Hepatitis delta is a serious liver infection that can make people feel very tired, lose their appetite, and notice nausea, belly pain, or yellowing of the skin and eyes. It only affects people who also have hepatitis B, and it can happen as a short-term infection or become long lasting. The early symptoms of hepatitis delta can feel like a bad flu or stomach illness, so some people do not realize the liver is involved at first. Not everyone will have the same experience, but hepatitis delta can lead to cirrhosis, liver failure, and a higher risk of death if liver damage becomes severe. Treatment may include antiviral care such as pegylated interferon or, in some places, bulevirtide, along with close follow-up and sometimes liver transplant for advanced disease.
How many people live with Hepatitis delta?
Worldwide, about 12 million people are estimated to be living with hepatitis delta, also called hepatitis D (WHO, 2024). In the United States, CDC estimates about 640,000 adults are living with long-term hepatitis B, and if about 5% also have hepatitis delta, that suggests roughly 32,000 people may be living with hepatitis delta in the U.S.; this is an estimate, not a direct count (CDC, 2024; WHO, 2024).
Overview
Hepatitis deltaSymptoms
Hepatitis delta often causes tiredness, nausea, belly pain, and yellowing of the skin or eyes. Some people also notice dark urine, poor appetite, or joint aches. Early symptoms of hepatitis delta can feel like the flu.
Outlook and prognosis
Hepatitis delta can be serious, especially if liver damage is already present. With early treatment and regular follow-up, many people can slow liver scarring and lower the risk of liver failure, cirrhosis, and liver cancer.
Causes and risk factors
Hepatitis delta happens only in people with hepatitis B. Risk rises with shared needles, unprotected sex, exposure to infected blood, and living in or traveling from areas where hepatitis delta is more common. Household and birth-related spread can also occur.
Genetic influences
Genetics matter less in hepatitis delta than in many inherited conditions. Your own genes may slightly affect immune response and liver scarring, but the virus strain, hepatitis B status, and access to treatment usually have a bigger effect.
Diagnosis
Hepatitis delta is diagnosed with blood tests that look for hepatitis D infection in someone who also has hepatitis B. The diagnosis of hepatitis delta may also include liver blood work and sometimes ultrasound imaging.
Treatment and drugs
Hepatitis delta is usually treated with antiviral medicine, most often peginterferon alfa. Some people may also be offered bulevirtide where available, and careful monitoring is important because managing hepatitis B at the same time is essential.
Symptoms
Hepatitis delta can be easy to miss at first because some people feel nothing at all, while others feel like they have a bad flu or stomach bug. Day to day, it can feel like low energy, poor appetite, nausea, or a dull ache under the right ribs. The early symptoms of hepatitis delta often overlap with other liver problems, but this infection can become severe more quickly in people who also have hepatitis B.
Some people with hepatitis delta do not notice any symptoms at first. Even so, the liver can still be inflamed and damaged while you feel mostly normal.
Tiredness is common and can feel heavier than an ordinary busy day. Work, exercise, or simple errands may take more effort than usual.
Loss of appetite, nausea, and sometimes vomiting can make meals hard to get through. Over time, this can lead to weakness or unplanned weight loss.
Early symptoms of hepatitis delta can include a low fever, body aches, joint pain, and a general flulike feeling. These symptoms are easy to mistake for a short-term infection at first.
How people usually first notice Hepatitis delta?
Hepatitis delta often enters the picture quietly, and many people first notice it when tiredness, nausea, loss of appetite, or pain on the right side of the upper belly starts to feel hard to ignore. As the liver becomes more inflamed, darker urine, pale stools, yellowing of the skin or eyes, and unexplained itching can appear, though some people have few symptoms at first and only learn something is wrong after abnormal liver blood tests. Because hepatitis delta only occurs in people who also have hepatitis B, a sudden worsening of symptoms in someone living with hepatitis B is one of the most important first warning signs.
