Which of the following is a sign of a scalp infection?

Redness, swelling, and flaking of the scalp typically indicate a scalp infection because these signs suggest an inflammatory response from the body. When an infection occurs, the body's immune system reacts by increasing blood flow to the affected area, which can cause redness and swelling. Flaking can result from the skin reacting to infection, leading to irritation and an increased turnover of skin cells. Together, these symptoms form a classic presentation of inflammatory conditions, often associated with infections caused by bacteria, fungi, or other pathogens.

In contrast, dryness could point to conditions like psoriasis or dermatitis but isn’t primarily indicative of an infection. Oiliness often relates to overactive sebaceous glands and doesn't usually suggest infection. A color change could imply several different skin issues, not specifically pointing to an infection without additional context. Thus, the combination of redness, swelling, and flaking is the most clinically relevant for identifying a scalp infection.