Hepatitis D virus is infection of the liver that occurs only in people who have hepatitis B.
Hepatitis D can be spread by contact with blood and other body fluids.
Coinfection with hepatitis D usually makes symptoms of hepatitis B worse.
Doctors diagnose chronic hepatitis D based on blood tests.
There is no specific treatment for acute hepatitis D, but chronic hepatitis D may be treated with interferon alfa.
(See also Overview of Hepatitis, Overview of Acute Viral Hepatitis, Overview of Chronic Hepatitis, Hepatitis B, Acute, and Hepatitis B, Chronic.)
Hepatitis D is relatively rare in the United States. It can be an acute infection, lasting only a short time, or a chronic infection, lasting more than 6 months.
Hepatitis D occurs only as a coinfection with acute hepatitis B or chronic hepatitis B. The hepatitis D virus is an incomplete virus that requires the help of the hepatitis B virus to reproduce.
Worldwide, about 15 to 20 million people have chronic hepatitis B and hepatitis D coinfection.
Transmission of hepatitis D
Hepatitis D can be spread by contact with blood and other body fluids. Hepatitis D is most often spread when people share unsterilized needles to inject illicit drugs. It can also be spread through sexual activity.
Symptoms of Hepatitis D
Coinfection with hepatitis D usually makes the hepatitis B infection more severe.
Chronic coinfection with hepatitis B and D, if untreated, can cause severe scarring of the liver (cirrhosis).
Coinfection with hepatitis B and D can lead to fulminant hepatitis (a very severe form of hepatitis). 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. People may lapse into a coma within days to weeks. Fulminant hepatitis may be fatal, especially in adults.
Diagnosis of Hepatitis D
Blood tests
Doctors may suspect hepatitis D when
Acute hepatitis B is unusually severe (coinfection).
Chronic hepatitis B suddenly becomes much worse (superinfection) in people who are chronically infected with hepatitis B.
Chronic hepatitis B progresses more rapidly than it typically does.
If hepatitis D is suspected, a blood test to detect antibodies produced by the person's immune system in response to the hepatitis virus D is done to confirm the diagnosis.
Prevention of Hepatitis D
Avoiding high-risk behavior (such as sharing needles to inject drugs and having multiple sex partners) helps prevent people from getting hepatitis B and thus from getting hepatitis D.
There is no vaccine for hepatitis D. But if people do not already have hepatitis B, they can be vaccinated with the hepatitis B vaccine, which can prevent hepatitis D as well as hepatitis B.
Treatment of Hepatitis D
General measures
Interferon alfa (an antiviral drug)
People with hepatitis D should not drink alcohol because it can damage the liver further. There is no need to avoid certain foods or limit activity.
There is no specific treatment for acute viral hepatitis D.
Chronic hepatitis D may be treated with interferon alfa, usually for 1 year.
If fulminant hepatitis develops, liver transplantation is the most effective treatment and is the best hope of survival, particularly for adults.
