Dandruff which is like a scalp infection that comes with white scalp and itches too can be caused by different problems like dirty hair and scalp, oily scalp,dry skin too, a scalp that is very sensitive to hair products, fungus infection on the scalp and lot more. It is pertinent to find out the root cause that the solution could be started from the root. I think with a dirty hair washing the hair often with hair shampoo ,applying a Moisturizer and keeping the hair dryer can help prevent dandruff. You can meet with good hair dressers to treat dandruff, they're specialists and dandruff can be treated better by them. Don't forget to buy very good hair cream especially the ones with mints or mentols to help keep dandruff at Bay.