If your head feels really itchy and you find small white or yellowish flakes falling onto your shoulders, the chances are that you have dandruff. Some people can also have dandruff in their eyebrows, but this is unusual. Wearing dark coloured clothes can be embarrassing, as the flakes show up particularly well on dark colours.
There is a lot of info about dandruff on the Better Health Channel
The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor or other health professional.