What are swollen lymph nodes?
Lymph nodes are part of your lymphatic system Overview of the Lymphatic System The lymphatic system is a network of lymphatic vessels and lymph nodes that carry fluid called lymph. The lymphatic system is part of your immune system, which helps defend against infection... read more , which helps fight infection and cancer. Lymph nodes are pea-sized collection points that filter out germs and cells from lymph fluid. Lymph nodes are located throughout your body, but many are clustered in your neck, under your arms, and in your groin. They swell when your body has an infection or cancer.
The cause of the swelling is usually a nearby skin or tissue infection or a harmless virus that goes away on its own
Sometimes the cause is a more serious infection or cancer
Swollen lymph nodes may hurt, or they may be painless
Sometimes your doctor may do tests for certain infections or cancers
If the swelling in your lymph nodes doesn't go away in 3 or 4 weeks, doctors may do a biopsy (taking out part of the tissue to look at under a microscope)
People call swollen lymph nodes "swollen glands," but lymph nodes aren't really glands.
What causes swollen lymph nodes?
There are many causes of swollen lymph nodes. The most common causes are:
An infection in tissues near the swollen lymph nodes
For example, a sore throat Sore Throat Sore throat is pain in the back of the throat. A sore throat can be very painful and is usually worsened by swallowing. Many people with a sore throat refuse to eat or drink. Sometimes pain... read more or cold Common Cold The common cold is a viral infection. It's one of the most common illnesses people get. Colds spread easily from person to person, especially within the first 2 days of symptoms Symptoms include... read more can make lymph nodes in your neck swell up. Or a sexually transmitted infection Overview of Sexually Transmitted Infections STIs are infections that are passed from person to person through sexual contact, including oral sex. STIs may be caused by different types of germs, including chlamydia, gonorrhea, HIV, and... read more (STI) can make lymph nodes in your groin swell up.
Bodywide infections such as mononucleosis Infectious Mononucleosis (Mono) Infectious mononucleosis, often called mono, is a viral infection that is most common in teens and young adults. Mono is spread by close contact, such as kissing, with infected people Symptoms... read more , HIV infection Human Immunodeficiency Virus (HIV) Infection and AIDS The human immunodeficiency virus (HIV) is a type of virus called a retrovirus. It causes AIDS (acquired immunodeficiency syndrome), which is life-threatening. HIV is called an immunodeficiency... read more , or tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a common, serious infection caused by bacteria called Mycobacterium tuberculosis. TB affects millions of people worldwide, particularly in low-resource countries... read more can make lymph nodes all over your body swell up.
More dangerous causes of swollen lymph nodes are:
An infected lymph node
Normally, your body's immune defenses kill any live germs that get into your lymph nodes. But sometimes a few germs survive and cause an infection. An infected lymph node hurts, and the skin over it turns red.
Cancer cells often break off from a cancer and travel through lymph vessels to nearby lymph nodes. For example, breast cancer often spreads to the lymph nodes in the armpit that's on the same side as the cancer. Sometimes your immune defenses kill the cancer cells. But sometimes the cancer cells grow in your lymph nodes. Cancer usually makes lymph nodes very hard and stuck together.
However, probably less than 1% of people with swollen lymph nodes have cancer.
When should I see a doctor?
Not every person with swollen lymph nodes needs to go to a doctor right away.
See your doctor right away if a lymph node is:
Draining pus (thick, white or yellow fluid)
Call your doctor if you have any of these other warning signs:
A lymph node that is very large (an inch or more across the middle)
A lymph node that feels hard, like a stone
Risk factors for HIV infection Human Immunodeficiency Virus (HIV) Infection and AIDS The human immunodeficiency virus (HIV) is a type of virus called a retrovirus. It causes AIDS (acquired immunodeficiency syndrome), which is life-threatening. HIV is called an immunodeficiency... read more (such as being stuck with a needle used by another person or doing high-risk sexual activities)
Risk factors for tuberculosis Tuberculosis (TB) Tuberculosis (TB) is a common, serious infection caused by bacteria called Mycobacterium tuberculosis. TB affects millions of people worldwide, particularly in low-resource countries... read more (such as living or working with a person who has tuberculosis or having recently moved from an area where tuberculosis is common)
Unexplained weight loss
The doctor will decide how quickly you need to be seen based on the warning signs and other symptoms.
If you have no warning signs and you feel well, you can wait a week to see if the node returns to normal before calling your doctor.
What will happen when I see the doctor?
Your doctor will ask questions about your symptoms and warning signs and will examine you. If you clearly have a harmless problem, doctors will wait and see whether the lymph node swelling goes away. Otherwise, doctors will do tests based on what they think is causing your swollen lymph nodes. Tests may include:
Imaging tests, such as x-ray Plain X-Rays A plain x-ray is an imaging test that takes a picture of the inside of your body. It uses a low dose of x-ray radiation. X-rays show body parts according to how dense (solid) they are. Doctors... read more or CT (computed tomography) scan Computed Tomography A CT scan uses a large machine shaped like a large donut to take x-rays from many angles. A computer then takes the x-rays and creates many detailed pictures of the inside of your body. Each... read more
Lymph node biopsy, if swelling lasts more than 3 or 4 weeks
How do doctors treat swollen lymph nodes?
Doctors treat the cause of your swollen lymph nodes.