Duodenitis: Inflammation of the First Part of the Small Intestine - Causes, Symptoms, Tests, Treatment and When It Becomes an Emergency
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
TL;DR: Duodenitis is inflammation of the duodenum, the first part of the small intestine. The most common cause is H. pylori infection, followed by overuse of NSAID pain relievers and excess stomach acid. [1] It is usually short-term and clears on its own, but symptoms that last point to chronic duodenitis and need treatment. [1] Left untreated, it can lead to ulcers, dehydration, or iron-deficiency anemia. [1] Blood in vomit or stool needs urgent care.
Seek immediate medical care if you have a fever higher than 102°F (39°C), blood in your vomit (it may look like coffee grounds) or in your stool (it may look dark and tarry), or sudden, severe pain or swelling in your abdomen.
Quick Answer
Duodenitis is inflammation of the duodenum, the first part of the small intestine. It most often starts when H. pylori bacteria, excess stomach acid or NSAID overuse damage the protective lining. [1] Most cases are short-term and improve on their own. When symptoms last, treatment targets the cause with antibiotics, acid-reducing medicines or stopping NSAIDs. [1]
What the research says
H. pylori is very common, though less than it once was. A meta-analysis of 224 studies (2,979,179 people) found global prevalence fell from 58.2% in 1980-90 to 43.1% in 2011-22. An earlier analysis estimated about 4.4 billion infected people in 2015, ranging from 70.1% in Africa to 24.4% in Oceania (Li et al., Lancet Gastroenterol Hepatol, 2023; Hooi et al., Gastroenterology, 2017) [2] [3].
Treating H. pylori helps prevent ulcers from returning. After surgical closure of a perforated duodenal ulcer, the pooled one-year ulcer recurrence rate was 5.2% with H. pylori eradication versus 35.2% without (pooled relative risk 0.15, 95% CI 0.06-0.37) (Tomtitchong et al., Helicobacter, 2012) [4].
Key takeaways
Duodenitis is inflammation of the first part of the small intestine and is similar to gastritis, which affects the stomach. [1]
H. pylori infection is by far the most common cause. Others include NSAID overuse, excess stomach acid, celiac disease [5], Crohn's disease, GERD, and irritating foods or drinks. [1]
It is usually short-term. Lasting symptoms mean chronic duodenitis, which needs treatment. [1]
Untreated, it can lead to peptic duodenitis, duodenal ulcers, dehydration, and iron-deficiency anemia. [1]
Treatment depends on the cause: antibiotics, acid reducers, and lifestyle changes. [1] Blood in vomit or stool needs immediate care.
What Is Duodenitis?
Your duodenum is the first section of the small intestine, closest to the stomach. It has a protective lining that keeps out germs such as bacteria, viruses, and parasites and shields the tissue from the stomach's strong acid. Duodenitis happens when your immune system senses a threat to this lining, such as an infection or damage from stomach juices, and triggers inflammation to fight germs and heal the damage. [1]
Term | Meaning |
Duodenum | The first part of the small intestine, closest to the stomach |
Duodenitis | Inflammation in the duodenum |
Gastritis | Inflammation of the stomach lining (a similar condition) |
Enteritis | Inflammation of the small intestine in general |
For related conditions, see our guides to gastritis and H. pylori infection.
Is Duodenitis Serious?
Usually it is short-term and not serious, and the inflammation goes away on its own. Long-lasting symptoms are a sign of chronic duodenitis. Chronic duodenitis needs treatment from a healthcare provider, which may include one or more medicines. Treating it usually eases the inflammation and prevents complications such as damage to the duodenal lining. [1]
What Are the Symptoms of Duodenitis?
Not everyone has symptoms. When they appear, they may come and go, stay mild, or begin suddenly and severely. [1] A sudden, severe onset is a signal to see a provider.
Symptom | How it feels |
Upper abdominal pain | A gnawing or burning sensation that improves when you eat |
Bloating | A tight, full, or painful feeling in the stomach |
Nausea and vomiting | Feeling sick to your stomach and throwing up; repeated vomiting can cause dehydration |
Diarrhea | Loose, watery bowel movements |
Fatigue | Feeling tired or low in energy |
Gas | Excess air in the digestive tract |
Loss of appetite | Not wanting to eat |
What Are the Signs of Severe Duodenitis?
Bleeding in the digestive tract is sometimes a sign of severe duodenitis. The two warning signs are blood in your vomit, which may look like coffee grounds, and blood in your stool, which may look dark and tarry. [1] Get emergency care right away if you notice either. They may mean duodenitis or another digestive condition that needs treatment.
What Causes Duodenitis?
