Causes of Dandruff:-

Dry skin – Dry skin is the most common cause of dandruff.

Dandruff can be developed if you are not shampooing your hair regularly.

Other skin conditions are also responsible for this problem like psoriasis (dry, rough and dead skin cells develops the thick scales) and eczema.

Risk factors

Almost anyone can have dandruff, but certain factors can make you more susceptible:

Age. Dandruff usually begins in young adulthood and continues through middle age. That doesn’t mean older adults don’t get dandruff. For some people, the problem can be lifelong.
Being male. Because more men have dandruff, some researchers think male hormones may play a role.
Certain illnesses. Parkinson’s disease and other diseases that affect the nervous system also seem to increase risk of dandruff. So does having HIV or a weakened immune system.