Enteritis is inflammation of your small intestine. It may also include your stomach (gastroenteritis) or colon (enterocolitis). It’s usually caused by a viral, bacterial or parasitic infection (food poisoning, stomach bug or the stomach flu). Sometimes it’s caused by radiation, drugs or disease.
Enteritis is inflammation of your small intestine. The most common causes are viral and bacterial infections. Enteritis can also include your stomach (gastroenteritis) or your large intestine (enterocolitis). Enteritis caused by infection is often gastroenteritis. Common examples are food poisoning and the stomach flu.
When your small intestine is irritated and inflamed, it may cause fever, swelling and abdominal pain. This may affect your digestive process, resulting in nausea, diarrhea and vomiting. Acute enteritis comes on suddenly and usually only lasts a few days. Less commonly, a chronic condition may cause persistent enteritis.
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Most of the time, enteritis is brief and you can manage it well at home. The biggest risk is dehydration caused by diarrhea and vomiting and an inability to keep fluids down. If you are taking care to rest and replenish your fluids with electrolyte formulas and liquids, you should feel better soon.
If you have a bacterial infection, you may need antibiotics to treat it or, in rare cases, hospitalization to treat dehydration. If enteritis lasts a long time, it could cause more serious complications, but this is rare.
There are four broad categories of enteritis. Each has its own common cause.
Infectious enteritis — the most common type — is caused by viruses, bacteria or even parasites. Viruses, bacteria and parasites are highly contagious. They spread through contaminated food or water or through contact with another person who is infected.
Viruses that commonly cause enteritis include:
Bacteria that commonly cause enteritis include:
Parasites that commonly cause enteritis include:
Primary inflammatory enteritis is caused by certain autoimmune diseases that affect the digestive system. Autoimmune diseases can mistake food in your digestive tract for infectious agents, causing an inflammatory response. This can be a chronic problem. Diseases include:
In addition to diseases, overuse of certain drugs can inflame your intestines. These include:
Radiation enteritis, also called secondary inflammatory enteritis, is caused by radiation exposure, particularly to the abdominal and pelvic areas. Radiation therapy and chemotherapy are used to kill cancer cells, but they can also kill healthy cells in the protective lining of your mouth, stomach and intestines. This destroys the protective lining, leading to irritation and inflammation.
For most people, radiation enteritis lasts only a few weeks after treatment. But occasionally, in some people, it persists for months or even years. Scientists don’t know why this occurs. People with chronic radiation enteritis may be at risk of serious damage to their small intestine.
Intestinal ischemic syndrome occurs when the blood supply to a portion of your intestines is blocked. Small intestine ischemia, while uncommon, can be a serious illness. It can result in enteritis and all of its typical symptoms.
Symptoms of enteritis are consistent regardless of the type of enteritis you have. Symptoms include:
The most serious complication of acute enteritis is dehydration. Dehydration can be mild or severe. While healthy adults can bounce back relatively easily from dehydration, it's a more dangerous risk for children, people who are elderly and those who are immunocompromised. Severe dehydration can have serious consequences. If you have enteritis or are looking after a loved one with enteritis, make sure you or they are replacing fluids after diarrhea or vomiting. Stay alert to the signs of dehydration. Signs include:
Although less common, chronic enteritis resulting from radiation therapy or inflammatory bowel disease can have serious long-term side effects, including:
Enteritis is usually diagnosed based on your symptoms, medical history and a physical exam. In some cases, your healthcare provider may want to conduct tests to find out the cause of your enteritis. For example, they may analyze a sample of your poop in a lab to identify the type of infection you have. If they aren’t sure of the cause or need more information, they may want to do X-rays or other images of your small intestine. An upper endoscopy exam can take images and tissue samples at the same time. The tissue samples can then be analyzed to find out more about what’s going on in your small intestine.
Treatment for enteritis is focused on managing symptoms. Rest and rehydration are usually enough. If the cause is infection, your body will usually fight it without help. Occasionally, a bacterial infection may last longer than usual, and your healthcare provider may prescribe antibiotics to help fight it. If the cause is radiation, your healthcare provider will discontinue your radiation therapy either temporarily or permanently. If the cause is ischemia or autoimmune disease, these conditions must be treated directly. Your healthcare provider may prescribe anti-inflammatory medication for chronic enteritis.
It usually does. Infectious enteritis should clear up within a week. Radiation enteritis should clear up within a few weeks. If you have a chronic condition that causes recurring enteritis, it may come and go. Long-lasting enteritis is rare but serious. Contact your healthcare provider if your symptoms go on longer than they should.
Infectious enteritis, the most common kind, is also the most preventable. If you’ve had your share of stomach bugs for one lifetime, then you can help prevent getting it and spreading it to others with safe hygiene practices.
If you’re having trouble keeping food down, it helps to keep it simple and bland. Healthcare providers still recommend the BRAT diet for easing slowly back into eating — that’s bananas, rice, applesauce and toast. It’s not great nutrition for the long term, but it will do for a few days. Eat small amounts frequently to prevent nausea.
Chicken soup with saltine crackers is another good standby for when you’re starting to feel better. If you’re not ready for solid food yet, plain broths can help a lot to keep you hydrated and give you a little energy boost in the meantime. Being sick is hard work, after all.
If you’re tending enteritis at home, it should start to improve in a few days. But contact your healthcare provider if:
A note from Cleveland Clinic
“Stomach flu.” “Stomach bug.” “Food poisoning.” If you’ve experienced any of these, you know all about enteritis. Not to be confused with influenza— which isn’t actually an intestinal infection but a respiratory one — the “stomach flu” is a familiar seasonal visitor that spreads just as easily from person to person as that other flu. But you may not know that you can also get enteritis from overuse of alcohol, aspirin or ibuprofen, or secondary to another condition. Regardless of the cause, enteritis is no fun, but it usually passes shortly on its own. If you're in the trenches, rest well, stay hydrated, and contact your healthcare provider if your symptoms last longer than a few days.
Last reviewed by a Cleveland Clinic medical professional on 05/14/2022.
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