Which of the following is a clinical feature of vitamin B12 deficiency?

• A. Glossitis (swollen tongue)
• B. Palmar creases
• C. Jaundice only
• D. Hyperactivity

Answer: (A)

Vitamin B12 deficiency often shows changes in the mouth, with glossitis being a classic sign. Glossitis means the tongue becomes swollen, smooth, red, and sometimes painful because the mucosa isn’t renewing normally when B12 is lacking. This happens because B12 is essential for DNA synthesis in rapidly dividing cells, including the lining of the mouth, so its shortage leads to atrophic, inflamed mucosa.

For context, B12 deficiency can come from pernicious anemia, malabsorption, or very low B12 intake, and it can also cause fatigue, pale skin, and, importantly, nerve symptoms from demyelination. Among the other options, palmar creases don’t specifically reflect B12 deficiency. Jaundice can occur in megaloblastic anemia due to increased destruction of abnormal red cells, but it isn’t the defining feature and isn’t always present. Hyperactivity isn’t typical of B12 deficiency; mood and neurologic changes are more common, often including irritability or neuropathy rather than increased activity.