Lymph nodes are located all over the body and are important immune organs of the body. The causes of swollen axillary lymph nodes need to be analyzed. Common causes of swollen axillary lymph nodes may include: first, infection. Swollen axillary lymph nodes with pain are considered to be caused by acute inflammation, which can often cause redness, swelling, heat and pain, and other manifestations of inflammation. The causative agent may be acute cellulitis purulent inflammation caused by bacteria and viruses, while infections like those in the upper limbs can also cause swelling of axillary lymph nodes. Second, tumor. If the lymph nodes in the armpit are painlessly enlarged, lymphoma or metastatic cancer can be considered. Localized lymph node enlargement with low-grade fever, night sweats and wasting cannot exclude the possibility of tuberculosis. Various acute and chronic leukemias, plasma cell tumors, multiple myeloma, and primary proteinemia can also cause swollen axillary lymph nodes. If axillary lymph nodes are found to be enlarged with periodic fever, this condition should be considered as a possibility of malignant lymphoma, or other metastatic tumors, such as common axillary metastatic tumors, which may be breast cancer, lung cancer, gastric cancer, rhinitis cancer, etc. Meanwhile, certain reactive hyperplasia can also cause axillary lymph node enlargement, such as systemic lupus erythematosus, nodular disease, and necrotizing hyperplastic lymphadenopathy, all of which can cause axillary lymph node enlargement. We should go to a regular hospital for examination to clarify the cause of axillary lymph node enlargement and treat it symptomatically to achieve better results.