15 Common Causes of Ascites

2. Acute Liver Failure

Acute liver failure happens when your liver stops working over a short time, often within days or weeks. This sudden loss of function can lead to fluid buildup in your abdomen, known as ascites. The liver makes important proteins and controls blood flow, so when it fails, fluid can leak into your belly.

Several problems can trigger acute liver failure, including an overdose of certain pain relievers, severe viral hepatitis infections, reactions to some medications, and exposure to toxins or poisonous substances. When your liver fails, pressure rises in the veins that pass through it, and low protein levels in your blood also allow fluid to collect in the abdominal space.

You may notice rapid swelling in your abdomen along with yellowing of your skin or eyes, confusion, nausea, or easy bruising. These signs show that your liver cannot filter toxins or support clotting.

3. Budd-Chiari Syndrome

Budd-Chiari syndrome happens when a blockage prevents blood from leaving your liver through the hepatic veins. This blockage causes blood to back up inside the liver. As pressure increases, fluid can leak into your abdomen and cause ascites. The rising pressure also affects normal liver function.

You may notice swelling in your belly, pain in the upper right abdomen, and swelling in your legs. Fatigue, yellowing of the skin or eyes, and weight gain from fluid buildup can also occur. In severe cases, liver failure may develop and lead to confusion or easy bleeding.

Blood clots cause most cases, especially in people with disorders that increase clotting risk, while tumors or growths can also block blood flow. Imaging tests such as ultrasound, CT scan, or MRI are used to evaluate the liver veins. Treatment includes vein procedures to restore blood flow, anticoagulant medication to prevent new clots, and advanced care to address liver failure.

4. Heart Failure

Heart failure happens when your heart cannot pump enough blood to meet your body’s needs. When this occurs, blood backs up in your veins. The extra pressure can force fluid out of blood vessels and into your abdomen. This fluid buildup can lead to ascites and abdominal swelling.

You may first notice swelling in your legs or ankles. As fluid increases, your belly may feel tight, heavy, or bloated. Shortness of breath can also occur because fluid may collect in your lungs. Rapid weight gain often reflects fluid retention rather than fat gain.

Heart failure can follow coronary artery disease, long-term high blood pressure, or past heart attacks that weaken the heart muscle. Doctors check for swollen legs, enlarged neck veins, and abdominal fluid. Treatment includes diuretics to lower fluid levels, salt restriction to reduce fluid retention, and regular weight monitoring to track changes.

5. Nephrotic Syndrome

Nephrotic syndrome is a kidney disorder that causes you to lose large amounts of protein in your urine. Your kidneys normally keep protein in your blood. When the kidney filters become damaged, protein leaks out. Low protein levels in your blood allow fluid to shift into tissues and body spaces.

This fluid shift can cause swelling in your legs, feet, face, and abdomen. When fluid collects in your abdominal cavity, ascites can develop. You may also notice foamy urine, weight gain from fluid retention, and fatigue. Blood tests often show low protein and high cholesterol levels.

Several conditions can damage the kidney filters, including diabetes, immune disorders, and inflammatory diseases. In children, a structural change in kidney tissue is a common cause. Treatment includes blood pressure medicines to control pressure, immune-suppressing drugs to manage underlying disease, diuretics to reduce fluid buildup, and cholesterol-lowering medicines to address lipid levels.

6. Acute Pancreatitis

Acute pancreatitis happens when your pancreas becomes inflamed over a short time. Your pancreas sits behind your stomach and helps digest food and control blood sugar. When it becomes irritated, digestive enzymes can damage the gland itself and cause swelling and pain.

Gallstones and heavy alcohol use are the most common causes. Gallstones can block the duct that drains the pancreas. Long-term heavy drinking or binge drinking can inflame pancreatic tissue. High blood fat levels, infections, injury, and certain medicines such as corticosteroids or some diuretics can also trigger an attack.

You usually feel sudden, severe pain in your upper abdomen that may spread to your back and worsen after eating. Nausea, vomiting, fever, and abdominal swelling are common. Severe cases can lead to fluid buildup, infection, bleeding, or organ failure.

7. Chronic Pancreatitis

Chronic pancreatitis is long-term inflammation and damage of your pancreas. Your pancreas helps digest food and control blood sugar. When it stays inflamed for years, scar tissue forms and normal function declines. This damage can affect digestion, nutrition, and blood sugar control over time.

Repeated attacks of acute pancreatitis often lead to this condition. Heavy alcohol use is a common cause. Smoking, very high blood fat levels, autoimmune disease, and inherited gene changes can also play a role. In some cases, no clear cause is found after testing.

As damage progresses, you may notice weight loss, oily stools, and ongoing upper abdominal pain that spreads to your back. Diabetes can develop if insulin production drops. Ascites may occur if pancreatic fluid leaks or nearby veins become affected.

8. Peritoneum Irritation

Your peritoneum is a thin layer of tissue that lines the inside of your abdomen and covers most of your organs. When this lining becomes irritated or inflamed, extra fluid can collect in your belly. This buildup can lead to ascites and visible abdominal swelling.

Infection is a common cause. Bacteria can enter the abdominal space and cause peritonitis. You may feel severe belly pain, tenderness, fever, nausea, or swelling. Injury such as a ruptured appendix, a tear in the intestine, or blunt trauma can also release blood or bacteria into the cavity and trigger inflammation.

