Which of the following conditions may indicate a systemic infection?

Fever and chills are classic indicators of a systemic infection. When the body is responding to an infection that has spread throughout the system—such as sepsis or a severe viral infection—it often raises its temperature as a defense mechanism. Fever is a common physiological response intended to create an environment that is less hospitable for pathogens. Chills can accompany fever as the body attempts to reach and maintain a higher core temperature.

In contrast, localized pain, swelling, and fatigue can occur with both localized and systemic infections but do not specifically indicate that the infection has become systemic. Localized symptoms typically reflect an infection that is confined to one area of the body, such as a skin infection or an abscess. Fatigue can be both a symptom of localized infections or a general response to illness, but it does not in itself signify a systemic infection. Thus, the presence of fever and chills is more definitive in indicating that an infection may be affecting the entire body.