What is the primary cause of dandruff?

The primary cause of dandruff is malassezia yeast overgrowth. This yeast is a type of fungus that naturally exists on the scalp of most people. However, some individuals may have an overgrowth of this yeast, which can lead to irritation and an increase in skin cell turnover. This accelerated turnover causes dead skin cells to accumulate, resulting in the visible flakes associated with dandruff.

Understanding this process sheds light on why treatments often focus on antifungal agents, which target the malassezia yeast to help restore balance to the scalp's microbiome. While allergic reactions, environmental factors, and excessive oil production can contribute to scalp issues, the overgrowth of malassezia is the most direct and common cause of dandruff.