This Is When You Should Worry About Swollen Lymph Nodes

Even though sore, swollen lymph nodes in your head or neck are not really something anyone wants to experience, they are a sign of something really important — your body's effort to fight off infection.

Lymph nodes (they're not actually glands, even though they're often referred to in that way) are part of the body's lymphatic system, which is a network of blood vessels, lymph nodes, and organs that are spread throughout the body, grouped mostly in the neck and head, arms, abdomen, and groin (via Mayo Clinic). They are an important part of the body's immune system, acting like a filter that traps viruses, bacteria, and anything else that could cause an illness, and destroying the pathogens on site (via Verywell Health). Sterling Ransone, M.D., president of the American Academy of Family Physicians, told Health, "They're catching the bad guys—our immune system is chewing them up."

Most of the time, swollen lymph nodes are noticeable in the head or neck, and swell in response to upper respiratory infections caused by viruses or bacteria. The swelling is a result of extra blood cells accumulating at the site of infection to fight off the pathogen. Sinus infections, strep throat, and mononucleosis can also lead to swollen nodes.

Swollen lymph nodes will usually return to normal, often without treatment, when the underlying infection is resolved (per Cleveland Clinic).  Amy Zack, M.D., a family medicine physician at Cleveland Clinic, says "It is really time and the resolution of the viral illness or inciting cause of the swelling that will help the symptoms improve" (via Health).

But if they persist, or if they are growing rapidly, are more than an inch wide, are painful, or accompanied by other concerning symptoms like fever, it's important to check in with your doctor. In rare cases they can indicate a more serious condition, like cancer. Dr. Zack adds "When lymph nodes in the neck are enlarged for more than seven to 10 days or there are no symptoms of a cold virus or other infection such as strep throat, it is vital to talk with the doctor about why this is the case."