Liver disease has many causes.
Infection
Parasites and viruses can infect the liver, causing inflammation that reduces liver function. The viruses that cause liver damage can be spread through blood or semen, contaminated food or water, or close contact with a person who is infected. The most common types of liver infection are hepatitis viruses, including:
Hepatitis A
Hepatitis B
Hepatitis C
Immune system abnormality
Diseases in which your immune system attacks certain parts of your body (autoimmune) can affect your liver. Examples of autoimmune liver diseases include:
Autoimmune hepatitis
Primary biliary cirrhosis
Primary sclerosing cholangitis
Genetics
An abnormal gene inherited from one or both of your parents can cause various substances to build up in your liver, resulting in liver damage. Genetic liver diseases include:
Hemochromatosis
Hyperoxaluria and oxalosis
Wilson's disease
Alpha-1 antitrypsin deficiency
Cancer and other growths
Examples include:
Liver cancer
Bile duct cancer
Liver adenoma
Other
Additional, common causes of liver disease include:
Chronic alcohol abuse
Fat accumulating in the liver (nonalcoholic fatty liver disease)