Hepatitis B symptoms typically include fatigue, abdominal pain, dark urine, and yellowing of the skin or eyes. However, most people don’t experience any symptoms when first infected, which is one of the reasons this virus spreads so easily. When symptoms do appear, they usually show up about 90 days after exposure, though the range spans from 60 to 150 days.
Acute Symptoms in Adults
Acute hepatitis B refers to the first six months after infection. Adults are more likely than children to develop noticeable symptoms during this phase, though many still have none at all. When symptoms do appear, they can include:
- Abdominal pain, particularly in the upper right area near the liver
- Dark urine, often described as tea- or cola-colored
- Fever
- Joint pain
- Loss of appetite
- Nausea and vomiting
- Weakness and extreme fatigue
- Jaundice, a yellowing of the whites of the eyes and the skin
Jaundice can be harder to spot on darker skin tones. Checking the whites of the eyes or the inside of the mouth is often more reliable than looking at the skin alone. These symptoms can range from mild to severe and typically last several weeks, though fatigue sometimes lingers longer than other symptoms resolve.
The good news for adults: roughly 95% of people who are infected as adults recover completely and clear the virus on their own within six months.
Why Many People Have No Symptoms
One of the most important things to understand about hepatitis B is that the absence of symptoms doesn’t mean the absence of infection. Most people feel nothing when newly infected. This is especially true for young children and infants, who are almost always asymptomatic. That silent period is dangerous because the virus can still be transmitted to others, and in children, it’s far more likely to become a lifelong infection.
This is why screening matters. If you have risk factors (born in a region where hepatitis B is common, had unprotected sexual contact with an infected person, shared needles, or were born to a mother with hepatitis B), a blood test is the only reliable way to know your status.
Symptoms in Infants and Children
Children under 5 are typically asymptomatic during acute infection. This sounds reassuring, but it’s actually the opposite. Infants who contract hepatitis B, usually during birth from an infected mother, have a 90% chance of developing chronic infection. Children infected between ages 1 and 5 have about a 30% chance. Compare that to the roughly 5% chronic rate in adults, and it’s clear why newborn screening and vaccination at birth are standard practice.
Because these young children rarely show symptoms, the infection can go undetected for years or even decades, quietly damaging the liver before anyone knows it’s there.
Chronic Hepatitis B Symptoms
If the virus isn’t cleared within six months, the infection becomes chronic. Chronic hepatitis B can remain silent for 20 or 30 years while slowly causing liver damage. When symptoms eventually surface, they often overlap with the acute symptoms but reflect more advanced liver problems:
- Persistent fatigue that doesn’t improve with rest
- Abdominal pain or a feeling of fullness in the upper right side
- Joint or muscle aches
- Loss of appetite and unintended weight loss
- Jaundice that comes and goes or worsens over time
- Spider-like blood vessels visible on the skin
- Swelling in the abdomen or legs from fluid buildup
These later symptoms often signal that the liver is scarred (cirrhosis) or that liver function is declining. By the time chronic hepatitis B causes noticeable symptoms, significant damage may already be present, which is why people with chronic infection need regular monitoring even when they feel fine.
Warning Signs of Severe Liver Failure
In rare cases, acute hepatitis B can progress to fulminant hepatitis, a rapid and life-threatening form of liver failure. This affects a small percentage of people but requires emergency medical attention. The warning signs develop and worsen quickly, often over days to weeks:
- New or rapidly worsening jaundice
- Confusion, disorientation, or sudden personality changes (signs that toxins are building up in the brain because the liver can’t filter them)
- Unexplained bleeding or bruising, such as bleeding gums or nosebleeds that won’t stop
- Severe abdominal swelling
- Extreme drowsiness progressing toward unresponsiveness
Fulminant hepatitis can progress from confusion to coma over a period of several days to several weeks. If someone with known or suspected hepatitis B develops sudden mental changes or unexplained bleeding, that’s a medical emergency.
How Hepatitis B Is Confirmed
Because symptoms alone can’t distinguish hepatitis B from other liver conditions (or may be absent entirely), diagnosis relies on blood tests. The key test looks for a protein on the surface of the virus called hepatitis B surface antigen, or HBsAg. A positive result means the virus is currently present in your blood.
Additional blood markers help determine whether the infection is new (acute), long-standing (chronic), or already resolved. For example, having antibodies against the surface antigen without the antigen itself typically means you’ve recovered from a past infection and are now immune, or that you’ve been vaccinated. Your doctor can interpret the combination of markers to give you a clear picture of where things stand.
If you’re diagnosed with chronic hepatitis B, ongoing blood tests and periodic imaging of the liver help track whether the virus is actively replicating and whether any liver damage is developing. Many people with chronic infection live normal lives with monitoring and, when needed, antiviral treatment that suppresses the virus and protects the liver from further harm.