Hepatitis, or inflammation of the liver, can be caused by viruses, heavy alcohol use, fat accumulation in the liver and several other factors. Over time, this inflammation can lead to the buildup of scar tissue (fibrosis) and impaired liver function.
Hepatitis A virus is transmitted through food or water contaminated with feces. It causes an acute form of hepatitis, meaning it doesn’t lead to chronic, or long-term, infection. Hepatitis A usually resolves on its own with supportive care, but in some cases, it can cause fatal liver disease. A person who has had hepatitis A once cannot get the virus again.
Hepatitis B is a blood-borne virus that can be transmitted through sex, from mother to child during pregnancy and via shared needles or personal items, such as razors. About 90% of people infected as infants develop chronic disease, but most adults clear the virus naturally and recover. Hepatitis B can be treated with antiviral drugs or interferon, but it is seldom cured. A person who has had hepatitis B once cannot get it again.
Hepatitis C is another blood-borne virus that is transmitted in similar ways, although sexual transmission is less common. About a quarter of adults clear the virus naturally, but the rest develop chronic infection. Hepatitis C can be treated with well-tolerated direct-acting antiviral medications for two or three months, and almost everyone can be cured. However, it is possible to acquire hepatitis C again after natural clearance or successful treatment.
Hepatitis D, or delta, is a defective virus that occurs only in people with hepatitis B, and it is transmitted in similar ways. Coinfection with both hepatitis B and D can lead to more severe liver disease. There are no approved treatments for hepatitis D, but controlling hepatitis B with antivirals can keep it in check.
Hepatitis E, which is uncommon in the United States, is transmitted through contaminated food or water, like hepatitis A. It usually resolves on its own without treatment, but it can cause more serious illness in pregnant women and immunocompromised people.
Regardless of the cause, hepatitis symptoms can include fatigue, nausea, loss of appetite, pain in the upper right abdomen, yellowing of the skin and whites of the eyes (jaundice), dark urine, pale stools and elevated ALT and AST liver enzymes.
All types of viral hepatitis can be detected using blood tests for antibodies against the specific virus. Hepatitis B screening is recommended for anyone at risk, including people who inject drugs, men who have sex with men, people who have sexual or household contact with a person with hep B, people living with HIV, pregnant people, those with potential occupational exposure and those born in countries with a high prevalence of the virus. Hepatitis C screening is recommended at least once for all adults.
Many people with hepatitis B or C have no early symptoms and are not aware that they carry the virus. However, they can still transmit the virus even if they feel well. Over years or decades, chronic infection can lead to serious liver disease, including cirrhosis, liver cancer, liver failure and the need for a liver transplant.
Hepatitis A and B can be prevented with vaccines. Vaccination is recommended for all babies and for adults at risk. Combination vaccines can prevent both hepatitis A and B, and preventing hepatitis B also prevents hepatitis D. There is no vaccine for hepatitis C, but this is an active area of research.