Types of Hepatitis delta
Hepatitis delta can show up in two main ways, and the difference matters in day-to-day life because it affects how quickly people get sick and how likely the infection is to last. In practice, the main types of hepatitis delta are based on whether the delta virus arrives at the same time as hepatitis B or is added later in someone who already has hepatitis B. Symptoms do not always look very different at first, but the course of illness and the risk of serious liver damage can be quite different.
Coinfection
This happens when hepatitis B and hepatitis delta are caught at the same time. People may develop sudden symptoms of acute hepatitis, such as fatigue, nausea, belly pain, dark urine, or yellowing of the skin and eyes, and some have no symptoms at all. It can be severe, but many clear both infections and do not go on to chronic hepatitis delta.
Superinfection
This happens when someone who already has long-term hepatitis B later gets hepatitis delta. Symptoms may come on as a sudden worsening, with stronger tiredness, jaundice, swelling, or other signs that the liver is under stress. This form is more likely to become chronic and usually carries a higher risk of faster liver scarring and liver failure.
Can I slow down the onset of symptoms?
Not in a reliable way once hepatitis delta has started, although avoiding alcohol, keeping a healthy weight, and getting regular care for both hepatitis B and hepatitis delta may help protect the liver and may slow damage in some people. Because hepatitis delta only happens in people who also have hepatitis B, the clearest proven way to reduce the chance of ever developing hepatitis delta is to prevent hepatitis B with vaccination if you have not already had it; for people already infected, regular follow-up can help catch liver problems early, but it does not guarantee symptoms can be delayed. These steps may lower risk or slow liver injury, but they cannot promise prevention, and staying closely connected with your care team is still worthwhile.
What genetics can tell you about symptoms
For hepatitis delta, genetics can play some role, but they do not clearly predict exactly which symptoms someone will have day to day. Differences in the virus itself, and possibly in a person’s immune-response genes, may affect how strongly the liver is inflamed, how severe the illness becomes, and how quickly liver damage develops, but these links are still limited and are not used much to forecast symptoms for one individual. In practice, symptoms and timing are shaped more by how active the infection is, whether hepatitis B is also present, and how much liver injury has already occurred.
Causes and risk factors
Hepatitis delta happens when the hepatitis D virus enters the body, and it can only infect people who already have hepatitis B. The biggest risk is contact with infected blood, such as through shared needles, nonsterile tattoo or piercing equipment, or needlestick injuries. Sex without condoms can also spread it, and the risk is higher for many living with hepatitis B or in places where hepatitis delta is more common. Genes are not a main cause of hepatitis delta, but your immune health and whether hepatitis B is long term can affect how severe it becomes. Knowing the risks can help you feel more in control, and the main lifestyle-related risk factors for hepatitis delta are injecting drugs and other situations that increase blood or sexual exposure.
What are the most common causes or risk factors?
The main cause of hepatitis delta is infection with the hepatitis delta virus, but this virus can only infect people who also have hepatitis B, either because they already have it or catch both around the same time. The biggest risk factors are contact with infected blood or body fluids, especially from sharing needles or other drug equipment, having sex without condoms, getting unsafe tattoos or piercings, or being born to a mother with hepatitis B. Living in or coming from places where hepatitis B and hepatitis delta are more common, and not being vaccinated against hepatitis B, also raise the risk; inherited genetic factors are not a main known cause.
Environmental and biological risk factors
Hepatitis delta is a liver infection that can only happen in someone who also has hepatitis B. Doctors often group risks into internal (biological) and external (environmental). When people ask who is at risk for hepatitis delta infection, the biggest factors are having hepatitis B and being exposed to infected blood or body fluids.
Hepatitis delta cannot occur unless hepatitis B is already present. Many living with long-term hepatitis B have the clearest biological risk for hepatitis delta.
Living in communities where hepatitis delta is more common raises the chance of exposure. This is more likely in places where hepatitis B is also widespread and blood-safety measures may be limited.
