Esophageal varices usually don't cause signs and symptoms unless they bleed. Signs and symptoms of bleeding esophageal varices include:

• Vomiting large amounts of blood
• Black, tarry or bloody stools
• Lightheadedness
• Loss of consciousness in severe cases

Your doctor might suspect esophageal varices if you have signs of liver disease, including:

• Yellow coloration of your skin and eyes (jaundice)
• Easy bleeding or bruising
• Fluid buildup in your abdomen (ascites)

Esophageal varices sometimes form when blood flow to your liver is blocked, most often by scar tissue in the liver caused by liver disease. The blood flow begins to back up, increasing pressure within the large vein (portal vein) that carries blood to your liver.

This increased pressure (portal hypertension) forces the blood to seek other pathways through smaller veins, such as those in the lowest part of the esophagus. These thin-walled veins balloon with the added blood. Sometimes the veins rupture and bleed.

Causes of esophageal varices include:

• Severe liver scarring (cirrhosis). A number of liver diseases — including hepatitis infection, alcoholic liver disease, fatty liver disease and a bile duct disorder called primary biliary cirrhosis — can result in cirrhosis.
• Blood clot (thrombosis). A blood clot in the portal vein or in a vein that feeds into the portal vein (splenic vein) can cause esophageal varices.
• Parasitic infection. Schistosomiasis is a parasitic infection found in parts of Africa, South America, the Caribbean, the Middle East and East Asia. The parasite can damage the liver, as well as the lungs, intestine, bladder and other organs.

Although many people with advanced liver disease develop esophageal varices, most won't have bleeding. Esophageal varices are more likely to bleed if you have:

• High portal vein pressure. The risk of bleeding increases as the pressure in the portal vein increases (portal hypertension).
• Large varices. The larger the esophageal varices, the more likely they are to bleed.
• Red marks on the varices. When viewed through a thin, flexible tube (endoscope) passed down your throat, some esophageal varices show long, red streaks or red spots. These marks indicate a high risk of bleeding.
• Severe cirrhosis or liver failure. Most often, the more severe your liver disease, the more likely esophageal varices are to bleed.
• Continued alcohol use. Your risk of variceal bleeding is far greater if you continue to drink than if you stop, especially if your disease is alcohol related.

If you've had bleeding from esophageal varices before, you're more likely to have varices that bleed again.

The most serious complication of esophageal varices is bleeding. Once you've had a bleeding episode, your risk of another bleeding episode greatly increases. If you lose enough blood, you can go into shock, which can lead to death.