Causes of Abdominal Bloating

Bloating is a common symptom that can have a variety of causes—from simply swallowing too much air to serious conditions like infection and cancer. Sometimes, people report feeling so bloated they think they look pregnant!

It can present as a feeling of indigestion or a tight abdomen, but some people can visually see that their belly is distended or their clothes feel too tight around the middle. If your bloating is persistent or getting worse, you should see a healthcare provider.

This article outlines conditions that can cause abdominal bloating, from food intolerance to cancer, when to talk to a healthcare provider about your symptoms, and the tests they'll use to reach a diagnosis.

What Is Abdominal Bloating?

Bloating is a common feeling with many potential causes. It results in an uncomfortable sensation of fullness or tightness that can visually enlarge the stomach and cause clothing to feel too small. Up to 30% of the population reports feeling bloated at some point.

Dietary habits, specific food intolerances, or underlying medical issues ranging from infection to cancer—though those are less common—can contribute to bloating. Diagnosing the reasons for bloating is key to managing it.

What Causes Abdominal Bloating?

The reasons your abdomen might be bloated vary widely, from simple reasons to more serious ones. Several of the reasons for bloating relate to food, while others have to do with infection or even cancer.

Food

Food is one of the most common reasons for bloating. Diet, food intolerance, and eating habits are all factors that can increase the risk of bloating.

• Diet: Several types of foods can cause some people to have excessive gas. Fatty foods and a variety of healthy foods such as cruciferous vegetables (broccoli and Brussels sprouts), beans, some fruits (apples and oranges), dairy products, alcohol, and carbonated beverages can all be culprits.

• Food Intolerances: Abdominal bloating is a hallmark symptom of gluten intolerance, lactose intolerance, and celiac disease, an autoimmune disorder where gluten (a protein found in wheat, barley, and rye) triggers an immune response that affects the small intestines.
  
• Eating Habits: Overeating can cause you to feel bloated; some foods are much more likely to do this than others. Eating too much can cause bloating or expansion of the stomach. Swallowing air from eating too quickly or chewing gum can also cause bloating.

Infections

Several infections can cause bloating or fullness in the abdominal area.

• Appendicitis: An infection of the appendix, appendicitis can cause severe pain, fever, inflammation, and sometimes bloating. Appendicitis is a serious condition that may cause the appendix to rupture. These complications are life-threatening, and urgent treatment often includes surgery.
  
• E. coli infection: Escherichia coli (E. coli) is a type of bacteria that may be transmitted through contaminated food or unhygienic practices in food preparation and handwashing. This infection can cause abdominal pain, diarrhea, vomiting, and bloating.
• H. Pylori infection: Helicobacter pylori (H. pylori) is a bacterial infection that doesn't usually cause symptoms, but it can cause stomach ulcers and, less often, contribute to the development of stomach cancer.
• Peritonitis: The peritoneum is the lining around the abdominal organs. It can become inflamed or infected, leading to peritonitis. Symptoms can include pain, nausea, vomiting, abdominal swelling, and constipation.
• Urinary tract infection (UTI): A UTI typically causes urinary frequency and urgency, often with a sensation of burning during urination. Sometimes, the abdomen may feel bloated or swollen as well.
• Viral gastroenteritis: Viral gastroenteritis ("the stomach flu") is a common, highly contagious infection. Symptoms usually include abdominal discomfort, nausea, vomiting, diarrhea, and bloating. The infection usually resolves on its own within a few days, but sometimes, treatment with IV fluids and electrolytes is necessary.

Ovarian Cancer

Ovarian cancer isn't the most common cause of abdominal swelling and bloating, but persistent, long-term bloating is one of the earliest signs of this disease. It is also a symptom that is frequently ignored. The bloating may be so bad that one can't button their pants or may even have to go up a size.

There's no screening test for ovarian cancer, so it's essential to pay close attention to bloating that occurs outside your monthly cycle, especially if it's accompanied by pain, changes in bladder function, or constipation.

Other Cancers

Though tumors are not a common cause of abdominal swelling or bloating, they are serious ones. Tumors anywhere in the abdominal or pelvic region can be large enough to cause visible swelling or a lump that you can feel with your hands. More commonly, a tumor can cause inflammation, bowel obstruction, or ascites (fluid buildup in the abdomen)—which may lead to swelling.

• Colon cancer: While colon cancer usually doesn't cause abdominal swelling in the early stages, an intestinal blockage from the tumor can lead to abdominal swelling.
• Non-Hodgkin lymphoma: Lymphoma is a type of white blood cell cancer. Non-Hodgkin lymphoma causes swelling of lymph nodes throughout the body, and it can cause abdominal swelling or discomfort.
  
