Dandruff can cause either an overly dry scalp with itchy white flakes that may be waxy or greasy, or it can manifest as an oily scalp with
scales.
Dandruff is associated with a tiny fungus called Pityrosporum ovale, or P. ovale for short. This fungus lives on our bodies and scalp all the time, usually without causing a problem. Unfortunately, for some people, it can get out of control -- leading to dandruff.