Why have i got dry scalp with flakes of dandruff after washing hair? x?

a lot of dandruff is caused by scalp build up. try using head and shoulders 2-3 times a week, it works for me. also when u wash your hair concentrate on rubbing the suds on your scalp, but dont scratch. AND, this may seem counter-intuitive, but rub some conditioner in your scalp as well... it makes it easier to rinse away the dead skin. good luck!