• Stomach cancer: Gastric (stomach) cancer can cause a loss of appetite, indigestion, heartburn, or bloating after eating.
• Uterine cancer: Symptoms of uterine cancer include abnormal bleeding or heavy bleeding, vaginal discharge, changes in bowel movements, sudden weight loss, and abdominal bloating. Vaginal bleeding after menopause can be one of the signs of this disease.

When to See a Healthcare Provider

Abdominal bloating is very common, but abdominal swelling is not. Sometimes, bloating is a sign that you ate too much, and sometimes, it is a sign of a medical condition. If your symptoms are worsening or persistent, talk to your healthcare provider.

Get urgent medical attention if your bloating or abdominal swelling is accompanied by:

• Fever
• Uncontrolled or excessive vomiting
• Blood in vomit or stool
• Uncontrolled diarrhea
• No bowel movements for three days or longer
• Severe pain or tenderness
• Dizziness, changes in consciousness

If you are worried, it's better to talk to your provider or get medical attention than wait.

Diagnosing Abdominal Bloating

Often, abdominal bloating is nonspecific in location, and pain can radiate (travel) from its source to another area. Because abdominal swelling and bloating have many causes, the diagnosis often has to be speedy. This can help you get prompt treatment for certain serious causes, such as bowel obstruction or appendicitis.

Your healthcare provider will first take your medical history and perform a physical examination to assess your abdominal bloating and swelling. You will be asked about the duration, pattern, and location of your pain, any associated symptoms you are experiencing, and whether anything makes it better or worse.

Your physical examination includes assessing whether you are in distress and your temperature, pulse, blood pressure, and breathing rate.

Your provider will examine you to determine whether you have a specific location of pain or swelling. For example, a sense of bloating in the upper abdominal area could be associated with a peptic ulcer, while swelling in the lower abdomen on one side is more likely to be associated with an ovarian cyst.

Diagnostic tests can include:

• Complete blood count (CBC): This blood test can detect low red blood cells, a sign of bleeding, or high white blood cells, a sign of infection or cancer.
  
• Urine test: This test can detect signs of a UTI.
  
• Stool analysis: A stool sample can be assessed for evidence of an infection.
  
• Imaging tests: An abdominal or pelvic computerized tomography (CT) scan or ultrasound can detect fluid, tumors, obstruction, and more.
  

Additional tests may include minimally invasive tests. During an endoscopy, a tube is placed into the throat; during a colonoscopy, a tube is placed in the colon so your doctor can view areas of potential disease.

Abdominal bloating and swelling can be uncomfortable or even painful. Though the cause isn't always serious, you should talk to your healthcare provider if you have bloating that doesn't come and go, fails to respond to self-care treatment at home, or if it lasts more than a week or two,

Your healthcare provider will be able to determine what is causing your discomfort and help you find relief from your symptoms. They'll also be able to coordinate treatment for the underlying cause.

Self-Care for Bloating

Simple abdominal bloating without symptoms of concern may respond well to self-care at home. Some things you can try include:

• Drink more water: Increasing fluid intake can flush your system and help constipation.
• Simplify your diet: Avoiding spicy foods in favor of more bland ones, like rice, applesauce, and toast, can alleviate stomach and GI troubles that cause bloating, like diarrhea, and minimize flares from conditions like Crohn's disease. Avoid foods you may not tolerate, such as gluten or dairy.
• Consider medications: If gas is causing you to bloat, digestive enzymes or simethicone medicines (like Gas-X) may help. If you have pain in your abdomen, avoid non-steroidal anti-inflammatory drugs like ibuprofen or aspirin until your physician has ruled out a stomach condition like an ulcer. These drugs could increase bleeding.
  
• Drink herbal tea: Some herbal compounds like peppermint, turmeric, and ginger have been shown to have a clinically significant impact on some conditions that lead to bloating. What is unclear is whether peppermint tea has enough to produce a significant result. However, the warmth alone from the tea can be soothing and aid in increasing hydration.
• Probiotics: Studies have shown that increased consumption of probiotics can positively impact symptoms of irritable bowel syndrome, including bloating. However, the reasons for this are not fully understood.

Preventing Bloating

Preventing bloating will depend on whether you can pinpoint the cause of your bloating. Here are some tips to prevent bloating:

• Stay hydrated.
• Avoid food you don't tolerate well.
• Eat slowly, taking breaks between bites.
• Try a low-FODMAP diet.
• Exercise regularly.

Summary

The feeling of abdominal bloating is uncomfortable, and yet it can be difficult to pinpoint the exact cause. Food, including diet, food intolerance, and eating habits, as well as diseases like cancer and infections, can all be contributing factors. If bloating is persistent, painful, or accompanied by other worrying symptoms, see a healthcare provider. In the meantime, eating a simple diet, staying hydrated, and eating slowly can all be beneficial in minimizing bloating.