Swelling next to the ear, for children, could be mumps, which in this case is usually caused by a viral infection, and if this condition is considered, it needs to be treated with symptomatic treatment at the dentistry department as soon as possible. For adults, swelling next to the ear may have the following diseases. The first one is sebaceous cyst infection behind the ear, which is more likely to occur in patients who are obese, usually like to eat greasy, spicy, stimulating, and like to stay up late, for this condition, anti-inflammatory and other treatments are usually needed. If the cyst is large and an abscess is formed locally, an incision and drainage will be required. The second disease is adult mumps, which is mainly caused by bacterial infection, and clinically requires anti-inflammatory and symptomatic treatment. There are other diseases, such as inflammation of the lymph nodes behind the ear, and some patients have some throat or ear infection involving the lymph nodes around the ear, resulting in lymph node inflammation, which should also have this possibility.