What is a key symptom of HIV related to lymph nodes?

A key symptom of HIV related to lymph nodes is the swelling of lymph nodes, also known as lymphadenopathy. This occurs because the immune system is responding to the presence of the virus. As HIV attacks the body's immune cells, the lymph nodes — which are vital for immune function and are often sites where immune responses are initiated — can become enlarged as they work to fight the infection. This swelling may occur in various regions of the body, commonly in the neck, armpits, and groin. Recognizing this symptom can be crucial as it may signal a possible HIV infection, especially when accompanied by other signs such as fever or fatigue.

The other choices, while they may relate to various health issues, do not specifically pertain to the characteristic symptoms associated with HIV. Reddish sores, rashes, and diarrhea can occur in a range of other diseases and are not uniquely indicative of HIV.