What are swollen lymph nodes?

Lymph nodes, also known as lymph glands, are part of the lymphatic system, which fights infection. They act like filters for a type of body fluid called lymph. When the lymph passes through the lymph nodes, they remove waste and harmful germs.

If lymph nodes are swollen it means that these glands have become bigger. Swollen lymph nodes are also known as 'lymphadenopathy'.

What symptoms are related to swollen lymph nodes?

Glands in many different parts of the body can become swollen, but you're more likely to feel them in your neck, armpits or groin. You may have swollen glands in only one area of your body or in many different parts of your body at the same time.

If you have a swollen lymph node you may feel a lump under your skin.

You may have other symptoms, depending on what has caused the swollen lymph node. For example, with some infections you may have a fever or feel unwell.

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What causes swollen lymph nodes?

There are many different causes of swollen lymph nodes. Most of them are not serious.

Having swollen lymph nodes usually means that your immune system is fighting an infection in the area. For example, if you have a sore throat from a virus, you may get swollen neck glands. An infection in your leg can cause swollen glands in the groin.

Causes of swollen lymph nodes include:

• viruses (such as glandular fever)
• bacterial infections (such as tonsillitis)
• some autoimmune conditions
• some medicines
• eczema
• cancer

Out of 100 people with swollen lymph nodes, only one, if any, is likely to have cancer. In young people, cancer is even less likely.

Swollen lymph nodes are also a common side effect of some COVID-19 vaccines. This usually occurs on one side only, in the armpit of the arm that was injected. It is not dangerous and usually goes away on its own within a few weeks.

How is the cause of swollen lymph nodes diagnosed?

If you see your doctor about your swollen lymph nodes, they will ask you questions about your symptoms and examine you. They may be able to tell what the cause could be from the way the lump feels.

If you have a simple viral infection, you may not need any medical tests.

In some situations, your doctor might order blood tests or a scan, such as an ultrasound. If your doctor is concerned that your swollen gland may be caused by a cancer, you may need to have a biopsy of the lymph node.

When should I see my doctor?

You should see your doctor urgently if you have swollen lymph nodes plus any of these symptoms:

• fever
• night sweats
• unexplained weight loss
• bruising or bleeding easily

You should also see your doctor if your lymph nodes have stayed enlarged for longer than 2 weeks or have grown, or if you have a history of cancer.

You should also take your child to see a doctor if they:

• have difficulty swallowing liquids or breathing
• seem to be very sick

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How are swollen lymph nodes treated?

Treatment for swollen lymph nodes will depend on the cause.

Swollen lymph nodes caused by a virus don't need treatment. The glands will shrink back to their normal size. This may take a few weeks or longer.

If you have a bacterial infection, your doctor might give you antibiotics.

If your swollen lymph node is due to cancer, your doctor will refer you to a cancer specialist for treatment.

Sometimes, it may not be clear why your lymph nodes are swollen. If there are no worrying symptoms that suggest a serious illness, your doctor may recommend waiting a few weeks to see if your glands return to normal by themselves.

What are the complications of swollen lymph nodes?

A swollen lymph node caused by a bacterial infection could become an abscess (a pocket of pus). This may need to be surgically drained.

Can swollen lymph nodes be prevented?

Swollen lymph nodes can't be prevented. However, some of the viruses and bacterial infections that can cause swollen lymph nodes can be partially prevented by practising good hygiene.

Resources and support

SA Health provide more information about cervical lymphadenitis (enlarged lymph nodes due to an infection).

Cancer Australia explains the role of lymph nodes in breast cancer.

Call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.