What effect does malassezia have on the scalp?

Malassezia is a type of yeast that is naturally occurring on the skin and scalp. In certain conditions, it can lead to an overgrowth that disrupts the normal balance of the scalp's microbiome. This overgrowth is often associated with increased oiliness, which can contribute to scalp conditions such as dandruff and seborrheic dermatitis. One of the key symptoms of these conditions is dryness and itchiness, which result from an inflammatory response that occurs when the yeast proliferates beyond normal levels.

The correct answer reflects the commonly accepted understanding that an overgrowth of malassezia can lead to discomfort on the scalp, characterized by these symptoms. It does not actively nourish the scalp or protect against infection; in fact, an imbalance caused by malassezia can sometimes lead to other issues, including various skin infections. Therefore, the choice indicating that it creates dryness and itchiness is accurate in highlighting the negative impact that malassezia can have when it overgrows on the scalp.