Long-term liver disease increases the risk because existing fluid can become infected. Abdominal surgery may also lead to irritation if infection develops afterward. Ongoing inflammation causes continued fluid production and abdominal tightness. Peritoneal irritation is a serious condition, and it requires immediate medical treatment to prevent life-threatening complications.

9. Constrictive Pericarditis

Constrictive pericarditis happens when the sac around your heart becomes thick and stiff. This sac, called the pericardium, normally stretches as your heart fills with blood. When it becomes rigid, it limits how much blood your heart can hold between beats and reduces normal filling.

As pressure builds, blood backs up in your veins. Fluid can then leak into your abdomen and cause ascites. You may also notice swelling in your legs and feet. This backup affects circulation and makes it harder for your heart to pump blood forward.

Common causes include prior heart surgery, chest radiation therapy, and infections such as tuberculosis. Long-term inflammation can scar the heart lining. You may feel short of breath, tired, or have chest discomfort that changes with position.

10. Kwashiorkor

Kwashiorkor is a severe form of protein malnutrition. It often affects young children in areas with famine or limited food supply. It can also occur in adults with very poor diets or chronic illness. Without enough protein, your body cannot maintain normal growth and repair.

When you do not get enough protein, your body makes less albumin. Albumin is a blood protein that keeps fluid inside your blood vessels. Low albumin levels allow fluid to leak into tissues and body spaces. This shift can lead to ascites and swelling in your abdomen.

You may notice a round, tight belly along with swelling in your legs, feet, or face. Other signs include muscle wasting, weight loss, dry or peeling skin, hair changes, fatigue, irritability, and slow growth in children.

11. Serositis

Serositis is inflammation of the thin lining that covers your organs and lines your abdomen, called the peritoneum. When it becomes inflamed, fluid can leak into your abdominal space and cause ascites. The inflammation may also affect the lining around your lungs or heart.

Serositis often occurs as part of an autoimmune disease. In these conditions, your immune system attacks healthy tissue. Lupus and certain types of arthritis can inflame the linings of the abdomen, lungs, or heart. Inflammation increases blood vessel permeability, which allows fluid and proteins to move into nearby spaces.

You may notice abdominal swelling, chest pain if the lung or heart lining is involved, joint pain, skin rashes, or fever. Treatment focuses on reducing inflammation using anti-inflammatory drugs, corticosteroids, or other immune-suppressing medicines.

12. Hypothyroidism

Hypothyroidism happens when your thyroid gland does not make enough thyroid hormone. This small gland sits at the front of your neck and controls how your body uses energy. When hormone levels drop, many body systems slow down, including your heart rate, digestion, and fluid balance.

Low thyroid hormone can cause fluid buildup in different parts of your body. In some cases, fluid collects in your abdomen and leads to ascites. Slower body processes affect how blood vessels and proteins manage fluid, which allows extra fluid to move into tissues and body spaces.

The most common cause is Hashimoto’s disease, an autoimmune condition. Other causes include thyroid inflammation, surgery, radiation, certain medicines, and iodine imbalance. You may notice tiredness, weight gain, feeling cold, dry skin, constipation, a slow heart rate, or a puffy face. Doctors confirm the diagnosis with blood tests. Treatment involves thyroid hormone replacement therapy to restore normal levels and reduce fluid buildup over time.

13. Mastocytosis

Mastocytosis is a rare disorder in which your body produces too many mast cells. Mast cells are white blood cells that help with allergic reactions. In this condition, they build up in organs and release excess chemicals that cause inflammation and tissue damage.

When mast cells collect in your liver, they can interfere with normal function. Over time, this may increase pressure in the veins that pass through your liver. The higher pressure can force fluid into your abdomen and lead to ascites. Liver and spleen enlargement may also occur in more severe cases.

You may notice flushing, itching, stomach pain, nausea, diarrhea, fatigue, headaches, low blood pressure, or trouble breathing. Many cases link to a change in the KIT gene, which keeps mast cells active and contributes to their buildup in the body.

14. Ovarian Cancer

Ovarian cancer starts in your ovaries, which sit on each side of your uterus. It can also begin in nearby areas such as the fallopian tubes or the lining of your abdomen. When cancer spreads to the abdominal lining, it can cause fluid buildup known as ascites.

Cancer cells can irritate the tissue that covers your abdominal organs. This irritation increases fluid production. Tumors can also block normal fluid drainage, which allows fluid to collect in your belly. As fluid builds up, your abdomen may look swollen or feel firm and heavy.

You may feel pressure, pain, or fullness after small meals. Breathing can become harder if swelling pushes against your lungs. Other signs include ongoing bloating, pelvic pain, bowel changes, frequent urination, and unexplained weight changes.

15. Alcohol Abuse

Long-term alcohol abuse can damage your liver and lead to ascites. Heavy drinking over many years causes inflammation and scarring of liver tissue. This scarring can progress to cirrhosis, which blocks normal blood flow through your liver and disrupts its ability to manage fluid balance.

As pressure rises in the liver’s blood vessels, fluid can leak into your abdomen. A damaged liver also produces less albumin, a protein that keeps fluid inside your bloodstream. Low albumin levels allow more fluid to collect in your belly and worsen swelling over time.

You may notice gradual abdominal swelling that feels tight or heavy. In severe cases, fluid can press on your lungs and make breathing difficult. Alcohol abuse also weakens your immune system, which increases the risk of infection in the trapped fluid. Other signs of advanced liver damage include yellowing of your skin or eyes, easy bruising, and confusion.