What is a common sign of infection?

A common sign of infection is characterized by redness, warmth, swelling, and pus formation. When the body is fighting an infection, it initiates an inflammatory response. This response is evident through local symptoms: redness occurs due to increased blood flow to the area, warmth results from that increased blood flow and metabolic activity, and swelling arises from the accumulation of fluids and immune cells mobilized to the site of infection. Pus formation indicates the presence of dead white blood cells, bacteria, and tissue debris, which are typical in many infective processes.

The other options, while they may indicate other skin conditions, do not cover the full spectrum of symptoms typically associated with infection. Itching and redness often suggest irritation or an allergic reaction rather than a confirmed infection. Dry skin and irritation can result from environmental factors or skin disorders but do not inherently signal an infection. Pimples and rashes can be associated with various dermatological conditions, including acne or skin allergies, rather than a definitive infection. Thus, the detailed combination of symptoms listed highlights the typical clinical picture of an infection.