Acute viral hepatitis is inflammation of the liver caused by infection with one of the five hepatitis viruses. In most people, the inflammation begins suddenly and lasts only a few weeks.
Acute viral hepatitis can be caused by five hepatitis viruses (A, B, C, D, and E—see Table 1: The Hepatitis Viruses) and probably other as yet unidentified viruses. Hepatitis A virus is the most common cause, followed by hepatitis B virus. Engaging in certain activities, such as getting a tattoo or body piercing, sharing needles to inject drugs, or having several sex partners, increases the risk of developing hepatitis.
Acute viral hepatitis can cause anything from a minor flu-like illness to fatal liver failure. Sometimes there are no symptoms. The severity of symptoms and speed of recovery vary considerably, depending on the particular virus and on the person's response to the infection. Hepatitis A and C often cause very mild symptoms or none at all and may be unnoticed. Hepatitis B and E are more likely to produce severe symptoms. Infection with both hepatitis B and D (called coinfection) may make the symptoms even more severe.
Symptoms usually begin suddenly. They include a poor appetite, nausea, vomiting, and often a fever and pain in the upper right part of the abdomen (where the liver is located). In people who smoke, a distaste for cigarettes is a typical symptom. Occasionally, especially with hepatitis B, infected people develop joint pains and itchy red hives on the skin (wheals or urticaria).
Typically, after 3 to 10 days, the urine becomes dark, and jaundice (a yellowish discoloration of the skin and whites of the eyes—see Jaundice in Adults) develops. Both of these symptoms occur because bilirubin builds up in the blood. Bilirubin is the main pigment in bile, the greenish yellow digestive fluid produced by the liver. Most symptoms usually disappear at this point, and people feel better even though the jaundice may worsen. The jaundice usually peaks in 1 to 2 weeks, then fades over 2 to 4 weeks. Symptoms of cholestasis (a reduction or stoppage of bile flow)—such as pale stools and overall itchiness—may develop, particularly in people with hepatitis A.
Rarely, symptoms become extremely severe and liver failure develops (called fulminant hepatitis). Fulminant hepatitis is more likely to develop in people with hepatitis B, particularly if they also have hepatitis D. Fulminant hepatitis can progress very quickly. Toxic substances normally removed by the liver build up in the blood and reach the brain, causing hepatic (portosystemic) encephalopathy (see Hepatic Encephalopathy). Fulminant hepatitis may be fatal, especially in adults.
People with acute viral hepatitis usually recover in 4 to 8 weeks, even without treatment. However, people infected with hepatitis C may become carriers of the virus. People infected with hepatitis B are less likely to become carriers. Carriers have no symptoms but are still infected and can transmit the virus to others. Carriers may develop chronic hepatitis even though the disease is not apparent. Carriers may eventually develop cirrhosis (severe scarring of the liver—see Cirrhosis of the Liver) or liver cancer (see Primary Liver Cancers).
Doctors suspect acute viral hepatitis on the basis of symptoms. During the physical examination, a doctor presses on the abdomen above the liver, which is tender and somewhat enlarged in about half of the people with acute viral hepatitis.
Blood tests to determine how well the liver is functioning and whether it is damaged (liver function tests) are done. They can indicate whether the liver is inflamed and often help doctors distinguish hepatitis due to alcohol abuse from that due to a virus. Blood tests are done to help doctors identify which hepatitis virus is causing the infection. These tests can detect parts of the viruses or specific antibodies produced by the body to fight the viruses.
Occasionally, if the diagnosis is unclear, a biopsy is done: A sample of liver tissue is removed with a needle and examined.
If acute hepatitis seems likely, the cause is identified if possible. To help identify the cause, a doctor usually asks about activities that can increase the risk of getting viral hepatitis (see Table 1: The Hepatitis Viruses). To determine whether the cause may be something other than a virus, the doctor may ask whether people take any drugs that can cause hepatitis (such as isoniazid, used to treat tuberculosis) and how much alcohol they drink.
Vaccines, given by injection into muscle, are available to prevent hepatitis A, B, and E infections.
As with most vaccines, protection requires allowing a number of weeks for the vaccine to reach its full effect as the immune system gradually creates antibodies against the particular virus.
If people who have not been vaccinated are exposed to hepatitis A virus, they can be given an injection of an antibody preparation called standard immune globulin. It prevents infection or decreases its severity. However, the amount of protection it provides varies, and the protection is only temporary.
If people who have not been vaccinated are exposed to hepatitis B virus, they are given hepatitis B immune globulin and are vaccinated. Hepatitis B immune globulin contains antibodies to hepatitis B, which help the body fight the infection. This preparation prevents symptoms or decreases their severity, although it is unlikely to prevent infection. Some people, such as those with a weakened immune system or those being treated with hemodialysis, may need a booster dose of the vaccine.
No vaccines against hepatitis C or D virus are available. However, vaccination against hepatitis B virus also reduces the risk of infection with hepatitis D virus.
Other preventive measures against infection with the hepatitis viruses can be taken:
Donated blood is unlikely to be contaminated because it is screened. Nonetheless, doctors help reduce the risk of hepatitis by ordering blood transfusions only when essential. Before surgery, people can also sometimes prevent the need for transfusion of blood from an unknown donor by donating their own blood weeks before the operation.
In most people, special treatment is not necessary, although people with unusually severe acute hepatitis may require hospitalization. After the first several days, appetite usually returns and people do not need to stay in bed. Severe restrictions of diet or activity are unnecessary, and vitamin supplements are not required. Most people can safely return to work after the jaundice clears, even if their liver function test results are not quite normal.
People with hepatitis should not drink alcohol until they have fully recovered. A doctor may need to stop a drug or reduce the dosage of a drug that could accumulate to harmful levels in the body (such as warfarin or theophylline) because the infected liver cannot process (metabolize) them. Thus, people should tell their doctor all the drugs they are taking (both prescription and nonprescription, including any medicinal herbs), so that the dosage can be adjusted if necessary.
If hepatitis B causes extremely severe (fulminant) hepatitis, antiviral drugs may help. However, liver transplantation is the most effective treatment and may be the only hope of survival, particularly for adults.
Last full review/revision September 2014 by Anna E. Rutherford, MD, MPH