Gastritis is inflammation of the stomach lining, the protective mucous barrier that shields the stomach wall from the acid and digestive enzymes it produces to break down food. Gastritis is extremely common and, in most cases, resolves quickly and completely with appropriate treatment. In a meaningful proportion of cases, however, gastritis becomes a long-standing, chronic condition — and understanding this distinction matters, because chronic gastritis is not simply a more persistent version of the same mild problem. Left unaddressed over years, certain forms of chronic gastritis can gradually change the stomach lining in ways that meaningfully raise the long-term risk of gastric cancer.
This is a particularly relevant point in Singapore and the wider region, where infection with Helicobacter pylori — the bacterium responsible for the majority of chronic gastritis cases worldwide — remains more common than in many Western countries, and where gastric cancer risk is correspondingly higher in certain populations. The reassuring counterpart is that gastritis, including H. pylori infection, is very treatable, and treating it properly does more than relieve symptoms — it can meaningfully reduce a person's long-term cancer risk.
How the Stomach Lining Protects Itself
The stomach produces powerful acid and digestive enzymes strong enough to break down food — and strong enough to damage the stomach's own tissue if left unchecked. To prevent this, the stomach lining maintains a protective mucus-and-bicarbonate barrier, supported by prostaglandins (natural compounds that help maintain blood flow and mucus production), that shields the underlying tissue from this acidic environment.
Gastritis develops when this protective barrier is overwhelmed or weakened — whether by infection, medication, alcohol, or the body's own immune system — allowing stomach acid and enzymes to irritate and inflame the tissue underneath. Depending on the cause and how long it persists, this inflammation can range from a mild, short-lived irritation to a chronic process that gradually and permanently changes the structure of the stomach lining.
Acute vs. Chronic Gastritis
- Acute Gastritis: A sudden onset of inflammation, often triggered by a specific event such as heavy alcohol use, NSAID use, acute stress (including severe illness or major surgery), or a new infection. Symptoms tend to appear abruptly and typically resolve relatively quickly once the trigger is removed and appropriate treatment is given.
- Chronic Gastritis: Inflammation that develops and persists gradually over months to years, most commonly due to ongoing H. pylori infection or, less commonly, an autoimmune process. Often causes milder or even absent day-to-day symptoms, which is precisely what makes it easy to overlook — despite carrying the more significant long-term implications for stomach health.
Causes of Gastritis
- Helicobacter pylori Infection: The most common cause of chronic gastritis worldwide. This bacterium colonises the stomach lining and triggers ongoing inflammation, often acquired in childhood and, if untreated, persisting for decades. A recognised cause of peptic ulcers and a major risk factor for gastric cancer.
- NSAID Use: Regular use of non-steroidal anti-inflammatory drugs (such as ibuprofen or aspirin) reduces the stomach's protective prostaglandin production, directly weakening the mucosal barrier. A common cause of both acute and chronic gastritis, particularly with frequent or long-term use.
- Alcohol: Directly irritates and erodes the stomach lining, particularly with heavy or frequent consumption.
- Autoimmune Gastritis: A less common but important cause, in which the immune system mistakenly attacks the cells of the stomach lining responsible for acid and intrinsic factor production. Leads to reduced stomach acid and can cause vitamin B12 deficiency, since intrinsic factor is required for B12 absorption.
- Stress-Related Gastritis: Can develop in the context of severe physical stress, such as critical illness, major trauma, or major surgery, due to reduced blood flow to the stomach lining during periods of severe physiological stress.
- Bile Reflux: Backflow of bile from the small intestine into the stomach can irritate and inflame the stomach lining over time.
Why Chronic Gastritis Deserves Long-Term Attention
Chronic gastritis, particularly when caused by long-standing H. pylori infection, follows a well-documented, gradual progression that researchers call the Correa cascade — named after the pathologist who first described it. Understanding this progression is the key to understanding why chronic gastritis is treated as more than a persistent nuisance.
The pathway moves through recognisable stages: chronic inflammation (gastritis) can lead to atrophic gastritis, in which the stomach lining's normal glands are gradually lost; this can progress to intestinal metaplasia, where the stomach lining is replaced by tissue that more closely resembles the lining of the intestine; and, in a smaller subset of cases, this can eventually progress further to dysplasia and, ultimately, gastric cancer. Not everyone with chronic gastritis progresses along this entire pathway — the large majority do not — but the risk is real enough, particularly in populations with higher rates of H. pylori infection, that it shapes how chronic gastritis is managed.
There is a genuinely encouraging side to this: eradicating H. pylori infection, particularly earlier in this progression, can halt further progression and, in some cases, allow the stomach lining to partially recover. This is why H. pylori testing and treatment is recommended even for people with mild or no symptoms, and why patients found to have more advanced changes, such as intestinal metaplasia, are typically recommended periodic surveillance endoscopy — to catch any further progression at the earliest, most treatable point.
Symptoms of Gastritis
Gastritis, particularly the chronic form, may cause no noticeable symptoms at all. When symptoms do occur, they include:
- Burning pain in the upper abdomen
- Indigestion or a feeling of fullness after eating
- Loss of appetite
- Nausea, with or without vomiting
- Bloating
Symptoms suggesting a more serious complication, such as bleeding or a peptic ulcer, include:
- Black or tarry stools, or visible blood in vomit
- Unexplained fatigue or symptoms of anaemia (which can result from slow, ongoing blood loss or, in autoimmune gastritis, impaired B12 absorption)
- Persistent vomiting
- Unintentional weight loss
Risk Factors for Gastritis
- H. pylori infection — the single most common underlying cause of chronic gastritis worldwide
- Regular use of NSAIDs or other pain relievers
- Excessive alcohol use
- Older age — the stomach lining naturally thins with age, increasing susceptibility
- Chronic stress, including from severe illness or major surgery
- Other medical conditions, including Crohn's disease, coeliac disease, HIV/AIDS, and certain parasitic infections
- Smoking, which impairs the stomach lining's ability to heal and repair itself
- Family history of gastric cancer or pernicious anaemia, relevant to autoimmune gastritis risk
How Gastritis is Diagnosed
- Endoscopy with Biopsy: The most definitive test. A thin camera examines the oesophagus, stomach, and upper small intestine directly, and tissue samples are taken to confirm inflammation, test for H. pylori, and assess for atrophic changes or intestinal metaplasia — information that cannot be obtained any other way.
- Urea Breath Test: A non-invasive test for active H. pylori infection. A special drink is taken, and breath samples are analysed for a by-product that only appears if H. pylori bacteria are present and metabolising the substance.
- Stool Antigen Test: Detects H. pylori proteins in a stool sample, another non-invasive option for both initial diagnosis and confirming successful eradication after treatment.
- Blood Tests: Can check for anaemia (relevant to bleeding or B12 deficiency), and specific antibody testing can support a diagnosis of autoimmune gastritis or, less commonly, past H. pylori exposure.
Reducing Your Risk of Gsstritis
- Practise good hand hygiene, which reduces the risk of acquiring H. pylori infection
- Use NSAIDs sparingly, and discuss alternatives or protective co-treatment with your doctor if you need to take them regularly
- Limit alcohol consumption
- Avoid smoking
- Manage stress through practical, sustainable strategies, since chronic stress can contribute to gastritis
- If you have a family history of gastric cancer or persistent digestive symptoms, ask your doctor whether H. pylori testing is appropriate, even without significant symptoms
