Not glamorous, but common: how to manage dandruff at home and when to get help

Dandruff is the mildest form of a condition called seborrheic dermatitis. At its worst, this condition leads to patches of red skin covered in tiny, greasy scales. Composite: The Guardian/Getty Images

You spy a scatter of white flakes on your collar. Or you’ve got an itch that won’t quit, no matter how much you wash your hair. Dandruff isn’t glamorous, but it’s common: about half the world’s population has it.

An itchy, flaking scalp is rarely dangerous, but it can be annoying. Here’s what you need to know about what might be causing your flakes, what you can do about it, and when it’s time to get help.