Lymph nodes are part of the body’s immune system. A swollen lymph node in the armpit may be a sign of a bacterial or viral infection, an injury, or a serious health condition, such as cancer.

Medically reviewed by Daniel More, MD Allergies occur when your immune system overreacts to allergens like pet dander, pollen ...

Discover how allergies can cause swollen lymph nodes, and learn to distinguish between normal immune responses and warning ...

She has been working at PEOPLE since 2017. Although swollen lymph nodes can be a sign of cancer, doctors are cautioning people who have recently received the COVID-19 vaccine not to jump to any ...

Sometimes, a person may have an immune disorder that causes lymph nodes to swell. Less common causes of swollen lymph nodes include: metastatic cancer, which is cancer that has spread from its ...

Swollen lymph nodes in your neck, armpit, head, and other parts of the body often occur when your body is fighting an ...