings, creating a small safe zone. But this process generates ammonia as a byproduct, which is toxic to the cells lining your stomach. At the same time, the bacterium releases substances that break down the protective mucus layer coating the stomach wall. Once that barrier thins out, stomach acid can reach the delicate tissue underneath and cause irritation or open sores.
The bacterium also attaches directly to stomach lining cells and damages them, triggering inflammation. Over time, this chronic inflammation (gastritis) can progress to peptic ulcers, which are small craters in the stomach or upper intestinal lining. Ulcers intensify the burning pain and can lead to more serious complications.
Symptoms That Need Urgent Attention
Most H. pylori symptoms are uncomfortable but not dangerous. However, if the infection leads to a bleeding ulcer, the signs change quickly. Vomiting blood, or vomit that looks like dark coffee grounds, signals active bleeding in the stomach. Black, tarry stools are another warning sign, indicating blood has passed through the digestive tract. Severe, sudden stomach pain that doesn’t let up can mean an ulcer has perforated the stomach wall. Any of these requires emergency care.
Symptoms in Children
H. pylori infection is generally silent in children. Only about 5% to 10% of infected kids develop noticeable symptoms, and when they do, the picture looks different from adults. Research has found that only upper abdominal pain has a statistically significant link to H. pylori in children. Other digestive complaints like vomiting, diarrhea, constipation, and general abdominal pain don’t appear to be caused by the infection itself, even though they’re common in kids who happen to test positive.
Children with H. pylori also develop ulcers at lower rates than adults. One concern specific to younger patients, though, is growth. A meta-analysis of 29 studies found that H. pylori infection is linked to growth deficits in children, particularly reduced height-for-age scores, possibly because the chronic stomach inflammation interferes with nutrient absorption during critical developmental years.
The Link to Iron Deficiency
H. pylori can cause problems that extend beyond the stomach. One of the most well-documented is iron deficiency anemia, especially in children and adolescents. Up to one-fourth of children with H. pylori infection develop iron deficiency or iron deficiency anemia. If you or your child has unexplained low iron that doesn’t improve with supplements, H. pylori may be the underlying cause.
The bacterium appears to interfere with iron absorption in multiple ways. Chronic inflammation in the stomach lining reduces acid production, and stomach acid is essential for absorbing iron from food. The bacterium also competes directly with the body for available iron in the upper digestive tract. Studies have shown that eradicating H. pylori alongside iron supplementation raises hemoglobin, serum iron, and ferritin levels significantly more than iron supplements alone. In other words, the supplements work better once the infection is gone.
How H. Pylori Is Detected
Because the symptoms are so nonspecific, testing is the only way to confirm an H. pylori infection. The most common noninvasive option is the urea breath test: you drink a solution containing a special form of carbon, and if H. pylori is present, the bacterium breaks it down in a way that’s detectable in your breath about 15 minutes later. A large meta-analysis found this test is roughly 88% sensitive and 85% specific, meaning it catches most infections and rarely gives false positives.
A stool antigen test works similarly well and is often used for children or for confirming that treatment has cleared the infection. In cases where symptoms are more severe, or when a doctor suspects an ulcer or other complication, an endoscopy allows direct visualization of the stomach lining and a tissue sample for testing. Most people start with one of the noninvasive options first.