What Is Geographical Tongue?

This is a medical term for a condition which can affect the tongue and make it have very zig zag white lines and red spots.  It is so called because the condition in fact makes the tongue resemble a map, hence the geographic reference.
It is quite a common condition, affecting about 2% of the population at any one time and does not usually cause ill health.  Some people with a geographic tongue find that the tongue may be a little more sensitive and it may cause some discomfort to eat very hot or spicy foods.  
No one really knows what causes it, although it does seem to run in families and is more common in people who suffer with psoriasis.  Usually it will clear up as quickly as it arrived, of its own accord, although it may re-appear in the future.  Whilst no medical treatment is required for this condition, it may just be worth checking with a doctor that it is in fact a geographic tongue and not a symptom of another illness.