(HealthDay News) -- If you notice swollen areas around your neck, behind your head or ears, or under your arms, you might be feeling swollen lymph nodes. Lymph nodes are a key line of defense against infection.
The U.S. National Library of Medicine offers this list of possible reasons for swollen lymph nodes:
- An ear infection.
- The gum disease gingivitis.
- A tooth that is impacted or abscessed.
- A sexually transmitted disease, including HIV.
- Sores in the mouth.
- Rheumatoid arthritis.
- Certain cancers, such as leukemia, Hodgkin's disease or non-Hodgkin lymphoma.