Gastritis is an inflammation of the stomach lining. The lining of the stomach often looks red, irritated and swollen, and it may have raw areas that can bleed.

Many different illnesses and irritants — acting either alone or in combination — can trigger the inflammation of gastritis. Some of the most common triggers include:

•  Infection with Helicobacter pylori (H. pylori) bacteria — In addition to causing gastritis, H. pylori infections have been linked to the development of stomach cancer and peptic ulcer disease, open sores inside the stomach or part of the small intestine. Although doctors are not sure how people become infected with H. pylori, they suspect the bacteria are spread through contaminated food, water, saliva or digestive fluids. In the United States, the number of people infected with H. pylori increases with age. About 20% of Americans under age 40 have the bacteria, while it infects about 50% of people over age 60. Many people infected with H. pylori never complain of digestive symptoms. Doctors don't understand why people respond differently.
• Viral infections — Brief bouts of gastritis are common during short-term viral infections.
• Irritants — Chemical and environmental irritants can damage the stomach lining and cause gastritis. Common irritants include alcohol; cigarette smoke; corticosteroids and certain other prescription medications; and aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin and others) and naproxen (Aleve, Naprosyn and others).

In the United States, gastritis accounts for approximately 2 million visits to doctors' offices each year. Although gastritis can occur in people of all ages and backgrounds, it is especially common in:

• People over age 60
• People who drink too much alcohol
• Smokers
• People who take corticosteroids or other prescription medications that can cause gastritis
•  People who routinely use aspirin or NSAIDs, especially at high doses

Symptoms

Symptoms of gastritis can include:

• Abdominal discomfort that may become worse after eating
• Persistent pain between the navel and lower ribs
• Nausea, sometimes with vomiting
• Poor appetite
• Belching, bloating or a feeling of fullness in the abdomen
• With severe gastritis, sometimes bloody vomiting and black stools

Diagnosis

After reviewing your symptoms, the doctor will ask you about your lifestyle. Specifically, the doctor will want to know:

• The amount of alcohol you drink
• Medications you are taking, in particular corticosteroids, aspirin or NSAIDs
• Whether you have tried over-the-counter antacids or other medicines to treat your symptoms and whether these helped

Your doctor will examine you, paying special attention to your abdomen. He or she may do a digital rectal examination to obtain a small smear of feces or rectal fluids to be checked for the presence of blood. Based on your medical history, symptoms and physical examination, your doctor will decide if you should try medical treatment first to see if symptoms improve or if you need further testing. You may need blood tests or a breath test to determine whether you have an H. pylori infection. In some cases, your doctor may want to inspect your stomach lining directly with a procedure called gastroscopy, in which a flexible, lighted instrument is passed into your stomach. During the procedure, your doctor can take a biopsy, a small tissue sample to be examined in the laboratory.

Gastroscopy also is done if:

• The results of your initial physical exam or rectal exam are not normal.
• You have seen blood in your vomit or stool.
• Your rectal smear tests positive for blood.
•  You have unusual symptoms, such as weight loss or extreme fatigue.

Expected Duration

If you have mild, uncomplicated gastritis, your symptoms probably will improve after only a few days of treatment.

Prevention

To help prevent gastritis:

• Don't smoke.
• If you drink alcohol, do so in moderation. Most experts recommend that women limit alcohol use to no more than one drink a day and that men have no more than two drinks a day.
• If you take an NSAID to treat a medical problem, and the medicine upsets your stomach, stop taking the medicine and speak with your doctor.

Treatment

If you have mild, uncomplicated gastritis, you may need to:

• Stop smoking
• Stop drinking alcohol temporarily. After gastritis heals, your doctor will advise you to consume no more than one to two drinks a day, or none at all
• Avoid foods that you think may make your symptoms worse. Foods that cause problems most often include foods that are fatty, spicy or very acidic (coffee, orange juice, tomato juice).
• Use medications to decrease stomach acids. You may try over-the-counter antacids (such as Maalox, Mylanta, Tums or generic forms) or an H2 blocker (Tagamet, Zantac, Pepcid and generic equivalents). H2 blockers also are available in prescription strength. Proton pump inhibitors such as omeprazole (Prilosec) and lansoprazole (Prevacid) are the strongest acid blockers, but are usually more expensive.

This approach should help you begin to feel better within a few days, with maximum results after a week or two.

If you still have symptoms, and further testing confirms that you have an H. pylori infection, your doctor will treat you with medications to kill the bacteria. If symptoms still continue, the doctor will recommend gastroscopy or X-rays to outline the upper portion of your digestive tract, including the stomach (a process called an upper GI series).