There is a hard bag growing on the bone behind the ear which is painless and itchy. It may be a normal mastoid point and does not need treatment; it may also be caused by lymphadenitis, sebaceous cysts, etc., and can be treated with medication and surgery. 1. Mastoid point: It is a papillary bony protrusion at the outermost end of the lowest part of the skull in the area behind the ear, which looks like a hard bag to the touch. It is normal tissue and does not require treatment. 2. Inflammatory enlargement of lymph nodes behind the ear: inflammation around the ear can lead to enlargement of lymph nodes behind the ear, causing a hard bag on the bone behind the ear, the swelling can be painless and itchy, commonly used roxithromycin, ciprofloxacin and other drugs to fight infections and treatment, inappropriate use of the drug may be nausea, vomiting and other adverse reactions, allergic to the selected drugs are prohibited. 2. Sebaceous cysts: patients with sebaceous gland secretion behind the ear is more exuberant as well as hair follicle mouth blockage and other reasons can cause patients to form sebaceous cysts, resulting in patients with hard lumps behind the ear does not itch, patients can go to the hospital for resection of sebaceous cysts surgery, after the operation should pay attention to the prevention of infection and trauma cleaning. It is also possible to have a hard lump behind the ear which is painless and itchy due to lipoma, metastatic cancer, etc. It is recommended that the patient go to the hospital for examination to clarify the cause of the disease, and then standardize the use of medication and treatment under the guidance of the doctor.