h. pylori

H Pylori Infections: Symptoms, Diagnosis, and Treatment

Helicobacter pylori (H. pylori) infections are very common worldwide. They infect over half of the world’s population. The condition is often undiagnosed because it does not cause symptoms in most cases. However, it can lead to complications, including stomach cancer.

In this article, we’ll explore H. pylori infections including symptoms, diagnostics, and treatment.

h. pylori - woman clutching stomach in pain

H. Pylori Symptoms

H. pylori infect the stomach and cause digestive symptoms. Symptoms include:

  • Upset stomach
  • Indigestion
  • Nausea
  • Lack of appetite
  • Acid reflux
  • Excessive gas and bloating
  • Diarrhea
  • Constipation

Some people lose weight, while others may gain weight with the infection.

Many people also experience unusual bad breath despite proper oral hygiene. Bad breath can also be a telltale sign of reinfection for some.

h. pylori - surgical room with doctors with scrubs

What Will Happen if H. Pylori Goes Untreated?

For children with an H. pylori infection, they have the ability to clear it naturally. However, adults need treatment to eradicate it.

If left untreated, H. pylori can cause gastritis, peptic ulcers, and stomach cancer. Certain symptoms can suggest when these complications develop, in some cases.


In the case of gastritis, one may feel a gnawing or burning pain in the stomach, which becomes worse after meals. They may also have a feeling of fullness in the upper part of the abdomen with meals. Nausea and vomiting are also symptoms of gastritis.

However, in some cases, gastritis may not cause any symptoms.

Peptic Ulcers

Peptic ulcers cause dull pain in the stomach, excessive gas with burping and bloating, and acid reflux. Ulcers can further complicate and bleed, perforate, or penetrate into other organs. They can also cause obstructions.

Stomach Cancer

According to the World Health Organization (WHO), H. pylori bacterium is a strong risk factor for some forms of stomach cancer. They consider this bacterium a class I carcinogen.

According to 2018 data, infections cause about 13% of all cancers in the US. H. Pylori is the number one cancer-causing microbe and is responsible for over 800,000 stomach cancer cases during that year.

With who have an H. pylori infection are three to six times more likely to develop stomach cancer. About 3-5% of H. pylori infections left untreated can lead to cancer. However, specific strains of the bacteria are more likely involved.

During the early stages of stomach cancer, there may be no symptoms. As it develops, symptoms get worse over time. Some symptoms of stomach cancer include:

  • Persistent stomach pain
  • Heartburn
  • Indigestion
  • Bloating
  • Bloody or black stools
  • Swallowing problems
  • Unintentional weight loss
  • Anemia

Other Complications

H. pylori infections may also cause food intolerances. There may be a link between these intolerances and conditions like irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), and fibromyalgia.

h. pylori - nurse administering blood test on patient's arm

Diagnostic Tests for H. Pylori

Tests are important to detect an infection in the beginning. Doctors also test patients after treatment to confirm the eradication of the bacteria.

There are four main types of tests: breath, blood, stool antigen, and endoscopy. The breath test is highly accurate and can assess active infections. The stool antigen test is the second most accurate to detect infection. However, both tests may lead to false-negative results.

The blood tests cannot detect active infection. But it can help confirm if treatment was successful in eradicating the bacteria. Endoscopy is also useful to diagnose infection and confirm treatment success. However, it is invasive and requires sedation.

It is best to take a test before starting an antibiotic because the medication can interfere with results. Be sure to stop proton pump inhibitors (PPIs) one to two weeks before the test.

h. pylori - medications

How to Treat H. Pylori

This bacterium is very resilient. It has protective mechanisms to survive harsh environments, such as stomach acid. At times, it can be difficult to eliminate.

Treatment involves a combination of two or three antibiotics and a proton pump inhibitor (PPI) or another acid blocker. Doctors may also add Pepto Bismol to make the treatment more effective.

An example of a treatment protocol is amoxicillin and clarithromycin (antibiotics) plus omeprazole (PPI) for 10 to 14 days.

A newer form of treatment is a two-step, 10-day program. It uses different antibiotics in the first and second parts of the therapy. For example, doctors prescribe amoxicillin plus a PPI during the first five days. Then they will prescribe clarithromycin, metronidazole, and a PPI for the last five days.

Doctors recommend retesting after four weeks of treatment. If the infection is still present, they will administer a second round of treatment. This treatment will have a different drug combination.

It’s a good idea to retest for H. pylori infection every few years because re-infections do occur. If you experience frequent infections, you can use supplements or a diet to manage them as well.