Swollen lymph nodes and fever may be related to lymphadenitis, leukemia, lymphoma and other causes. 1. Lymphadenitis: When the body is infected by bacteria, viruses and other microorganisms, the inflammatory factors produced can invade the lymph nodes through the lymphatic vessels, resulting in the enlargement of these lymph nodes and the formation of lymphadenitis, which is often accompanied by fever, pain and other symptoms. 2. Leukemia: Common symptoms include fever, enlarged lymph nodes, progressive anemia, significant bleeding tendency or bone and joint pain. 3. Lymphoma: Lymphoma patients most commonly have enlarged lymph nodes in the neck, armpits or groin, and may have fever and unexplained weight loss. It is recommended that people with enlarged lymph nodes and fever should go to the hospital in time to clarify the cause of the disease and carry out standardized treatment under the guidance of doctors to avoid delaying the condition.