Gastritis

'Gastritis' means inflammation of the stomach lining. It is a common symptom with a wide range of causes.

The stomach lining ('mucosa') contains special cells that produce acid and enzymes that start to digest food.

The acid can potentially break down the stomach lining too, so other cells in the lining produce mucus to provide a slimy layer that protects it from this acid.

Gastritis happens when this defence barrier is damaged – by H. pylori bacteria or after excessive consumption of alcohol, for example (see What are the possible causes?).

For most people, gastritis isn't serious and improves quickly with treatment. But if it is left untreated, it can last for years.

What are the symptoms of gastritis?

Many people with gastritis don't have any symptoms – usually because they have a non-erosive form of the disease caused by a bacterial infection (see What are the possible causes?). 

In other cases, gastritis can cause:

• gnawing or burning stomach pain
• nausea and vomiting
• feeling full after eating

If the stomach lining has been worn away, it is classed as erosive gastritis. Damaged areas of stomach lining (unprotected by mucus) are exposed to stomach acid, which can cause pain and lead to stomach ulcers and bleeding.

If symptoms come on suddenly and severely, it is classed as acute gastritis. If it has lasted a long time (usually because of bacterial infection), it is chronic gastritis.

What are the possible causes of gastritis?

Gastritis is usually caused by one of the following:

• An infection: almost always a Helicobacter pylori bacterial infection (see below), but occasionally viruses, parasites, fungi, and bacteria other than H. pylori are the culprits
• Excessive use of cocaine or alcohol
• Regularly taking aspirin, ibuprofen or other painkillers classed as non-steroidal anti-inflammatory drugs (NSAIDs) 
• A stressful event – such as a bad injury or critical illness, or major surgery. Exactly why stress and serious illness can lead to gastritis is not known, but it may be related to decreased blood flow to the stomach.

Less commonly, gastritis can be caused by an autoimmune reaction – when the immune system mistakenly attacks the body's own cells and tissues (in this case, the stomach lining). This may happen if you already have another autoimmune condition, such as Hashimoto's thyroid disease or type 1 diabetes.

H. pylori gastritis

Many people become infected with H. pylori bacteria and don't realise it. These stomach infections are common and usually don't cause symptoms.

Sometimes, though, an H. pylori infection can cause recurring bouts of indigestion. The bacteria can cause inflammation of the stomach lining.

This sort of gastritis is more common in older age groups and is usually the cause of chronic (persistent) non-erosive cases.

An H. pylori stomach infection is usually lifelong, unless it is treated with H. pylori eradication therapy (see below).

What should I do?

If you have indigestion and stomach pain, you can try treating this yourself with changes to your diet and lifestyle, or with a number of different over-the-counter medications, such as antacids.

See your GP if:

• you have indigestion symptoms lasting a week or longer, or it is causing you severe pain or discomfort
• it comes on after taking prescription or over-the-counter drugs (such as aspirin)
• you are vomiting blood or have blood in your stools (your stools may appear black)

How is gastritis diagnosed?

To identify the underlying cause, your GP may recommend you have one or more of the following tests:

• A blood test to check for H. pylori infection and to check for anaemia (which may indicate bleeding from the stomach).
• A stool test – to check for H. pylori infection and to check for blood in the poo (which may indicate bleeding from the stomach).
• A breath test for H. pylori infection – which involves drinking a glass of clear, tasteless liquid that contains radioactive carbon and later blowing into a bag, which is then sealed. H. pylori would break down the liquid in your stomach so that your breath sample contained radioactive carbon.
• An endoscopy to examine your digestive system – a flexible tube (endoscope) is passed down your throat and into your oesophagus and stomach to look for signs of inflammation. A small sample (biopsy) of your stomach may be taken using an instrument attached to the endoscope. This can be performed with or without sedation.
• A barium swallow and X-ray – this is an alternative way to look for changes (such as ulcers) in the stomach lining. It is not as accurate as an endoscopy.

How is gastritis treated?

Treatment aims to reduce the amount of acid in the stomach to relieve symptoms and allow the stomach lining to heal, and to tackle any underlying cause.

You may be able to treat gastritis yourself, depending on the cause.

Easing symptoms

• antacids – these over-the-counter medicines neutralise the acid in your stomach, which can provide rapid pain relief
• histamine 2 (H2) blockers such as ranitidine – these medicines decrease acid production, and are available both over the counter and on prescription
• proton pump inhibitors (PPIs) such as omeprazole – these medicines decrease acid production even more effectively than H2 blockers, and are available both over the counter and on prescription

Treating H. pylori infection

If you've been diagnosed with an H. pylori infection, you'll need H. pylori eradication therapy – which is essentially taking a proton pump inhibitor and two antibiotics. Learn more about eradication therapy.

What else can I do to help myself?

If you think the cause of your gastritis is repeated use of NSAID painkillers, try switching to a different painkiller that isn't in the NSAID class, such as paracetamol. You may want to talk to your GP about this.

Also, consider:

• eating smaller, more frequent meals
• avoiding irritating (spicy, acidic or fried) foods 
• avoiding or cutting down on alcohol
• managing stress (read our relaxation tips) 

What are the possible complications of gastritis?

Ongoing (chronic) gastritis increases your risk of developing:

• a stomach ulcer
• polyps (small growths) in your stomach
• tumours in your stomach, which may or may not be cancerous