Sudden growth of a bag next to the ear may be sebaceous cysts, lipomas, lymph node enlargement and so on. 1. Sebaceous cysts: most of the cysts are caused by the sebaceous gland duct obstruction, the gland content accumulation, which will lead to the patient’s sudden growth of a bag next to the ear, and after infection, it will be accompanied by redness, swelling, pain and other symptoms. 2. Lipoma: this disease is mainly related to genetic and fat metabolism abnormalities and other factors, after stimulation, tumor-causing factors will be in an active state, so that the normal fat cells undergo abnormal proliferation, resulting in the patient’s ear next to the sudden growth of a bag, usually smaller painless lumps. 3. Enlarged lymph nodes: a sudden growth of a bag next to the ear may be caused by enlarged lymph nodes, which mainly occurs after infection with bacteria, viruses and other causes of inflammatory reaction, and accompanied by pressure and pain and other symptoms. It is recommended that the patient go to the hospital in time to get a clear diagnosis and take targeted treatment.