The bulge in the armpit is considered to be caused by enlarged lymph nodes, paratesticular breasts, cysts and other causes, which need to be treated according to the causes, such as drugs or surgery. 1. Enlarged lymph nodes: If inflammatory stimulation causes enlarged lymph nodes, you need to use antibiotics under the guidance of a doctor, such as cefixime tablets, levofloxacin capsules and other antibiotics; if tuberculous lymphadenitis, you need to combine the application of isoniazid, rifampicin and other medications; if it is a metastasis of malignant tumors resulting in enlarged lymph nodes, you need anti-tumor therapy. 2. Paramastia: mainly refers to the appearance of breast-like tissue structure under the armpit, surgical methods can be considered for treatment, such as paramastectomy. 3. Cyst: Inside is liquid material, outside has complete envelope, if the volume is relatively large, it will also cause bulging in the armpit, need to be treated surgically, such as simple cystectomy. If the above symptoms occur, patients should pay attention, do not delay the condition, and seek timely treatment.