Common causes of bumps on the side of the ear include boils on the side of the ear, folliculitis and sebaceous cysts. 1. Boils on the ear: When the ear is infected by pathogenic bacteria such as Staphylococcus aureus and forms a boil on the ear, the skin and neighboring tissues around the ear will grow boils, i.e., bumps on the ear, under the stimulation of the pathogenic bacteria. 2. Folliculitis: If pathogenic microorganisms such as bacteria, parasites or viruses infect the hair follicles on the skin around the ear and cause folliculitis, it can cause localized pore blockage, blood vessel dilation and tissue fluid exudation, which can be manifested as a pimple on the side of the ear. 3. Sebaceous cysts: The cysts are located in the skin and protrude towards the skin surface. The wall of the cyst is tightly adhered to the skin and there may be a small pigmented spot in the center. If you have a pimple on the side of your ear, you can actively go to the regular hospital to find out the cause of the disease, and under the guidance of a professional doctor to choose a suitable method of treatment.