While snooping around in the mouth of a patient, doctors in Singapore were confronted with a surprising symptom: a silky smooth tongue, seemingly without any taste buds.
As reported in The New England Journal of Medicine, the 64-year-old man came to the hospital saying he had been suffering from a painful tongue and burning sensations around his lips for six months. A physical examination revealed that the man had “an atrophic, erythematous tongue with loss of the lingual papillae,” which is science-speak for an inflamed red tongue and a loss of taste buds.
His blood tests came back relatively normal, except for extremely low levels of vitamin B12. A vitamin B12 deficiency can occur for a number of reasons. It can occasionally arise due to a lack of the vitamin in your diet, however, the most common cause is pernicious anemia, a condition where your immune system attacks healthy cells in your own stomach, preventing your body from absorbing vitamin B12 from the food you eat. The doctors made a diagnosis of pernicious anemia by detecting high levels of autoantibodies (a kind of antibody that targets the body's own proteins) in the man's blood, which suggested his immune system was pushing an attack on his own proteins.
Vitamin B12 is involved in the metabolism of every cell of the human body and in the development of red blood cells. If you have a deficiency of this vitamin, then your body struggles to make enough healthy red blood cells. Typically, a deficiency in vitamin B12 will lead to headaches, weakness, weight loss, and chest pain.
A sore and inflamed tongue is also a surprisingly common red flag for the condition. It’s unclear why tongues appear to be so affected by the deficiency, however, it has been previously noted that the oral mucosa, the mucous membrane lining the inside of the mouth, is especially sensitive to a lack of vitamin B12. It appears that the smooth appearance of the tongue is actually a result of inflammation, which has blown up the tongue like a balloon and created the impression that the bobbly taste buds have disappeared.
Fortunately, the man’s tongue is now back to normal, taste buds and all. However, due to his ailment, he has to receive monthly injections of vitamin B12 every month.