There are various causes of swollen lymph nodes, and there are different types of swollen lymph nodes depending on whether they are limited or systemic. In the case of limited swollen lymph nodes, they can be caused by lymph node tuberculosis, lymph node metastases from malignant tumors, or lymphadenitis caused by inflammation of the lymph node drainage area, as well as acute inflammation of the lymph nodes themselves. Systemic lymph node enlargement can be seen in infectious diseases, such as infectious mononucleosis, AIDS, brucellosis, syphilis, leptospirosis, toxoplasmosis, or non-infectious diseases, such as systemic lupus erythematosus, hematologic lymphoma, malignant histiocytosis, leukemia, etc.