What Causes Jaundice In Adults And Newborns?

Jaundice is not a disease itself but a visible sign of an underlying condition. It happens when bilirubin, a yellow waste product from the normal breakdown of red blood cells, builds up in the blood and deposits in the skin and the whites of the eyes. In newborns, the cause is usually a normal, temporary adjustment as the liver matures. In adults, jaundice almost always signals a problem with the liver, the bile ducts, or the blood itself, and it requires medical evaluation.

What Is Bilirubin and Why Does It Cause Yellowing?

Red blood cells live for about 120 days. When they get old, they break down, and hemoglobin inside them is converted into bilirubin. This bilirubin is unconjugated, meaning it is not water-soluble. It travels through the blood to the liver.

The liver processes this bilirubin, attaching a sugar molecule to make it water-soluble. This is called conjugated bilirubin. The liver then sends it into bile, which flows into the intestine. Most of it leaves the body in stool. That is why stool is brown.

Jaundice appears when any step in this process breaks down. Too much bilirubin is produced. The liver cannot process it fast enough. Or the bile cannot drain properly. When bilirubin levels rise, the yellow pigment becomes visible in the skin, eyes, and mucous membranes.

What Causes Jaundice In Adults And Newborns Differently

The causes of jaundice in adults and newborns are almost entirely different. They share the same yellow pigment but not the same disease process. Understanding the difference matters because the urgency and treatment are distinct.

In newborns, jaundice is most often physiological. It occurs because newborns produce more bilirubin than adults, and their immature livers process it less efficiently. This typically appears on the second or third day of life, peaks around day five, and resolves within one to two weeks. It is normal and usually harmless.

In adults, jaundice is never normal. It always indicates an underlying medical condition that needs investigation. The causes fall into three broad categories: problems before the liver, in the liver, or after the liver.

Pre-Hepatic Jaundice: When Red Blood Cells Break Down Too Fast

Pre-hepatic jaundice happens before bilirubin reaches the liver. The body is destroying red blood cells faster than usual, producing more bilirubin than the liver can handle. This is called hemolysis.

Common causes include inherited conditions like sickle cell disease, spherocytosis, and glucose-6-phosphate dehydrogenase deficiency. Some autoimmune disorders and certain medications can also trigger hemolysis.

Because the liver is healthy but overwhelmed, the bilirubin in the blood is unconjugated. The stool remains normally colored. In fact, stool may be darker than usual because more bilirubin is being processed and excreted.

Hepatic Jaundice: When the Liver Itself Is Damaged

Hepatic jaundice means the liver cells themselves are not functioning properly. They either cannot take up bilirubin, cannot process it, or cannot excrete it into bile. This is the most common category of adult jaundice.

Viral hepatitis is a leading cause. Hepatitis A, B, and C can all inflame the liver and impair its function. Hepatitis A is usually foodborne and resolves on its own. Hepatitis B and C can become chronic and cause lasting liver damage.

Alcohol-related liver disease is another major cause. It progresses from fatty liver to alcoholic hepatitis to cirrhosis. Jaundice often appears in the later stages when liver function is significantly impaired.

Non-alcoholic fatty liver disease is increasingly common, especially in people with obesity, diabetes, or metabolic syndrome. It can progress to cirrhosis and jaundice, though this takes years or decades.

Medications can also cause hepatic jaundice. Acetaminophen in high doses is the most well-known example. Other drugs, including certain antibiotics, anti-seizure medications, and herbal supplements, can damage liver cells.

Autoimmune hepatitis occurs when the immune system attacks liver cells. It is more common in women and can be treated with immunosuppressive medications.

Cirrhosis from any cause — alcohol, hepatitis, fatty liver, or other conditions — can eventually lead to jaundice as scar tissue replaces functioning liver tissue.

Post-Hepatic Jaundice: When Bile Cannot Drain

Post-hepatic jaundice, also called obstructive jaundice, happens after the liver has processed bilirubin. The problem is that bile cannot flow out of the liver into the intestine. This causes conjugated bilirubin to back up into the blood.

Gallstones are the most common cause of bile duct obstruction. A stone can block the common bile duct, preventing bile from draining. This often causes sudden pain in the upper right abdomen, nausea, and jaundice.

Pancreatic cancer is a serious cause of obstructive jaundice. Tumors in the head of the pancreas can compress the bile duct. This is one reason adults with new jaundice need prompt imaging studies.

