Name a common skin condition that affects the scalp.

Dandruff is a prevalent skin condition that directly affects the scalp, characterized by flaking and sometimes itching. It occurs when the scalp is irritated or when there is an overproduction of skin cells that then die and flake off. The condition can be due to several factors, including dry skin, sensitivity to hair care products, or a yeast-like fungus known as Malassezia, which thrives on the scalp.

While eczema, alopecia, and psoriasis can also impact the scalp, they manifest differently. Eczema and psoriasis are inflammatory skin diseases that can lead to scaling and redness, but they often extend beyond the scalp or have more specific symptoms not limited to simple flaking. Alopecia refers to hair loss and does not directly indicate a skin condition affecting the scalp in the same manner as dandruff. Understanding these distinctions helps in identifying dandruff as the most common scalp-specific condition among the options presented.