The scalp, like the rest of the skin, sheds dead skin cells. Dandruff occurs when this process speeds up. Dandruff flakes are actually dead skin cells.

The faster the scalp sheds dead skin, the worse dandruff becomes. Some factors can alter the rate at which the skin sheds.

According to the American Academy of Dermatology, researchers do not fully understand what causes dandruff. Potential causes of dandruff include:

• fungal infections of the scalp
• oils secreted by the scalp
• sensitivity to substances, such as hair products

These three factors may work together to make some dandruff worse. For example, people with fungal scalp infections may develop worse dandruff if they have sensitive skin or a very oily scalp.