Boy's bright-yellow tongue was a sign of rare disorder

A boy's yellow tongue (left) was a sign of a rare autoimmune disorder. He also developed dark urine (right). (Image credit: The New England Journal of Medicine ©2021)

For a 12-year-old boy, a yellow tongue was a sign of a serious and rare disorder, according to a new report of the case.

The boy went to the hospital after he experienced a sore throat, dark urine, abdominal pain and pale skin for several days, according to the report, published Saturday (July 24) in The New England Journal of Medicine.

Doctors at the Hospital for Sick Children in Toronto determined the boy had jaundice, a condition that usually causes a yellowing of the skin and the whites of the eyes, as well as dark urine. The boy indeed had a yellow tint to his eyes. But he also had a bright yellow tongue, which can be a symptom of jaundice in rare cases, according to The Mayo Clinic. (A number of ordinary things can also turn the tongue yellow, including dry mouth, certain medicines and poor oral hygiene, according to Healthline.)

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Jaundice happens when a yellow chemical called bilirubin builds up in the body, according to the National Institutes of Health (NIH). Bilirubin is formed during the normal breakdown of red blood cells.

But what was causing the boy's jaundice? After running a number of tests, doctors determined that a rare string of events led to his yellow tongue.

The boy had anemia, or a low red blood cell count. He also had an infection with Epstein–Barr virus, a common virus that usually infects people in childhood and causes mild or no symptoms. But Epstein–Barr virus infection has also been linked with a number of autoimmune conditions.

Blood tests revealed a specific antibody that can cause red blood cells to be broken down too soon.

He was diagnosed with cold agglutinin disease, a rare autoimmune disorder in which a person's immune system attacks and destroys its own red blood cells, according to the NIH. This autoimmune attack is triggered by exposure to cold temperatures between 32 and 50 degrees Fahrenheit (0 and 10 degrees Celsius), and so symptoms can be worse during winter months. The condition results in anemia and may also cause jaundice because the fast breakdown of red blood cells leads to a buildup of bilirubin. In some cases, cold agglutinin disease may be caused by certain infections, including infections with Epstein–Barr virus, according to the NIH. In this case, doctors suspect the Epstein–Barr infection triggered the boy's cold agglutinin disease.

The boy needed a blood transfusion and also received treatment with oral steroids for seven weeks to reduce immune system activity.

After the boy left the hospital, he "recovered well," and his tongue color gradually returned to normal as levels of bilirubin in his body fell, the authors said.

Originally published on Live Science.  

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.