(See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.)
Hepatitis is common throughout the world.
Hepatitis can be
Most cases of acute hepatitis caused by a virus (acute viral hepatitis) resolve on their own, but some progress to chronic hepatitis.
Causes
Hepatitis commonly results from
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A virus, particularly one of the five major hepatitis viruses—A, B, C, D, or E
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Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH)
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Use of certain drugs, such as isoniazid (used to treat tuberculosis)
Less commonly, hepatitis results from a reaction of the immune system that causes inflammation of the liver (autoimmune hepatitis), genetic liver disorders, and other infections (such as infectious mononucleosis, herpes simplex, or cytomegalovirus infection).
The Hepatitis Viruses
Transmission |
Symptoms and Prognosis |
Prevention |
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Ingestion of something contaminated with the stool of an infected person), usually because of poor hygiene or inadequate sanitation (called the fecal-oral route). |
Usually no symptoms in young children Usually in older children and adults, typical symptoms of acute hepatitis (poor appetite, nausea, vomiting, and often jaundice) Usually complete recovery Does not become chronic |
Use of good hygiene when handling food and avoidance of contaminated water Vaccination against hepatitis A for all children (see figure Vaccinating Infants and Children) and for adults likely to be exposed to the infection If people are exposed to hepatitis A, hepatitis A vaccine or standard immune globulin* |
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Less easily transmitted than hepatitis A Contact with blood and other body fluids (such as semen, vaginal fluids, or saliva)—as occurs during the following: |
Generally more serious than hepatitis A and occasionally fatal More severe symptoms when people with hepatitis B also have hepatitis D Joint pains and itchy red hives on the skin (wheals) in addition to typical symptoms of acute hepatitis Can become chronic, with increased risk of liver cancer |
Avoidance of high-risk behavior, such as sharing needles to inject drugs and having several sex partners Vaccination against hepatitis B for all children (starting at birth—see figure Vaccinating Infants and Children) and for people likely to be exposed to the infection If people are exposed to hepatitis B (including babies born to mothers with hepatitis B), hepatitis B immune globulin* and the vaccine |
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Contact with blood and other body fluids (such as semen, vaginal fluids, or saliva)—as occurs during the following: |
At first, usually mild or no symptoms but sometimes alternating between mild and more severe symptoms Becomes chronic in about 75% of people, with increased risk of severe scarring of the liver (cirrhosis) and liver cancer, but usually only if cirrhosis has developed first |
Avoidance of high-risk behavior, such as sharing needles to inject drugs and getting tattoos and body piercings No vaccine currently available |
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Contact with blood and other body fluids (such as semen, vaginal fluids, or saliva)—as occurs during the following: |
Occurs only as a coinfection with hepatitis B and usually makes the hepatitis B infection more severe |
Same as for hepatitis B: |
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Ingestion of something contaminated with the stool of an infected person, usually because of poor hygiene or inadequate sanitation (called the fecal-oral route) Occasionally consumption of meat from an infected animal |
Severe symptoms, especially in pregnant women Does not usually become chronic |
Vaccination against hepatitis E (currently, available only in China) |
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* Standard immune globulin is a preparation containing antibodies obtained from the blood (plasma) of people with a normal immune system. It is used to treat a variety of diseases. Hepatitis B immune globulin contains antibodies obtained from the blood of people who have high levels of antibodies to hepatitis. It is given by injection into a muscle or into a vein. |
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† A pregnant woman infected with hepatitis B or hepatitis C can transmit the virus to her baby. |
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