Geographic tongue

What is a geographic tongue?
Geographic tongue is a common condition. It appears on the top and sides of the tongue, and sometimes on the under-surface. The tongue develops irregular, smooth, red areas, which may look like the outline of a map. There are usually wavy white lines next to the red patches.
You may notice that after a few weeks or months the position of these lines and red patches changes.
Why does it happen?
It happens because of the way the ‘old' surface of the tongue replaces itself. The top layer of the 'skin' of the tongue does not come away evenly. In some parts the 'skin' comes away too early and so leaves a red, sore area like a scratch on the skin. In other places the skin stays on too long and looks white.
The red areas, because they are thin, can sometimes become infected with thrush (candida) and so feel sore. Thrush is very common in mouths.
Who does it affect?
It affects all age groups and you may have first noticed it as a child. It is not s...