H. pylori often causes no symptoms. That does not make it benign.

H. pylori is one of the most underdiagnosed conditions I encounter in clinical practice. In my experience performing gastroscopies, up to 30% of patients who come in for an upper GI assessment turn out to have H. pylori, many of them with no symptoms at all, and no idea they were carrying it.

That last part is the problem. The absence of symptoms does not mean the infection is benign. What I often find on gastroscopy in these patients is pronounced inflammation of the stomach lining and duodenum, sometimes with erosions, which is early damage that precedes ulcers. In more severe cases, they may present with severe pain and even bleeding due to ulcers.

Long-term H. pylori infection is associated with chronic inflammation, which over time can progress to intestinal metaplasia, a pre-cancerous state of the stomach lining.

That is what makes H. pylori worth taking seriously, even when you feel fine.

H. pylori is a spiral-shaped bacterium that colonises the stomach lining and the duodenum, the first section of the small intestine. To survive in such an acidic environment, it produces enzymes that neutralise the stomach acid immediately around it, allowing it to persist for years, often decades, without treatment and without causing obvious symptoms.

How common is H. pylori in Singapore? The seroprevalence rate here is 31%, reported by Chew and colleagues in the Singapore Medical Journal in 2017, so close to one person in three is carrying it. Prevalence rises with age in every ethnic group in Singapore, which Kang and colleagues showed in the Journal of Gastroenterology and Hepatology in 1997. It is one of the more prevalent chronic bacterial infections in the local population.

Transmission most often occurs through oral-to-oral contact (shared utensils, close personal contact) or faecal-to-oral routes, in settings with poor sanitation or crowded living conditions. Infections acquired in childhood often persist into adulthood without causing symptoms. Without treatment, H. pylori rarely resolves on its own.

This is the point most health information gets wrong. The majority of people with H. pylori have no symptoms. This is often interpreted as reassurance. It should not be.

On gastroscopy, patients with no symptoms frequently show significant inflammation of the stomach and duodenal lining, and in some cases erosions, which are shallow breaks in the mucosal surface that are precursors to ulcers. This damage is happening silently.

Chronic H. pylori-associated inflammation is a well-established driver of intestinal metaplasia, a condition where the normal stomach lining is gradually replaced by intestinal-type cells. Intestinal metaplasia is a recognised precancerous state and is the change I am most concerned about detecting. It does not cause symptoms. The only way to find it is to look.

This is why I do not treat H. pylori as a condition that only matters when it hurts.

When H. pylori symptoms do appear, they typically arise because the infection has progressed to gastritis or peptic ulcer disease. The most common include:

• A gnawing or burning sensation in the upper abdomen, particularly on an empty stomach
• Persistent bloating or a feeling of fullness after eating only a small amount
• Nausea or vomiting
• Frequent burping
• Loss of appetite
• Unexplained weight loss
• Dark or tarry stools, which may indicate bleeding and warrant urgent medical attention

My approach is as follows. Patients with no symptoms can opt for a breath test. It is accurate, non-invasive, and gives a clear result on active infection. Symptomatic patients should have a gastroscopy, because the test answers more than one question at once: it confirms H. pylori, and it lets me directly assess the severity of inflammation, check for erosions or ulcers, and look for intestinal metaplasia.

Beyond symptomatic patients, testing is also appropriate for:

• Individuals with a personal or family history of gastric cancer
• Those with close, prolonged contact with a confirmed H. pylori carrier
• Patients on long-term NSAIDs or aspirin, which increase the risk of ulcer complications in the presence of H. pylori
• Anyone over 45 who has never been tested, given the rise in prevalence with age

H. pylori testing addresses the upper GI tract specifically. Patients who also present with lower abdominal pain or changes in bowel habits should discuss the full symptom picture with a specialist, as these may point to separate or co-existing conditions.

There are several ways to test for H. pylori. The right method depends on your symptoms, medical history, and whether a broader upper GI assessment is clinically indicated.

Treatment involves a combination of a proton pump inhibitor (to reduce stomach acid and support healing) and two antibiotics, taken over two weeks. That fortnight is not arbitrary. The Singapore standard used to be one week, and Ang and colleagues set out in Gut and Liver in 2021 why it was lengthened: antibiotic resistance had crept up far enough that the shorter course no longer cleared the infection reliably. The course must be completed in full; stopping early may increase the risk of the infection returning and of antibiotic resistance developing.

It works, and the honest answer is a published number a reader can check, not an assurance. Pei and colleagues reported in the Journal of Digestive Diseases in 2022 that two-week first-line therapy cleared the infection in 91.7% of patients treated in Singapore in 2019 and 2020, 891 of 972. The same study is the reason the regimen still holds here at all: clarithromycin resistance locally sat at 13.7%, under the 15% threshold above which the regimen would have to change.

Once treatment is finished, a follow-up test is arranged to confirm eradication. This is performed at least four weeks after completing antibiotic treatment, using either a urea breath test or a stool antigen test. Eradication confirmation is a required clinical step, and the 91.7% above is exactly why: roughly one course in twelve does not work, and testing is the only way to know whether yours was the one.

Where first-line treatment does not succeed, second-line regimens are available. I will advise on the next step based on your clinical picture and, where relevant, local antibiotic resistance patterns.