Hepatitis is inflammation of the liver, most often caused by a viral infection but also triggered by heavy alcohol use, certain medications, or an autoimmune condition. It can be a brief illness that resolves on its own or a chronic disease that slowly damages the liver over decades. Viral hepatitis alone kills roughly 3,500 people every day worldwide, according to a 2024 World Health Organization report.
How Hepatitis Damages the Liver
Your liver is made up of specialized cells called hepatocytes, which filter toxins, produce bile, and regulate dozens of metabolic processes. When a virus, toxin, or immune reaction injures these cells, they release distress signals that recruit your immune system. White blood cells flood the area and trigger inflammation, which is the body’s attempt to contain the threat and repair the tissue.
In a short-lived (acute) infection, this process works. The immune system clears the invader, inflammation subsides, and the liver heals. In chronic hepatitis, the cycle never fully stops. Ongoing inflammation generates reactive oxygen species, essentially unstable molecules that damage more liver cells and amplify the inflammatory cascade. Over time, the liver replaces healthy tissue with scar tissue, a process called fibrosis. If fibrosis progresses far enough, it becomes cirrhosis, where so much scarring accumulates that the liver can no longer function properly.
The Five Viral Types
Hepatitis A
Hepatitis A spreads through the fecal-oral route: contaminated water, undercooked shellfish, or close contact with an infected person. Its incubation period is about two to four weeks. The infection does not become chronic. Most people recover fully, though some experience a prolonged phase of jaundice or a relapsing course before clearing the virus. A highly effective vaccine prevents it.
Hepatitis B
Hepatitis B transmits through blood and body fluids: sexual contact, shared needles, contaminated piercing or tattooing equipment, and from mother to child during birth. Symptoms, when they appear, show up anywhere from 8 weeks to 5 months after exposure. Up to half of infected older children, adolescents, and adults develop noticeable symptoms; the rest may never know they were infected.
In adults, the rate of progression from acute to chronic hepatitis B is commonly cited at 5 to 10 percent, though some studies have found rates closer to 18 percent, particularly among older adults. Newborns infected at birth face a much higher risk, with up to 90 percent developing chronic infection. A vaccine series of two or three shots (depending on the brand) prevents hepatitis B and is now part of the routine childhood immunization schedule in most countries.
Hepatitis C
Hepatitis C spreads primarily through blood-to-blood contact, most commonly via shared needles. Unlike hepatitis A and B, there is no vaccine. The majority of people who contract hepatitis C develop a chronic infection. The good news: modern antiviral treatments cure 95 to 99 percent of cases, typically in 8 to 12 weeks of oral medication. Even among patients who fail a first round of treatment, re-treatment strategies achieve cure rates above 95 percent.
Hepatitis D and E
Hepatitis D only infects people who already have hepatitis B, because it depends on the hepatitis B virus to replicate. It spreads the same way as hepatitis B and makes existing liver disease worse. The hepatitis B vaccine indirectly protects against hepatitis D as well. Hepatitis E, like hepatitis A, spreads through contaminated water and food. It is usually self-limiting but can be dangerous for pregnant women and people with weakened immune systems.
Non-Viral Causes
Alcohol is one of the most common non-viral triggers. Heavy, sustained drinking causes fat to accumulate in liver cells, a condition called alcoholic fatty liver. Progression from fatty liver to active inflammation (alcoholic hepatitis) often requires a “second hit,” such as poor nutrition, exposure to another toxin, or a viral co-infection on top of the alcohol exposure.
Medications can also inflame the liver. Acetaminophen (Tylenol) is the classic example. It is safe at recommended doses, but overdoses are a leading cause of acute liver failure. Alcohol abuse makes the liver even more vulnerable to acetaminophen toxicity, so the combination is especially risky. Some prescription drugs, herbal supplements, and illicit substances carry hepatotoxic potential as well.
In autoimmune hepatitis, the immune system mistakenly attacks liver cells. It is less common than viral or alcohol-related forms and is typically managed with medications that suppress immune activity.
Symptoms to Recognize
Acute hepatitis, regardless of cause, tends to produce a recognizable set of symptoms:
- Jaundice: yellowing of the skin and whites of the eyes
- Dark urine and pale, clay-colored stools
- Fatigue that doesn’t improve with rest
- Nausea, vomiting, or stomach pain, especially in the upper right abdomen
- Fever and joint pain
- Loss of appetite
Symptoms of acute hepatitis B typically last several weeks, though some people feel sick for up to six months. Chronic hepatitis is often silent for years or even decades, producing no obvious symptoms until significant liver damage has already occurred. Many people with chronic hepatitis B or C are diagnosed only through routine blood work or screening.
How Hepatitis Is Diagnosed
A basic blood panel measures liver enzymes that leak into the bloodstream when hepatocytes are damaged. The two most important are ALT and AST. Normal ALT ranges from about 4 to 36 IU/L, and normal AST from about 5 to 30 IU/L, though exact reference ranges vary by lab. Elevated levels signal liver inflammation but don’t reveal the cause.
To identify the specific type, doctors order serology tests. A hepatitis B surface antigen test detects active hepatitis B infection, while a hepatitis C antibody test screens for hepatitis C exposure. If autoimmune hepatitis is suspected, additional antibody panels help confirm the diagnosis. Imaging and, occasionally, liver biopsy may be used to assess the degree of scarring.
Long-Term Complications
Chronic hepatitis B and C are the main drivers of serious liver disease worldwide. Without treatment, persistent inflammation can progress to cirrhosis over 10 to 30 years. Once cirrhosis develops, the risk of liver cancer (hepatocellular carcinoma) rises substantially. In patients with cirrhosis from hepatitis B, the annual rate of liver cancer ranges from 0.9 to 5.4 percent. Even without cirrhosis, hepatitis B carries some cancer risk, estimated between 0.01 and 1.4 percent. One-third of all liver cancer deaths globally are attributable to hepatitis B alone.
Hepatitis C follows a similar trajectory but is now curable. Successful antiviral treatment dramatically reduces the risk of cirrhosis, liver failure, and cancer, though people who already have advanced scarring at the time of treatment still need ongoing monitoring.
Treatment Options by Type
Hepatitis A has no specific antiviral treatment. The body clears the virus on its own, and care focuses on rest, hydration, and avoiding alcohol and liver-stressing medications during recovery.
Chronic hepatitis B is managed with antiviral therapy that suppresses the virus and slows liver damage, but a true cure remains elusive for most patients. Treatment is often long-term, sometimes lifelong.
Chronic hepatitis C, by contrast, is now one of the few chronic viral infections that can be cured. Direct-acting antiviral regimens are taken as daily pills for 8 to 12 weeks, with cure rates of 95 to 99 percent. For the small number of patients who don’t respond to a first course, extended or combination regimens still achieve cure rates above 95 percent.
Alcoholic hepatitis requires stopping alcohol completely. In severe cases, hospitalization is necessary. Autoimmune hepatitis is treated with immune-suppressing medications, often for years. In all forms of chronic hepatitis, the goal is the same: reduce inflammation before irreversible scarring takes hold.