Reused needles, poorly sterilized equipment, or unscreened blood products can spread hepatitis delta. This risk is higher where infection-control and blood screening are not consistent.
People receiving long-term dialysis have repeated contact with blood-handling equipment and procedures. Strict infection-control lowers the risk, but exposure can happen if hepatitis B and delta are present in the unit.
Genetic risk factors
Hepatitis delta is not usually passed down through families the way inherited disorders are. Instead, the biology behind it involves the hepatitis delta virus, along with inherited differences that may shape how easily the virus enters liver cells or how strongly the immune system reacts. Risk is not destiny—it varies widely between individuals. Researchers are still learning which genetic risk factors for hepatitis delta matter most, and no single genetic factor can predict who will become severely ill.
Not inherited: Hepatitis delta is not known to be caused by a single inherited gene change. In most cases, family history alone does not mean someone will develop hepatitis delta.
Immune genes: Small inherited differences in immune system genes may affect how well the body controls hepatitis delta. These differences may influence whether infection clears, becomes long lasting, or causes more liver inflammation.
Liver receptor gene: The virus uses a receptor on liver cells to get inside, and rare inherited changes in the gene for this receptor may alter how easily infection takes hold. These changes are uncommon, and their effects can differ between populations.
Viral genotype: Different genetic types of the hepatitis delta virus can lead to different patterns of illness. Some types are linked with a more aggressive course, while others are often milder, although this varies by region and by the person affected.
Lifestyle risk factors
Hepatitis delta is strongly tied to everyday behaviors because the virus spreads only in people who already have hepatitis B. The main lifestyle risk factors for hepatitis delta involve exposure to blood or body fluids and habits that speed up liver damage after infection. Diet and exercise do not usually determine whether someone catches the virus, but alcohol use, substance use, and metabolic health can affect how liver disease progresses.
Sharing needles, syringes, cookers, or other drug equipment can spread hepatitis B and delta through blood exposure. This is one of the most important behavior-related ways hepatitis delta is acquired.
Sex without condoms, especially with multiple partners or during rough sex that causes bleeding, can raise the chance of hepatitis B transmission and therefore hepatitis delta. The risk is higher if a partner has hepatitis B and does not know it.
Sharing razors, toothbrushes, nail tools, or anything that may carry small amounts of blood can increase transmission risk. These exposures are easy to overlook but still matter in household or close-contact settings.
Tattoos, piercings, or informal cosmetic injections done with poorly sterilized equipment can spread blood-borne viruses. Choosing licensed settings with strict infection control lowers this risk.
Risk prevention
Hepatitis delta is usually preventable because this virus can only infect people who also have hepatitis B. In day-to-day life, that means the most effective protection is avoiding hepatitis B in the first place and lowering exposure to blood or body fluids that can spread infection. Prevention can mean both medical steps, like vaccines, and lifestyle steps, like exercise.
There is no separate hepatitis delta vaccine, but the hepatitis B vaccine prevents most hepatitis delta infections by blocking the virus hepatitis delta needs to survive. This is the single most effective answer to how to prevent hepatitis delta infection.
Using condoms and limiting exposure to blood and sexual fluids can lower the risk of catching hepatitis B and, in turn, hepatitis delta. This matters especially if you have a new partner, multiple partners, or a partner with hepatitis B.
Sharing needles, syringes, or other drug equipment can spread hepatitis B very efficiently. Using new, sterile equipment every time and getting support for substance use can sharply reduce risk.
Do not share razors, toothbrushes, nail tools, or anything that may have small amounts of blood on it. Tattooing, piercing, or medical care should be done only with properly sterilized or single-use equipment.
Can you prevent Hepatitis delta?
Often, yes, hepatitis delta can be prevented, because it only affects people who also have hepatitis B. There is no separate hepatitis delta vaccine, but getting the hepatitis B vaccine, not sharing needles or other items that may have blood on them, and using condoms can lower the risk. If someone already has hepatitis B, these steps can still help reduce the chance of getting hepatitis delta, but they cannot remove the risk completely.
