What is one sign of an infection?

Redness and swelling are classic signs of infection, as they indicate inflammation in response to an invading pathogen. When the body detects an infection, it initiates an immune response that includes increased blood flow to the affected area, leading to redness. The immune cells that move to the site of infection also cause swelling by accumulating fluid and other substances that contribute to the body’s defense mechanisms.

This physical manifestation is often accompanied by other signs of infection, such as warmth and pain at the site. While fever, fatigue, and headache can also be associated with infections, they are systemic responses that do not specifically indicate the localized signs of infection like redness and swelling do. The combination of these localized symptoms provides clear evidence that the body is fighting against an infection in a particular area.