Duodenitis starts when something threatens the duodenum's protective lining and the immune system responds with inflammation. By far the most common cause is H. pylori infection. [1] This bacterium usually lives in the stomach but can travel to the duodenum. For most people it causes no problems, but if the bacteria multiply out of control they can eat away at the duodenal lining. [1] Older estimates put H. pylori in 50% to 75% of the world's population [1], while newer analyses suggest the figure has fallen (see above). [2]
Cause | How it damages the duodenum |
H. pylori infection | Most common cause; bacterial overgrowth eats away at the lining. |
Other germs | Small intestinal bacterial overgrowth (SIBO) and giardiasis, a parasite infection. |
Overusing NSAIDs | Aspirin, ibuprofen, and naproxen can wear away the duodenal or stomach lining. |
Excess stomach acid | Acid leaks into the duodenum and wears away the lining. |
Celiac disease | An immune response triggered by eating gluten. |
Crohn's disease | An inflammatory bowel disease of the small and large intestines. |
GERD | Chronic acid reflux can trigger inflammation throughout the digestive tract. |
Irritating foods and drinks | Food allergies (including milk and soy) and caffeinated drinks such as coffee and tea. |
Smoking and heavy drinking | Tobacco chemicals irritate the gut, and so does excess alcohol. |
Cancer treatments | Radiation therapy and chemotherapy can inflame the digestive tract. |
To learn more about some of these causes, see our guides to NSAIDs, Crohn's disease, GERD, and SIBO.
Is Duodenitis Contagious?
The inflammation is not contagious, but the H. pylori bacteria that usually cause it are. They spread from person to person through saliva, stool, and contaminated food and water. For example, you can get H. pylori from kissing, or from food prepared by an infected person who did not wash their hands after using the toilet. [1]
What Are the Complications of Untreated Duodenitis?
Complication | What happens |
Peptic duodenitis | Excess stomach acid causes long-term, severe inflammation. Risk factors include H. pylori, NSAID overuse, and smoking. |
Duodenal ulcers | Damage to the lining creates painful open sores, similar to stomach ulcers, that sometimes bleed. |
Dehydration | Vomiting and diarrhea drain body fluid. It is especially dangerous in children and adults age 65 or older. |
Iron-deficiency anemia | Inflammation can block iron absorption, and iron is needed to make red blood cells. |
How Is Duodenitis Diagnosed?
Your provider will ask about your medical history and symptoms. If duodenitis is suspected, tests look for the cause of the inflammation. [1]
Test | What it checks |
Blood test | Can show gluten antibodies, as in celiac disease. Blood antibody tests are not recommended for H. pylori because they cannot tell a past infection from a current one. |
Stool test | Can show an H. pylori infection. |
Breath test | Detects H. pylori by measuring carbon dioxide gas in your breath. |
Upper endoscopy | A scope with a tiny camera shows the esophagus, stomach, and duodenum and can take tissue samples. |
Upper GI series | A series of X-rays of the upper digestive tract that shows how the organs work together. |
What Is the Treatment for Duodenitis?
Duodenitis often improves on its own. If it does not, treatment depends on the cause, and you may need medicines to kill H. pylori or reduce stomach acid, as well as lifestyle changes to protect your gut. [1]
Treatment | Purpose |
Antibiotics | Kill H. pylori bacteria. |
Antacids | Reduce stomach acid. |
Proton pump inhibitors | Reduce stomach acid that damages the duodenal lining. |
Lifestyle changes | Stop NSAIDs if overuse is the cause, avoid gluten if you have celiac disease, eat differently, quit smoking, and cut back on alcohol. |
Surgery to repair severe damage is rarely needed. With an H. pylori infection, antibiotics are usually taken for two weeks. Take all your medicine as prescribed, even if your symptoms improve. [1]
What Foods Should I Eat or Avoid?
Steer clear of foods that can irritate your gut, including spicy foods and highly acidic foods such as citrus or tomato-based dishes. Avoid caffeinated drinks (coffee, tea, soda), and stop or reduce alcohol. Try bland foods until symptoms improve. The BRAT diet (bananas, rice, applesauce, and toast) is a good starting point, and you can gradually add foods with more nutrition, such as chicken soup and broth. Eat a few smaller meals through the day instead of big ones, and try not to eat anything three hours before bedtime. [1]
How Can I Lower My Risk of Duodenitis?
Wash your hands when preparing food, before eating, and after using the toilet. [1]
Do not smoke. If you do, work with your provider on a plan to quit.
Do not drink in excess. The CDC advises no more than two drinks a day for males and one for females. [1]
Do not overuse NSAIDs. Do not take them for more than 3 days for fever or 10 days for pain unless your provider says it is OK. [1]
Avoid gut irritants, including gluten if you have celiac disease and foods you are allergic to.
When Should I Seek Medical Care?
Contact your provider if symptoms have not improved within three or four days, you have vomited for two days straight, you cannot keep liquids down for 24 hours, you have had diarrhea for more than 24 hours, or you have signs of dehydration. Seek immediate care for a fever above 102°F (39°C), blood in your vomit or stool, or sudden, severe abdominal pain or swelling. [1]
Conclusion
Duodenitis is inflammation of the first part of the small intestine, most often triggered by H. pylori, excess stomach acid, or overuse of NSAIDs. In most cases it is brief and resolves without treatment, but symptoms lasting more than three or four days deserve a provider's attention. Treating the cause early prevents peptic duodenitis, ulcers, and other complications.
