DEAR DR. ROACH: I read your recent column on primary sclerosing cholangitis. What is the difference between this condition and primary biliary cholangitis? Where can I find information on how to get on a waiting list for a liver transplant?

• C.V.

ANSWER: Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are similar in some ways. They are both chronic and progressive liver diseases, whose initial symptoms can be vague (such as fatigue or skin itching) and can be found incidentally on laboratory testing. They are both largely thought to be autoimmune diseases that are probably triggered by something in the environment, and both cause the progressive destruction of the bile ducts.

As many as 80% of people with PSC have inflammatory bowel disease (IBD), especially ulcerative colitis. Some people with PBC also have IBD, but symptoms of Sjogren’s syndrome (dry eyes and mouth) are more common. PBC is most common in women between 40-70, while PSC is more common in younger men. There is a lab test for PBC (anti-mitochondrial antibodies are found in more than 95% of cases), but PSC doesn’t have a specific lab test.

PBC is more amenable to treatment, with ursodeoxycholic acid (Actigall) slowing disease progression and improving survival. Actigall is sometimes tried in people with PSC, although there isn’t a proven survival benefit with PSC the way there is with PBC.

Liver transplant is the definitive therapy for both conditions. A person with PBC is considered for a liver transplant when they have cirrhosis and complications. (Physicians use a scale called the MELD score to quantify cirrhosis, and a score above 15 is the usual indication to list a person for a transplant. But there are other considerations.) Your liver specialist should be discussing with you whether a transplant is in your future.

Cancer (most commonly in the bile ducts and liver but also in the colon, gallbladder and pancreas) is a significant problem with PSC, and the likelihood of developing cancer is nearly 1% per year. The risk of cancer with PBC is increased compared to the general population, but it’s much smaller than in people with PSC. However, once a person has cirrhosis of any kind, liver cancer does become much more likely than it is with the general population.

Dr. Roach regrets he can’t answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.