The term "swollen glands" refers to enlargement of one or more lymph nodes.

In a child, a node is considered enlarged if it is more than 1 centimeter (0.4 inch) in diameter.

See also: Lymphadenitis and lymphangitis

Lymph nodes are glands that play an important part in your body's defense against infection. They produce lymph, which travels throughout your body in the lymph system, and filters impurities from the body.

Common areas where the lymph nodes can be felt (with the fingers) include:

• Groin
• Armpit
• Neck (there is a chain of lymph nodes on either side of the front of the neck, both sides of the neck, and down each side of the back of the neck)
• Under the jaw and chin
• Behind the ears
• On the back of the head

Lymph nodes can become swollen from infection, inflammatory conditions, an abscess, or cancer. Other causes of enlarged lymph nodes are rare. By far, the most common cause of swollen lymph nodes is infection.

When swelling appears suddenly and is painful, it is usually caused by injury or an infection. Enlargement that comes on gradually and painlessly may, in some cases, result from cancer or a tumor.

Infections that commonly cause swollen lymph nodes include mononucleosis, German measles (rubella), tuberculosis, mumps, ear infection, tonsillitis, an abscessed or impacted tooth, gingivitis (swelling of the gums), mouth sores, and sexually transmitted diseases.

Immune or autoimmune disorders that can cause swollen lymph nodes include rheumatoid arthritis and HIV. Cancers that can cause swollen glands include leukemia, Hodgkin's disease, or non-Hodgkin's lymphoma.

Which lymph nodes are swollen depends on the type of problem and the body parts involved. Identifying the location can help determine the possible cause.

Swollen lymph nodes may also be caused by some medications (such phenytoin for seizures) or certain vaccinations (such as typhoid immunization).

Soreness in lymph glands usually disappears in a couple of days without treatment, but the nodes may not return to normal size for several weeks after the infection has cleared. Generally, if glands are painful, it is because they swell rapidly in the early stages of fighting an infection.