Transmission
Hepatitis delta, also called hepatitis D, spreads when blood or certain body fluids from someone with the virus enter another person’s body. It most often happens through sharing needles or other drug equipment, unsterile tattoo or piercing tools, needlestick injuries, and sometimes through sex or from parent to baby at birth.
A key point in how hepatitis delta is spread is that it can only infect people who also have hepatitis B, because the delta virus needs hepatitis B to survive and spread. Hepatitis delta is not passed by hugging, coughing, sharing food, or other everyday contact, but it can be quite infectious through direct blood exposure.
When to test your genes
For hepatitis delta, genetic testing is not part of early detection or routine care. What matters is blood testing if you have hepatitis B, abnormal liver tests, or risk factors such as injection drug use or exposure to infected blood. In some cases, viral genotyping may help specialists guide treatment.
Diagnosis
Hepatitis delta is usually suspected when someone already has hepatitis B and then has more severe liver inflammation than expected, new symptoms, or a sudden worsening after seeming stable. You might notice fatigue that does not let up, nausea, dark urine, belly discomfort, or yellowing of the eyes and skin, which can prompt testing. Doctors usually begin with blood tests, because the diagnosis of hepatitis delta depends on showing both hepatitis B infection and signs of the delta virus.
A clinician asks about current symptoms, past hepatitis B results, travel, sexual exposure, injection drug use, and household or blood contact risks. A detailed family and health history can help, but hepatitis delta is diagnosed mainly from infection risks and lab findings rather than family patterns.
Liver blood tests can show inflammation or liver stress, including high enzymes and sometimes changes in bilirubin or clotting. These tests cannot confirm hepatitis delta on their own, but they show how much the liver may be affected.
A blood test can look for antibodies to hepatitis delta, which shows the immune system has reacted to the virus. This is often an early step in how hepatitis delta is diagnosed, especially in people who already test positive for hepatitis B surface antigen.
If hepatitis delta is suspected, a molecular test looks for HDV RNA, the virus itself, in the blood. This confirms active infection and can also help track how the infection responds over time.
How is Hepatitis delta diagnosed?
Hepatitis delta is usually diagnosed with blood tests in someone who already has hepatitis B, looking for signs that the hepatitis delta virus is present and whether it is still active in the blood. Doctors also check liver blood tests to see how well the liver is working and may use an ultrasound to look for liver damage. In some cases, testing may be repeated if the first results are not clear or if doctors need to track how active the infection is over time.
Stages of Hepatitis delta
Hepatitis delta does not have defined progression stages. This is because it is usually described by how active the infection is and how much liver damage it has caused, rather than by a set step-by-step course. Doctors usually start with a conversation about symptoms, risk factors, and whether you already have hepatitis B, then confirm hepatitis delta with blood tests that look for the virus or your body’s response to it. To understand how hepatitis delta is diagnosed and monitored over time, your doctor may also check liver enzyme levels and sometimes use imaging or a liver stiffness test to look for scarring.
Outlook and prognosis
The outlook for people with hepatitis delta is generally worse than for hepatitis B alone, because the infection often causes faster progression to cirrhosis, liver failure, and liver cancer. In chronic hepatitis delta, a substantial proportion of patients develop cirrhosis within a few years, especially if the disease is untreated or if there is ongoing alcohol use or other liver injury. Mortality is mainly related to complications of advanced liver disease, including decompensated cirrhosis and hepatocellular carcinoma, and the risk of liver-related death is higher than in chronic hepatitis B without delta infection. Prognosis is better when the virus is detected early, monitored closely, and treated effectively, with suppression or clearance of hepatitis B surface antigen offering the best long-term outcome. People who develop acute hepatitis delta on top of existing hepatitis B can become severely ill, and in rare cases fulminant hepatitis can be fatal. Liver transplantation can be lifesaving for end-stage disease, and widespread hepatitis B vaccination remains the most effective way to prevent hepatitis delta and its complications.
