Primary biliary cholangitis (PBC, formerly known as primary biliary cirrhosis) and primary sclerosing cholangitis (PSC) may sound similar, but there are some key differences between these two liver diseases.

PBC and PSC are considered primary diseases — they aren’t caused by an underlying liver condition. They’re also autoimmune diseases, which happen when the body’s immune system mistakenly attacks its own tissues. Additionally, both conditions cause inflamed bile ducts in the liver that disrupt the organ’s normal functioning. However, the extent of damage they cause, who they affect, and their available treatments aren’t quite the same.

PBC and PSC are cholestatic liver diseases, which means they affect the flow of bile through the liver. Bile is the fluid that helps the body digest fats and remove toxins. It’s made in the liver and stored in the gallbladder. Bile ducts are tubes that help bile flow from the liver to the gallbladder and small intestine. When these passageways get damaged, it can cause symptoms throughout the body.

Here’s how to make sense of PBC and PSC, two related but distinct diagnoses.

1. The Location of Each Liver Disease

PBC attacks the small bile ducts within the liver. PSC is more widespread and may extend to bile ducts outside the liver. The terms for these bile ducts are “intrahepatic” (inside the liver) and “extrahepatic” (outside the liver). Intrahepatic bile ducts are tiny tubes that can only be seen with a microscope, whereas extrahepatic bile ducts are large enough to show up in imaging tests.

2. Risk Factors for PBC and PSC

A person’s sex plays a big role in who gets PBC and PSC. Females have 10 times the risk of PBC compared with males, according to Cleveland Clinic, whereas PSC affects twice as many males as females. PSC is also strongly associated with inflammatory bowel disease (IBD), mainly ulcerative colitis.

PBC usually begins later than PSC, at an average age of 55. PSC is typically diagnosed between ages 30 and 40. The rates of both PSC and PBC are slightly higher in some parts of the world, including Northern Europe. Overall, both conditions appear to be on the rise, but researchers aren’t sure if that’s because more people are getting the disease or if it’s due to better practice guidelines for diagnosis.

Symptoms of either condition can overlap and include:

• Abdominal pain
• Jaundice
• Pruritus (itching)
• Fatigue
• High cholesterol

Your doctor can run various imaging and blood tests and may need to do a liver biopsy to figure out exactly what’s going on.

Many people don’t suspect PBC or PSC from the symptoms they experience. Rather, they find out they have it after being tested for another health issue. Members of myPBCteam have shared how they went to the doctor for another issue before finding out about PBC.

“In the summer of 2023, I had Helicobacter. Once that was treated, I developed upper right quadrant pain,” said a member who’d had a Helicobacter pylori infection. “I kept thinking it was my gallbladder, so I went to my doctor. It was my gallbladder, but I got a ‘two-for-one’ deal. The ultrasound showed my liver is normal, and I’ve started medication, and my numbers are coming down.”

Several genetic and environmental factors have been considered possible triggers for both conditions, but scientists have yet to determine the underlying causes.

3. Comorbidities and Complications

People with PSC are more likely to develop certain comorbidities (co-occurring health problems) or complications. For example, up to 80 percent of those with PSC also have IBD, especially ulcerative colitis (75 percent of the time). PSC is also linked to a higher risk of bile duct cancer, gallbladder cancer, liver cancer, and colorectal cancer (for those with IBD). However, these cancers aren’t associated with PBC.

People living with PSC and IBD need regular colonoscopies to catch colorectal cancer early. According to the journal Pathologica, having IBD alone increases colon cancer risk by about 10 times compared with the general population. A diagnosis of PSC on top of IBD raises this risk even more — by about fourfold.

People with PBC are most likely to have a variety of other autoimmune diseases. Although PSC is linked to autoimmune diseases other than IBD about 25 percent of the time, about 55 percent of people with PBC also have another autoimmune disorder, such as thyroid disease or Sjögren’s disease. This higher rate isn’t that surprising when you consider that PBC is more common in females, who tend to get autoimmune disorders more often than males.

Some members of myPBCteam have discussed their history of autoimmune disorders. “I have had vague autoimmune symptoms for most of my life, including irritable bowels, dry mouth and eyes, skin rashes that come and go, loss of color along my knuckles, and fatigue,” one said. Other members have shared memories of dry skin and itching that started in childhood.

4. Treatment Options for PSC and PBC

Current treatments for PBC include medications like ursodiol — also known as ursodeoxycholic acid (UDCA). UDCA modifies bile in a way that helps protect the cells and slow the disease progression.

Most people with PBC respond well to UDCA, but about 40 percent don’t have a strong enough response. Healthcare providers may recommend additional medications like fenofibrate. Another treatment, elafibranor (Iqirvo), may be used in addition to UDCA or on its own. With end-stage PBC and severe liver damage, a liver transplant can be a successful and lasting way to treat the disease.

Sometimes, people with PSC can also benefit from a liver transplant, but not if they’re very sick.

Liver transplants are not recommended for PSC if bile duct cancer has spread beyond the liver. Fortunately, new treatments are being developed. Your doctor can help you manage the symptoms of PSC with medication to reduce itchiness, antibiotics for infections, and vitamins to treat nutrient deficiencies.

More Similarities Than Differences

Despite these differences, PBC and PSC share many characteristics. Not only do both conditions primarily affect the liver, but they’re also both rare diseases that can take time to diagnose and significantly affect quality of life. It’s easy to feel alone when facing a disease you’ve likely never heard of before.

On myPBCteam, members share honest feelings about their diagnosis. “At first, it was overwhelming and dooming,” one member said. “Getting diagnosed was a relief that validated my symptoms, but there was not much support from family and friends. They couldn’t see a physical ailment and expected me to go on as they wished, even when I didn’t sleep or feel well. They really hesitated to talk about it or learn info about it. As time passed, I transformed into accepting my health issues.”

Learning that others can relate to your experience can help bring comfort and hope as you keep pushing ahead.

Talk With Others Who Understand

On myPBCteam, people share their experiences with primary biliary cholangitis, get advice, and find support from others who understand.

Have you been diagnosed with PBC? Do you have advice for others living with the condition? Let others know in the comments below.