xposure to the chemical bismuth, which is an ingredient in some medications, may cause the color change. Though it's often the entire tongue that turns black, the change could initially occur in patches.

Tongue pigmentation, or Pigmented Fungiform Papillae of the Tongue (PPT), causes black spots to appear on the tongue. These spots can be small specks or visible dark patches. While anybody can develop tongue pigmentation, individuals with dark skin tones are more likely to experience this condition than light-skinned people. They also tend to appear during childhood but can develop in adults as well.

Papillae look like tiny bumps on the surface of the tongue. There are four types of papillae:

• Filiform: Look like threads near the top and mid tongue
• Fungiform: Are mushroom-shaped spots toward the front of the tongue
• Foliate: Develop on the outer corners of the tongue
• Circumvallate: Appear on the top of the tongue toward the back of the mouth