Long-term effects
For many people, hepatitis delta can put lasting strain on the liver, especially if the infection is not brought under control. The long-term effects of hepatitis delta depend on how much liver damage builds up over time and whether cirrhosis develops. Thinking about the long-term effects helps explain why some people stay stable for years while others become sick more quickly. In general, outlook is worse when hepatitis delta causes ongoing inflammation alongside hepatitis B.
Ongoing liver inflammation can lead to scarring, known as cirrhosis. This may happen faster in hepatitis delta than in hepatitis B alone.
Severe scarring can make it hard for the liver to do its usual work, such as clearing toxins and helping with blood clotting. Over time, this can lead to liver failure and serious illness.
People with hepatitis delta have a higher risk of liver cancer, especially if cirrhosis is present. This is why doctors often monitor the liver over time, even when day-to-day symptoms seem mild.
Advanced liver disease can cause swelling in the belly or legs from fluid retention. Many living with hepatitis delta may notice tighter clothes, shoes that suddenly feel snug, or a heavy, bloated feeling.
How is it to live with Hepatitis delta?
Living with hepatitis delta can feel unpredictable, because energy may dip, nausea or right-sided belly discomfort can come and go, and many people also carry the emotional weight of having a long-term liver infection that needs close follow-up. In daily life, this often means regular blood tests and liver checkups, being careful with alcohol and medicines that can strain the liver, and pacing yourself during flares of fatigue while still remembering that some people have few symptoms for long stretches. For the people around you, the biggest practical issue is prevention and support: hepatitis delta spreads only in people who also have hepatitis B, so household contact is usually safe with normal social contact, but partners and close contacts should make sure they are protected against hepatitis B and avoid exposure to blood while offering steady, nonjudgmental support.
Treatment and drugs
Hepatitis delta is treated by controlling the infection, protecting the liver, and also managing hepatitis B, because the delta virus depends on hepatitis B to survive. Treatment often looks different for each person, but the main drug used in some countries is bulevirtide, and some people may also be offered pegylated interferon, an older medicine that helps the immune system fight the virus. Not every treatment works the same way for every person, and doctors usually monitor blood tests and liver health closely to see whether treatment is helping and whether side effects are becoming a problem. Alongside medical treatment, lifestyle choices play a role, such as avoiding alcohol and checking all medicines and supplements with your doctor so the liver is not put under extra strain. If hepatitis delta has already caused severe liver damage, treatment may focus on complications of cirrhosis, and for some people a liver transplant becomes the best option.
Can you cure Hepatitis delta?
There is no sure cure for hepatitis delta right now. Treatment can help lower the virus, slow or limit liver damage, and reduce the risk of serious problems like liver scarring or liver failure, but it does not work the same way for everyone. Many living with hepatitis delta need ongoing care, including medicines, regular liver checks, and treatment for hepatitis B as well.
Non-drug treatment
Living with hepatitis delta often means caring for your liver day by day, not just treating lab results. For many, treatment begins not at the pharmacy, but with supportive care, regular checkups, and habits that lower further liver strain; these are central parts of non-drug treatment for hepatitis delta. Many living with hepatitis delta also need ongoing monitoring so problems such as scarring, fluid buildup, or liver cancer can be caught early. The best plan depends on how much liver damage is already present and whether cirrhosis has developed.
Regular follow-up with a liver specialist helps track how active hepatitis delta is and how well your liver is coping. Visits often include blood tests, imaging, and checks for signs of worsening scarring or liver failure.
Avoiding alcohol is one of the most important non-drug steps because alcohol can speed up liver damage. For many, this can mean skipping social drinks entirely, even when symptoms are mild.
Many people with hepatitis delta need a careful review of prescription drugs, over-the-counter pain relievers, and herbal supplements. Some products can stress the liver, so it is safest to check before starting anything new.