Other causes include bile duct strictures, which are narrowings from prior surgery or inflammation, and bile duct cancers. In some cases, parasites or enlarged lymph nodes can compress the bile duct.

With obstructive jaundice, stool often becomes pale or clay-colored because bilirubin is not reaching the intestine. Urine may become dark brown because conjugated bilirubin is water-soluble and passes into the urine.

Newborn Jaundice: When to Worry

Most newborn jaundice is harmless and resolves on its own. But there are serious causes that require treatment. The key is distinguishing between the two.

Physiological jaundice appears after 24 hours of life, peaks around day three to five, and resolves by day fourteen. The baby is otherwise healthy, feeding well, and active. This type does not need treatment beyond ensuring adequate feeding and monitoring.

Breastfeeding jaundice occurs in the first week when a baby is not getting enough breast milk. This is not a problem with the milk itself but with milk intake. Poor feeding leads to dehydration and reduced bowel movements, which slows bilirubin excretion.

Breast milk jaundice appears after the first week and can last several weeks. It is thought to be related to substances in breast milk that affect bilirubin processing. It is generally harmless and resolves on its own, though it can persist longer than physiological jaundice.

Pathological jaundice is different. It appears within the first 24 hours of life, involves rapidly rising bilirubin levels, or lasts longer than two weeks. Causes include blood type incompatibility, such as Rh or ABO incompatibility, which causes rapid red blood cell breakdown. Other causes include G6PD deficiency, sepsis, and biliary atresia, a condition where bile ducts are blocked or absent.

The main concern with severe newborn jaundice is kernicterus. This is a type of brain damage caused by very high bilirubin levels. It is rare when jaundice is monitored and treated appropriately. Treatment involves phototherapy, where blue light helps break down bilirubin in the skin, and in severe cases, exchange transfusion.

Symptoms That Accompany Jaundice in Adults

Jaundice itself is a symptom, not a diagnosis. The symptoms that accompany it help identify the cause.

Dark urine and pale stools suggest obstructive jaundice. Itchy skin is also common with cholestasis, where bile flow is impaired. This itch can be severe and is caused by substances that build up in the blood when bile cannot drain.

Nausea, vomiting, and poor appetite are common with hepatitis. Fever may accompany acute infections. Pain in the upper right abdomen suggests gallbladder or bile duct issues. Weight loss and loss of appetite may indicate cancer or chronic liver disease.

Confusion, sleepiness, or personality changes in someone with jaundice are alarming. These may indicate hepatic encephalopathy, a serious complication of advanced liver disease. This requires immediate medical attention.

How Doctors Determine the Cause

Doctors start with blood tests. A complete blood count shows whether red blood cells are being destroyed. Liver function tests measure bilirubin, liver enzymes, and proteins. These help distinguish between pre-hepatic, hepatic, and post-hepatic causes.

Imaging is usually the next step. An ultrasound of the abdomen is often the first test because it can show gallstones, bile duct dilation, and liver structure. CT scans and MRIs provide more detail. MRCP, a specialized MRI of the bile ducts, is particularly useful for evaluating obstruction.

If imaging and blood tests do not provide a clear answer, a liver biopsy may be needed. This involves taking a small sample of liver tissue to examine under a microscope. It can diagnose conditions like autoimmune hepatitis, certain drug reactions, and some metabolic disorders.

Treatment Depends Entirely on the Cause

There is no single treatment for jaundice. Treating the underlying cause is the only effective approach.

For gallstones blocking the bile duct, endoscopic retrograde cholangiopancreatography, or ERCP, can remove the stone. This procedure involves passing a scope through the mouth into the bile duct. If the obstruction is from a tumor, surgery or stenting may be needed.

Viral hepatitis is treated based on the specific virus. Hepatitis A is supportive care. Hepatitis B may involve antiviral medications. Hepatitis C is treated with direct-acting antiviral drugs that cure most cases.

Alcohol-related liver disease requires stopping alcohol completely. Medication-induced jaundice requires stopping the offending drug. Autoimmune hepatitis is treated with corticosteroids and immunosuppressants.

Newborn jaundice is treated with phototherapy when bilirubin levels exceed certain thresholds. The baby lies under blue lights that convert bilirubin into a form that can be excreted in urine and stool. In severe cases, an exchange transfusion replaces the baby’s blood with donor blood to rapidly lower bilirubin levels.