A lump at the top of the jaw line beneath the ear is indicative of a swollen lymph node, according to Healthline. Lymph nodes can be felt throughout the body and swell as a defensive response to illnesses and infections.
Causes of swollen lymph nodes in the neck area include ear infections, tooth infections, tonsillitis and viral infections, according to MedlinePlus. Cancerous conditions that can cause swollen lymph nodes include leukemia, Hodgkin's disease and non-Hodgkin's lymphoma. In many cases, swollen lymph nodes resolve on their own without treatment.
If the lymph nodes at the top of the jaw line have swelled in response to a respiratory infection, individuals may experience additional symptoms such as fever, runny nose and sore throat, according to Mayo Clinic. Immune system disorders such as rheumatoid arthritis may cause swollen lymph nodes throughout the entire body. Hard lymph nodes that continue to grow can signify cancerous tumors.
It is important for individuals with swollen lymph nodes to seek medical attention if symptoms are accompanied by severe sore throat, breathing difficulties or night sweats. Lymph nodes that have been present for two weeks or longer or swollen nodes that appear to have no underlying cause should also be examined by a physician, according to Mayo Clinic.