The bumps on the back of the neck are considered to be folliculitis, sebaceous cysts, boils, lipomas, and so on. 1. Folliculitis: mainly due to pathogen infection, trauma, clothing friction stimulation, decreased immunity are triggering factors. The disease will cause localized red papules and pustules, and may be accompanied by pain, itching and other uncomfortable symptoms, and some patients may be manifested as bumps on the back of the neck. 2. Sebaceous cysts: Sebaceous cysts are formed when the sebaceous glands of hair follicles are blocked, prompting the accumulation of sebum. When sebaceous cysts are found in the neck area, they can manifest as bumps on the back of the neck. Usually, sebaceous cysts are single, moderately hard or elastic, but without fluctuating sensation, smooth surface and clear boundary. 3. Boil: It is mostly caused by pathogens such as Staphylococcus aureus and Streptococcus aureus, etc. Scratching the skin, high temperature environment and bad hygiene habits are the triggering factors. Boils may also cause bumps on the back of the neck in some patients, and may be accompanied by other uncomfortable symptoms such as increased skin temperature, pain and swelling. 4. Lipoma: the cause is still unclear, and may be related to genetic factors, chronic inflammation and so on. The typical symptom of patients is one or more lumps under the skin, which may be manifested as bumps on the back of the neck. When the size of the lipoma increases and causes pressure on the surrounding tissues, it is easy to be accompanied by pain and numbness. It is recommended that people with lumps on the back of the neck should seek medical examination in order to clarify the cause of the disease and then follow the doctor’s instructions for treatment.