There are many reasons that cause patients’ underarm lumps, which may be caused by enlarged axillary lymph nodes, sebaceous cysts, lipomas, etc. Patients should seek medical treatment in time to make a clear diagnosis. 1. Enlarged axillary lymph nodes: may be due to infectious diseases caused by patients with swollen axillary lymph nodes, accompanied by redness, swelling, pain and other symptoms, at this time the patient can be under the guidance of the doctor to use cephradine, cephalosporin, cefixime, cefaclor and other drugs for treatment. 2. Sebaceous cysts: cysts may be formed due to the accumulation of sebum in the sebaceous glands, and patients may have bulbous cysts, which are mostly round, and sometimes can be seen as black plugs on the surface of the skin. At this time, patients can be surgically removed under the guidance of the doctor. 3. Lipoma: patients may have small, painless lumps in the armpits. At this time, patients can be minimally invasive surgery under the guidance of the doctor to remove. There may also be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.