Eating regularly and staying active can help protect strength, energy, and overall health while living with hepatitis delta. If appetite is poor, nausea is frequent, or weight is dropping, a dietitian can help build a plan that feels realistic.
Your genes may have an impact on how drugs work for you
For hepatitis delta, your genes do not usually play a major role in choosing treatment, and genetic testing is not a routine part of care. Even so, natural differences in how the body handles medicine can sometimes affect how well treatment works or how strongly side effects are felt, but for many living with hepatitis delta, things like how much liver damage is already present and how active the infection is matter more. In other words, doctors usually base treatment decisions on the liver, the virus, and overall health rather than on inherited DNA differences.
Pharmacological treatments
Treatment for hepatitis delta is more limited than for many other liver infections, and the best plan depends on how active the virus is and how much liver damage is already present. The main drug options are peginterferon alfa and, in some countries, bulevirtide; some people also need hepatitis B medicines because hepatitis delta can only exist alongside hepatitis B. Not everyone responds to the same medication in the same way, so follow-up blood tests are a routine part of care.
Peginterferon alfa is an immune-based medicine given by injection, usually for a limited course such as about 48 weeks. It can lower hepatitis delta virus levels in some people, but it does not work for everyone and side effects like flu-like symptoms, low mood, and low blood counts can limit use.
Bulevirtide is a newer hepatitis delta treatment that blocks the virus from entering liver cells. It is approved in parts of Europe and some other regions, but availability in the United States may differ, and it is often used with close liver and virus monitoring.
Tenofovir and entecavir treat hepatitis B rather than hepatitis delta directly, but they are often important when hepatitis B virus is also active. For many living with hepatitis delta, controlling hepatitis B can help protect the liver even if these drugs do not clear the delta virus itself.
In some cases, medicines are combined for a stronger effect, such as bulevirtide with peginterferon alfa in selected people. Combination treatment for hepatitis delta may improve virus control, but it also needs careful monitoring for side effects and liver function changes.
Genetic influences
If hepatitis delta affects you or someone close to you, it is understandable to wonder whether it is something that runs in families. Genetics is only one piece of the puzzle, but hepatitis delta is mainly caused by infection with the hepatitis D virus in someone who already has hepatitis B, not by an inherited gene change. In other words, family members usually share risk because of shared exposure or because hepatitis B can pass through families, especially around birth, rather than because hepatitis delta itself is a genetic condition. Researchers do think that small inherited differences in the immune system may help explain why some people with hepatitis delta get more liver inflammation, scarring, or cirrhosis than others. Even so, genetic testing is not part of the usual workup, and the main focus stays on testing for hepatitis B and hepatitis delta, checking liver health, and understanding risk factors for hepatitis delta. For many living with hepatitis delta, the most useful family question is not "Which gene caused this?" but whether close relatives should be screened or vaccinated for hepatitis B.
Is Hepatitis delta genetic?
Genetics matter less in hepatitis delta than in many inherited conditions. Your own genes may slightly affect immune response and liver scarring, but the virus strain, hepatitis B status, and access to treatment usually have a bigger effect.
Having a genetic risk is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal part of being human. Most of these variants do not directly affect health and simply reflect natural differences among people. For many genes, having a variant associated with a condition suggests a possible link rather than a certain diagnosis, especially when several genes and environmental factors are involved. In some situations, however, a single well-understood variant in a particular gene can be enough to confirm a diagnosis.
Pharmacogenetics—how genetics influence drug effects
For people with hepatitis delta, genetics are not yet a major part of choosing treatment in everyday care. At this point, there is no widely used genetic test for hepatitis delta treatment that can reliably tell doctors which medicine will work best or who will have side effects. Researchers are studying whether small differences in a person’s immune-related genes, and differences in the virus itself, may affect response to interferon-based treatment, but these findings are not strong enough to guide routine prescribing. In practice, doctors usually base hepatitis delta treatment more on how much liver damage is present, whether hepatitis B is also active, and other health factors such as pregnancy, kidney function, and possible drug interactions. Genetics is only one factor, and for many living with hepatitis delta, newer treatments are chosen and monitored based mainly on liver tests and overall health rather than DNA results.
