Hepatitis is inflammation of the liver which implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. Hepatitis may start and resolve quickly (acute hepatitis), or cause long-term disease (chronic hepatitis). In some instances, progressive liver damage, liver failure, or even liver cancer may result. Hepatitis is acute when it lasts less than six months and chronic when it persists longer.

A group of viruses known as the hepatitis viruses cause most cases of liver damage worldwide. Hepatitis can also be due to toxins (notably alcohol), other infections or from autoimmune process. It may run a subclinical course when the affected person may not feel ill. The patient becomes unwell and symptomatic when the disease impairs liver functions that include, among other things, removal of harmful substances, regulation of blood composition, and production of bile to help digestion.

Hepatitis A

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus. Hepatitis A is one of several types of hepatitis viruses that cause inflammation that affects your liver's ability to function

You're most likely to contract hepatitis A from contaminated food or water or from close contact with someone who's already infected. Mild cases of hepatitis A don't require treatment, and most people who are infected recover completely with no permanent liver damage.

Practicing good hygiene — including washing your hands often — is one of the best ways to protect against hepatitis A. Effective vaccines are available for people who are most at risk.

Hepatitis B

Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, hepatitis B infection becomes chronic, leading to liver failure, liver cancer, or cirrhosis — a condition that causes permanent scarring of the liver.

Most people infected with hepatitis B as adults recover fully, even if their signs and symptoms are severe. Infants and children are much more likely to develop a chronic hepatitis B infection. Although no cure exists for hepatitis B, a vaccine can prevent the disease. If you're already infected, taking certain precautions can help prevent spreading HBV to others.

Hepatitis C

Hepatitis C is an infection caused by a virus that attacks the liver and leads to inflammation. Most people infected with the hepatitis C virus (HCV) have no symptoms. In fact, most people don't know they have the hepatitis C infection until liver damage shows up, decades later, during routine medical tests.

Hepatitis C is one of several hepatitis viruses and is generally considered to be among the most serious of these viruses. Hepatitis C is passed through contact with contaminated blood — most commonly through needles shared during illegal drug use.

Autoimmune Hepatitis

Autoimmune hepatitis is inflammation in your liver that occurs when your body's immune system attacks your liver. Although the cause of autoimmune hepatitis isn't entirely clear, some diseases, toxins and drugs may trigger autoimmune hepatitis in susceptible people, especially women.

Untreated autoimmune hepatitis can lead to scarring of the liver (cirrhosis) and eventually to liver failure. When diagnosed and treated early, however, autoimmune hepatitis often can be controlled with drugs that suppress the immune system.

A liver transplant may be an option when autoimmune hepatitis doesn't respond to drug treatments or when liver disease is advanced.