Is a Swollen Lymph Node a Sign of Cancer?

Usually not. Lymph nodes swell up all the time, almost always from infection. Lymph nodes are small, bean-shaped glands found in your neck, underarms, groin, and elsewhere. They are part of your immune system. When you fight off a cold or a cut gets infected, nearby nodes can swell as they do their job. Cancer, including lymphoma, is a less common cause. But a node that lasts, keeps growing, or comes with other symptoms is worth checking.

A node that swells up alongside a sore throat, a cold, or an infected cut is very likely reacting to that problem. These nodes are often tender to the touch. They tend to shrink back to normal within a couple of weeks, once the infection clears. This is the most common pattern by far, especially in children and younger adults.

The National Cancer Institute lists painless, swollen lymph nodes in the neck, underarm, or groin as a symptom of Hodgkin lymphoma, a cancer of the lymph system. A node that is painless is actually a clue worth paying attention to, since infected nodes are usually sore. Other features that raise concern are a node that keeps growing over several weeks, one that does not shrink after a reasonable time, or one that shows up with no obvious infection nearby. Lymphoma can also come with fever, drenching night sweats, and weight loss you did not try to lose — a group of symptoms doctors call "B symptoms."

Some medicines cause lymph nodes to swell as a side effect. Autoimmune conditions, where the immune system is overactive, can cause widespread swollen nodes. Dental infections often swell the nodes under the jaw. Cat scratches can cause a specific, well-known infection with lymph node swelling. Most of these causes settle on their own or with simple treatment.

Your doctor examines the node's size, texture, and location, and checks whether it moves freely under your skin or feels fixed in place. They ask how long it has been there and whether you have had a recent infection nearby. Blood tests, including a complete blood count, are common first steps. If the node stays enlarged for more than a few weeks with no clear cause, or other features raise concern, your doctor may order imaging, such as an ultrasound, or recommend a biopsy. A biopsy removes part or all of the node to look at under a microscope. Results usually take about a week.

If an infection seems like the likely cause, your doctor may reasonably choose to watch the node for two to four weeks rather than jumping straight to a biopsy. This is a normal, safe approach, not a delay in care. If the node has not gone down by your follow-up, or it has grown, that is when further testing usually follows.

• Call 911 or go to an emergency department if a swollen node in the neck comes with trouble breathing, noisy breathing, or trouble swallowing your own saliva. Do the same if your face or neck puffs up with breathlessness, or if the skin over a node turns red and spreading while you feel feverish and confused.
• Call your care team the same day if a node swells quickly over just a few days, or a swollen node arrives with drenching night sweats, weight loss you did not try for, or a fever that keeps returning.
• Call your care team within a day or two if a node has stayed swollen for more than a few weeks, keeps slowly growing, or feels hard and fixed rather than moving under your fingers.

• Could this swollen node be from an infection, or does it need further testing?
• How long should we watch it before ordering a biopsy?
• Should my other lymph nodes be checked too?
• What symptoms should bring me back sooner?

• National Cancer Institute — Adult Hodgkin Lymphoma Treatment (PDQ)
• American Cancer Society — Signs and Symptoms of Cancer