Lymph nodes are also called swollen lymph nodes, and there are many causes of swollen lymph nodes, as follows: 1. Swollen lymph nodes are caused by infectious factors, and many infections can lead to swollen local lymph nodes, such as swollen submandibular lymph nodes after upper respiratory tract infection, as well as swollen lymph nodes in front of and behind the ear, and swollen axillary lymph nodes due to skin inflammation in the chest, etc. 2. The causes of swollen lymph nodes may also be diseases of the lymphatic system, including lymphangitis or lymph node hyperplasia, etc. These diseases can be clearly diagnosed through blood tests, and once diagnosed, symptomatic treatment measures should be taken to deal with them. 3. In this case, the nature of the swollen lymph nodes can be determined by biopsy of the lymph nodes and finding the primary disease, and once the diagnosis is clear, symptomatic treatment should be taken in time.