Possible causes of small bumps behind the child’s ear include enlarged lymph nodes behind the ear, sebaceous cysts, localized folliculitis or boils, and so on. 1. Enlarged lymph nodes behind the ear: It is more common to have enlarged lymph nodes behind the ear, which is mainly caused by inflammation and infection in the head and face, resulting in reactive lymphadenitis of the lymph nodes behind the ear, and the bumps will gradually subside after the primary disease subsides. 2. Sebaceous cysts: If the local pores are blocked, the oil secreted cannot be discharged in time, and sebaceous cysts may be formed over a long period of time. 3. Localized folliculitis or boils: If the surface of the bumps behind the ear is obviously red, swollen, painful, or even have small pus tips, it may be localized folliculitis or boils. There may be other reasons for the small bumps behind the ears of children, 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 under the guidance of the doctor.