What is the primary cause of dandruff?

The primary cause of dandruff is an overgrowth of yeast on the scalp. This yeast, specifically a fungus known as Malassezia, is part of the normal flora found on the scalp. However, for some individuals, this yeast can proliferate, leading to an increase in scalp cell turnover. As the old skin cells die and flake off, they combine with excess oil and become visible as white flakes, which is recognized as dandruff.

It's important to note that while other factors such as dry scalp, allergic reactions, or infrequent washing can contribute to scalp issues, they do not directly address the primary mechanism behind dandruff formation. Dry scalp can lead to flakiness, but it is not the root cause like excessive yeast growth. Allergic reactions might cause irritation or inflammation but are not the common trigger for dandruff. Similarly, infrequent washing could result in a buildup of skin cells and oil, yet it is the yeast overgrowth that fundamentally leads to the characteristic symptoms of dandruff.