What is a common sign of infection in a patient?

Fever is a common sign of infection because it is a natural response of the body to fight off pathogens such as bacteria and viruses. When the immune system detects an infection, it releases pyrogens, which signal the hypothalamus in the brain to raise the body's temperature set point. This elevation in body temperature helps create an environment less favorable for the growth of pathogens and enhances the effectiveness of immune response.

While fatigue, nausea, and headache can also be associated with infections, they are more nonspecific symptoms and can occur in various other conditions. Fever is particularly indicative because it reflects an active immune response specifically targeting an infectious agent, making it a key clinical observation in the assessment of infection.