Tennessee Cosmetology Practice Exam

A common cause of dandruff is indeed the presence of a dry scalp or an overgrowth of yeast. The scalp naturally harbors microorganisms, including a type of yeast called Malassezia. In some individuals, an overgrowth of this yeast can lead to irritation and an increase in skin cell turnover, resulting in the flakes associated with dandruff.

In addition to yeast overgrowth, dry scalp conditions can contribute significantly to dandruff. When the scalp lacks moisture, the skin can become dry and flaky, manifesting as dandruff. This dual mechanism—either the irritation caused by yeast or the dryness of the scalp—underlines why this choice is the correct answer in identifying the common causes of dandruff.

Other potential options like an oily scalp, excessive washing, and nutritional deficiencies can affect scalp health, but they do not consistently lead to the development of dandruff in the way that yeast overgrowth and dryness do. Excessive washing might aggravate or dry out the scalp, while oily scalp may lead to seborrheic dermatitis, which is more severe than typical dandruff. Nutritional deficiencies play a role in overall skin health, but they are not the primary or most common causes of dandruff.