The short answer
Swollen lymph nodes are usually a sign the immune system is fighting an infection, and they normally shrink within a few weeks. A node is more worth checking when it is painless, hard, larger than about a half-inch, keeps growing, or lasts more than a few weeks.
Swollen lymph nodes are usually caused by infections, not cancer.
They often appear with colds, sore throats, or skin infections and settle in a few weeks.
A node that is painless, hard, fixed, or growing is more worth checking.
Nodes that last more than a few weeks deserve a doctor's look.
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The full explanation.
The simple version
Lymph nodes are small glands that are part of your immune system. When they swell, it usually means they are doing their job fighting an infection nearby — a cold, sore throat, ear infection, or skin infection. This kind of swelling is common and settles as you recover.
What usually causes swollen nodes
Most swollen nodes come from viral or bacterial infections. You might notice tender lumps in the neck, under the jaw, in the armpits, or in the groin. They are often sore, which actually points more toward infection than cancer.
What makes a node more worth checking
A lymph node is more worth a doctor's look when it is painless and hard, does not move easily, is larger than about a half-inch, keeps growing, or has been swollen for more than a few weeks without an infection to explain it — especially with night sweats, weight loss, or fevers.
When to see a doctor
See a doctor about a lymph node that lasts more than a few weeks, keeps growing, or is hard and painless, particularly with other symptoms. Most swollen nodes turn out to be from infection and settle on their own.
Words to know
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Common questions
▸Does a swollen lymph node mean cancer?
Usually not. Most swollen nodes are caused by infections and shrink within a few weeks. Only a minority are related to cancer.
▸Which nodes are more concerning?
A node that is painless, hard, fixed in place, larger than about a half-inch, or lasts more than a few weeks is more worth checking.
▸Are painful nodes better or worse?
Tender, painful nodes usually point toward infection. A hard, painless node is more worth checking, though any lasting node deserves a look.
▸How long should a swollen node last?
Most settle within two to four weeks. A node that stays swollen longer is worth a doctor's review.
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