Swelling behind the ear is typically a result of an enlarged lymph node. People also refer to this condition as having swollen glands or swollen lymph nodes. Lymph nodes can be found in many places in the body, including the groin, armpits, neck, and behind the ears. The lymph nodes' primary function is to assist the body in eliminating foreign bacteria and infections. Swelling behind the ear can be caused by infections, injuries, or cancer.

The lymphatic system, which contains the lymph nodes, carries lymphatic fluids throughout the body. As this fluid passes through the lymph nodes, they filter bacteria and other infectious materials out of the system. On occasion, the lymph nodes themselves can become infected or enlarged due to other problems, which then manifest in swelling behind the ear. In the majority of cases, the swelling is due to an infection and normally lasts from a few days to a week. A doctor can usually identify the cause of a swollen lymph node by first identifying its location in the body.

When a person has a cold, the infection can trigger swelling behind the ear, on the neck, or on the jaw. Swelling in the armpit is a sign that a person has an infection affecting the arms or hands. If a person experiences swelling in the groin, an infection may be present in the legs or feet. In cases where the swollen lymph nodes are not caused by infection, the condition may be a result from an injury or from cancer. The three main types of cancer that produce swelling of the lymph nodes include leukemia, Hodgkin's disease, and non-Hodgkin's lymphoma.

Treatment for swelling behind the ear will depend on the exact cause of the condition. In cases where the swelling is due to an infection, antibiotics will usually be prescribed, and the swelling behind the ear should go away within a week. When the swelling is caused by an injury to the body, the injury itself will have to be treated, and the swelling behind the ear should then naturally go down on its own. If cancer is the cause for the swelling, a biopsy will have to be performed to diagnose the condition, and the doctor will then have to decide on the best route to take. Depending on the location and severity of the cancer, the lymph nodes themselves, along with other infected tissues, may need to be removed.