Related reading
Frequently Asked Questions
What is duodenitis?
Inflammation in the duodenum, the first part of the small intestine, set off when the immune system senses a threat to its protective lining.
How do you pronounce duodenitis?
"DOO-ah-deh-NY-tis."
Is duodenitis the same as gastritis?
No, but they are similar. Gastritis is inflammation of the stomach lining. Duodenitis affects the first part of the small intestine.
How is duodenitis different from enteritis?
Enteritis is inflammation of the small intestine in general. Duodenitis involves only the first part.
Is duodenitis serious?
Usually not. It is typically short-term and goes away on its own. Long-lasting symptoms suggest chronic duodenitis, which needs treatment.
What does duodenitis feel like?
Often a gnawing or burning upper abdominal pain that improves when you eat, with bloating, nausea, vomiting, diarrhea, gas, fatigue, or loss of appetite.
What is the most common cause?
H. pylori infection. Overgrown bacteria can eat away at the duodenal lining.
Can NSAIDs cause duodenitis?
Yes. Overusing aspirin, ibuprofen, or naproxen can wear away the lining of the duodenum or stomach.
Can too much stomach acid cause it?
Yes. Acid that leaks into the duodenum can wear away the lining and trigger inflammation.
Can celiac disease cause duodenitis?
Yes. In celiac disease, eating gluten triggers an immune response that can inflame the duodenum.
Can Crohn's disease, GERD, or cancer treatment cause it?
Yes. Crohn's disease, chronic acid reflux, radiation, and chemotherapy can all inflame the duodenum.
Can coffee, tea, smoking, or alcohol cause it?
Caffeinated drinks, tobacco chemicals, and excess alcohol can irritate the gut and lead to duodenitis.
Is duodenitis contagious?
The inflammation is not, but H. pylori is. It spreads through saliva, stool, and contaminated food or water.
Can you get H. pylori from kissing?
Yes, it can spread through saliva.
Can duodenitis cause ulcers?
Yes. Untreated lining damage can lead to painful open sores called duodenal ulcers, which sometimes bleed.
What is peptic duodenitis?
Long-term, severe duodenal inflammation from excess stomach acid. H. pylori, NSAID overuse, and smoking raise the risk.
Can duodenitis cause anemia?
Yes. Inflammation can block iron absorption, which can lead to iron-deficiency anemia.
How is duodenitis diagnosed?
With blood, stool, or breath tests, an upper endoscopy, or an upper GI series, chosen to find the cause.
How is H. pylori tested for?
With a breath test or a stool test; blood antibody tests are not recommended because they cannot show whether the infection is current.
How is duodenitis treated?
Treatment targets the cause: antibiotics for H. pylori, acid reducers such as antacids and proton pump inhibitors, and lifestyle changes.
How long does treatment take?
With H. pylori, antibiotics are typically taken for two weeks. Finish all the medicine even if you feel better.
What should I eat or avoid?
Choose bland foods and smaller meals, and avoid spicy and acidic foods, caffeine, and alcohol. Do not eat for 3 hours before bed.
How can I prevent duodenitis?
Wash your hands, do not smoke, limit alcohol, avoid overusing NSAIDs, and avoid foods that irritate your gut.
When should I see a doctor?
If symptoms last 3 to 4 days, or you have vomited for 2 days, cannot keep liquids down for 24 hours, or have diarrhea for over 24 hours.
Sources
Cleveland Clinic. Duodenitis. Cleveland Clinic. Last updated May 24, 2024. https://my.clevelandclinic.org/health/diseases/duodenitis
Li Y, Choi H, Leung K, et al. Global prevalence of Helicobacter pylori infection between 1980 and 2022: a systematic review and meta-analysis. Lancet Gastroenterol Hepatol. 2023;8(6):553-564. PMID 37086739. https://doi.org/10.1016/S2468-1253(23)00070-5
Hooi JKY, Lai WY, Ng WK, et al. Global Prevalence of Helicobacter pylori Infection: Systematic Review and Meta-Analysis. Gastroenterology. 2017;153(2):420-429. PMID 28456631. https://doi.org/10.1053/j.gastro.2017.04.022
Tomtitchong P, Siribumrungwong B, Vilaichone RK, et al. Systematic review and meta-analysis: Helicobacter pylori eradication therapy after simple closure of perforated duodenal ulcer. Helicobacter. 2012;17(2):148-152. PMID 22404446. https://doi.org/10.1111/j.1523-5378.2011.00928.x
Owen DR, Owen DA. Celiac Disease and Other Causes of Duodenitis. Arch Pathol Lab Med. 2018;142(1):35-43. PMID 28758791. https://doi.org/10.5858/arpa.2016-0608-RA
Medical disclaimer
The information in this article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have about a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read here. If you think you may have a medical emergency, call your doctor or your local emergency number immediately.
Comments