Possible causes of swollen lymph nodes behind the ears include an ear infection, an abscessed tooth, a cold, the flu or another infection, according to MedlinePlus. Lymph nodes also commonly appear beneath the jaw, on the back of the head, or on the neck, armpit or groin.
Other infections that can lead to swollen lymph nodes include skin infections, tonsillitis, mouth sores, mononucleosis or gingivitis, states MedlinePlus. Swollen lymph nodes are also a symptom of tuberculosis and sexually transmitted diseases. In some cases, rheumatoid arthritis and cancers, such as leukemia and Hodgkin disease, cause the growth of lymph nodes. Seizure medications and typhoid immunization are also potential causes of swollen lymph nodes.
Lymph nodes usually feel painful as the body combats an infection, notes MedlinePlus. Most people experience pain relief after a few days without medical treatment. Swollen lymph nodes often diminish in size after several weeks.
The sudden occurrence of swollen lymph nodes typically indicates an infection or injury, whereas slowly developing swelling without pain may signal a tumor or cancer, explains MedlinePlus. It is important to contact a physician if the lymph nodes get bigger or remain swollen after several weeks. Red and tender lymph nodes that feel fixed, irregular or firm also require medical diagnosis. Individuals who experience unexpected weight loss, night sweats or fever should also consult a health care professional.