Interactions with other conditions
Hepatitis delta rarely occurs on its own because it depends on hepatitis B to infect the liver, so many living with hepatitis delta are also dealing with chronic hepatitis B at the same time. Doctors call it a comorbidity when two conditions occur together. Day to day, this can mean liver symptoms become more severe, with a higher chance of ongoing inflammation, scarring of the liver, cirrhosis, and liver failure than with hepatitis B alone. If someone already has another liver problem, such as fatty liver disease or hepatitis C, the liver may have less reserve, and tiredness, abdominal swelling, or jaundice can become harder to sort out. People with hepatitis delta may also need extra care if they have HIV, are taking medicines that affect the liver, or drink alcohol regularly, because these factors can add to liver stress and complicate treatment choices. If you are wondering about the early symptoms of hepatitis delta, it is especially important to talk with your doctor about other liver conditions and infections, since they can change both how the illness feels and how urgently it needs treatment.
How genes can cause diseases
Humans have more than 20,000 genes, each carrying out one or a few specific functions in the body. One gene instructs the body to digest lactose from milk, another tells the body how to build strong bones and another prevents the body's cells from beginning to multiply uncontrollably and developing into cancer. As all of these genes combined are the building instructions for our body, a defect in one of these genes can have severe health consequences.
Through decades of genetic research, we know the genetic code of any healthy/functional human gene. We have also identified that in certain positions on a gene, some individuals may have a different genetic letter from the one you have. We call these hotspots "Genetic Variations" or "Variants" in short. In many cases, studies have been able to show that having the genetic letter "G" in the position makes you healthy, but having the letter "A" in the same position disrupts the gene function and causes a disease. Genopedia allows you to view these variants in genes and summarizes all that we know from scientific research, which genetic letters (Genotype) have good or bad consequences on your health or on your traits.
What other conditions can cause similar symptoms to Hepatitis delta?
Other liver problems can look a lot like hepatitis delta, especially hepatitis B on its own, hepatitis A, hepatitis C, and sometimes hepatitis E. Doctors may also consider fatty liver disease, liver irritation from alcohol or medicines, and blocked bile flow from gallstones, because these can also cause tiredness, nausea, pain on the right side of the belly, dark urine, and yellowing of the skin or eyes.
History
Long before today’s lab tests, doctors noticed that some people with hepatitis became much sicker than expected, with faster liver damage and more severe illness. In recent decades, awareness has grown that hepatitis delta is a distinct infection linked to hepatitis B, rather than simply a more intense form of hepatitis on its own. That shift mattered in everyday care, because it helped explain why someone might seem stable with hepatitis B for years and then suddenly develop worsening jaundice, fatigue, or signs of liver disease.
The virus behind hepatitis delta was first recognized in the 1970s, when researchers found an unusual marker in some people already living with hepatitis B. From these first observations, scientists gradually learned that hepatitis delta depends on hepatitis B to spread and survive in the body. As testing improved, doctors began to separate hepatitis delta from other causes of hepatitis and to understand why it could lead to cirrhosis and liver failure more quickly in some people.
Over time, public health efforts such as blood screening, safer injections, and hepatitis B vaccination changed the picture in many countries. In some regions, hepatitis delta became less common, while in others it remained an important cause of serious liver disease, especially where hepatitis B is more widespread. The way the condition was viewed also changed as better studies showed that many living with hepatitis delta had been underdiagnosed for years, partly because symptoms can overlap with other liver problems.
Today, the history of hepatitis delta is still unfolding. Researchers now have a clearer view of who should be tested, how infection patterns differ around the world, and why early symptoms of hepatitis delta can be easy to miss. Knowing this history helps explain why modern care focuses not only on treating liver disease, but also on finding hepatitis delta sooner in people who already have hepatitis B.