Causes of Abdominal Swelling and Bloating

Most people experience abdominal bloating or swelling at some point in their lives. These are common symptoms that can have a variety of causes—from simply swallowing too much air to serious conditions like ovarian cancer.

Depending on what's causing your bloating, it can come on suddenly or gradually. In some cases, it can come and go, or persist for a period of time. 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.

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

Causes of Abdominal Swelling and Bloating

Many conditions or lifestyle behaviors can cause bloating and swelling in the abdomen, including the following examples.

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 important 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

Symptoms of colon cancer include changes in bowel habits, loss of appetite, abdominal discomfort, nausea, vomiting, and fatigue. The cancer usually doesn't cause abdominal swelling in the early stages, but 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 abdominal discomfort.

Pancreatic Cancer

Pancreatic cancer is hard to detect initially but can have more specific symptoms in later stages that include jaundice (yellowing of the eyes or skin), pain in the upper abdomen that radiates to the back, nausea, loss of appetite, vomiting, and weight loss. Bloating and abdominal swelling are less common symptoms.

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.

Infections

Appendicitis

An infection of the appendix, appendicitis can cause severe pain, fever, inflammation, and sometimes bloating. Appendicitis is a serious condition that may spread to other areas of the gastrointestinal system, or cause the appendix to rupture. These complications are life-threatening, and urgent treatment often includes surgery. Sometimes, antibiotics are prescribed.

Diverticulitis

Diverticulitis is a painful condition that affects the colon. Abdominal pain is the most common symptom, along with fever, cramping, constipation, chills, or vomiting. Bloating is rare, but can occur.

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, it can 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 with urination. Sometimes the abdomen may feel like it's 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. Most of the time, the infection resolves on its own within a few days, but sometimes treatment with IV fluids and electrolytes is necessary.

Diet, Eating Habits, and Food Intolerances

Overeating can cause you to feel bloated, and 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 from chewing gum can also cause bloating.

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.

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.

For some people, gaining weight can lead to bloating and a sense that the stomach is always "full" or swollen. Often, weight gain causes previously comfortable clothes to feel tight on the abdomen. Being overweight or obese is also a risk factor for heartburn.

Other Causes

In addition to ovarian cancer, a number of other conditions can also cause abdominal bloating.

Ascites

Ascites is a buildup of fluid in the abdomen, typically from liver cirrhosis or cancer. Additional symptoms that would indicate ascites include abdominal pain, loss of appetite, shortness of breath, nausea, and vomiting.

Colic

Though usually associated with babies, adults can have colic too. Colic in adults is typically caused by kidney stones, gallstones, or intestinal blockage. Bloating from colic is usually accompanied by pain and tenderness. Other symptoms can vary depending on what is causing the colic.

Constipation

Constipation is a common cause of abdominal swelling and bloating, and one that many people experience at some point in their life. Other symptoms that would indicate constipation include having fewer than three bowel movements per week, straining to use the bathroom, and hard stools. There are many causes of constipation, among them diet, medication, and pregnancy.

Crohn's Disease

Crohn's disease is a type of chronic inflammatory bowel disease that causes gas, cramping, nausea, vomiting, and sometimes blood in the stool.

Cystic Fibrosis

Cystic fibrosis (CF) affects the body in many ways, including the digestive system. CF can impact the pancreas, interfering with the enzymes it makes that aid digestion. Undigested food can then cause many gastrointestinal symptoms, including bloating, gas, and greasy or loose stools.

Dumping Syndrome

When food moves too quickly from the stomach to the duodenum and large intestine, it can cause a condition called dumping syndrome that can cause bloating. Dumping syndrome is sometimes a complication of stomach surgery or esophageal surgery.

Dyspepsia

Also known as indigestion, dyspepsia can cause abdominal discomfort, including bloating. Symptoms also include belching, a painful or burning sensation, or nausea.

Ectopic Pregnancy

When a fertilized egg implants outside of the uterus, it is an ectopic pregnancy. This can cause severe pain, and sometimes it may cause abdominal swelling, usually on one side.

Endometriosis

A chronic condition, endometriosis occurs when endometrial tissue—the tissue that lines the uterus—also grows in other areas of the pelvis and abdomen, such as the ovaries. It can cause discomfort and swelling, often with a cyclical pattern that worsens before the menstrual period.

Gallstones

Gallstones are hard clumps that form in the gallbladder, causing pain and inflammation. They can be medically or surgically treated.

