Which characteristic would suggest an infection in the lymph nodes?

Enlargement and tenderness of lymph nodes are hallmark signs that suggest an infection. When lymph nodes become infected, they typically respond by increasing in size due to the proliferation of immune cells as they actively respond to the invading pathogens. This enlargement often comes with tenderness because the inflammation and increased blood flow in the area make the nodes sensitive to touch. This response is part of the body's immune response, indicating that the lymphatic system is working to filter and combat the infection.

In contrast, features such as shrinking and firmness, visibility and pulsation, or asymmetry and immobility may not indicate an infection. Shrinking and firmness might suggest a different pathological process or a non-functional state. Visibility and pulsation are generally not standard signs for lymph nodes and often do not occur in cases of infection. Asymmetry and immobility can indicate other underlying issues but do not specifically point to an infection in the lymph nodes. Thus, enlargement and tenderness provide the clearest indicators of infection in this context.