Gastroesophageal Reflux Disease (GERD) and Acid Reflux

Gastroesophageal reflux disease (GERD) causes frequent and bothersome acid reflux. It occurs when contents from the stomach are pushed into the esophagus, causing a burning sensation. One of the most common effects of GERD is abdominal bloating. Other symptoms include a dry cough, heartburn, hiccups, nausea, and sore throat.

Gastroparesis

When the stomach muscles don't move food as they should, it's called gastroparesis. This can cause discomfort, nausea, vomiting, bloating, and abdominal swelling. There are many causes of gastroparesis, including medication, viral infection, inflammatory disease, and muscle disease.

Hernia

There are many types of hernias. For example, a hiatal hernia is a protrusion of the stomach above the diaphragm. And an inguinal hernia is a bulging of the intestine in the inguinal canal, which is a small opening of tissue. These and other hernia types can cause swelling, pain, discomfort, and bloating.

Intestinal Obstruction

An intestinal obstruction (blockage) can be partial or complete. There are many causes of intestinal obstruction, including infections, cancer, and anatomical issues. Sometimes constipation can cause blockage as well. Obstruction may cause bloating, constipation, nausea, vomiting, and abdominal swelling. In severe cases it can be life threatening.

Irritable Bowel Syndrome

Up to 15% of the population is affected by irritable bowel syndrome, which results in recurrent abdominal bloating and swelling, along with other bowel symptoms.

Bloating is one of the most bothersome reported symptoms of IBS and it is caused by excessive gas. Additional symptoms include diarrhea, gas, and constipation.

Ovarian Cysts

Ovarian cysts can develop during the reproductive years of a woman's life and may not have any symptoms. Symptoms can occur when the cysts become large or ruptured, causing bloating, sudden onset of pain, delayed or irregular periods, or pain during sexual intercourse.

Pancreatic Insufficiency

Pancreatitis (infection or inflammation of the pancreas), cystic fibrosis, and inflammatory bowel disease are among the conditions that can affect the way the pancreas works. Insufficient pancreatic activity can lead to digestive problems, bloating, and abdominal swelling.

Peptic Ulcer Disease

A peptic ulcer is a stomach ulcer. It can cause discomfort, heartburn, gas, bloating, nausea, vomiting, and more.

Pregnancy

Pregnancy can cause bothersome GI symptoms, such as morning sickness. A growing fetus may cause a sensation that feels like bloating.

Premenstrual Syndrome (PMS)

For some women, hormonal shifts during the menstrual cycle can cause gastrointestinal (GI) symptoms, such as bloating, constipation, diarrhea, or abdominal pain. especially in the second half of the menstrual cycle after ovulation occurs.

Additionally, PMS and bloating can occur as common symptoms due to decreased estrogen levels before a woman's period.

Short Bowel Syndrome

Short bowel syndrome occurs when a portion of the bowel is surgically removed. These procedures may be done for treatment of cancer, bowel infarction, diverticulitis, or inflammatory bowel disease.

Weight loss surgeries often also involve removal of a section of the bowel.

This can cause a sense of abdominal fullness, bloating, or swelling. Generally, it is advised to eat slowly to avoid these symptoms.

Small Intestinal Bacterial Overgrowth (SIBO)

Small intestine bacterial overgrowth (SIBO) is a condition caused by an excessive amount of bacteria growing in the small intestines. Symptoms can include fatigue, weight loss, foul-odorous stools, bloating, diarrhea, or constipation.

Ulcerative Colitis

Ulcerative colitis can cause a variety of symptoms, including bloody diarrhea, frequent urgency to have a bowel movement, fever, loss of appetite, mucus in the stool, and bloating.

Uterine Fibroids

Uterine fibroids are growths in the uterus. They can cause cramping and discomfort, which can vary throughout the menstrual cycle. Sometimes uterine fibroids can be very large, and may cause abdominal swelling.

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, but sometimes it is a sign of a medical condition. If your symptoms are worsening or persistent, talk to your healthcare provider.

Symptoms of Concern

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 to wait it out.

Self-Care for Stomach Pain and 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 your fluid intake can flush your system and help with conditions such as 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 that you may not tolerate well, 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.

Diagnosing Abdominal Swelling and Bloating

Often, abdominal bloating is non-specific 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.

The first thing your healthcare providers will do in assessing your abdominal bloating and swelling is take your medical history and perform a physical examination. You will be asked about the duration, pattern, and location of your pain, as well as any associated symptoms you are experiencing and whether anything makes it better or worse.

Your physical examination includes an assessment of whether you are in distress, 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, and 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.