Swollen lymph nodes

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Swollen lymph nodes occur when the body is fighting an infection. Learn how to identify swollen lymph nodes and care for your child.

Key points

Most often, lymph nodes swell when they are fighting an infection.
Swelling due to viral upper respiratory infections, such as the common cold, will disappear on its own.
Swelling due to bacterial infections, such as strep throat, is treated with antibiotics.
Bring your child to their health-care provider if the lymph node is red, painful or getting larger or if it is not shrinking after a few weeks.

Introduction

What are lymph nodes?

Lymph nodes are an important part of the immune system. They act like tiny filters, catching viruses and bacteria for white blood cells to destroy. They also produce substances that help kill infection-causing germs.

The body has over 600 lymph nodes. These are located all around the body except for the brain and heart. Most lymph nodes are found in groups under the skin in the armpit, groin and neck. They are also found deep in the chest and abdomen.

Lymph nodes usually measure 0.5 to 1.5 cm across, depending on where they are located. In general, lymph nodes are about the size of a pea.

What are swollen lymph nodes?

Swollen lymph nodes (lymphadenopathy) occur when the body is fighting an infection. Young children are constantly being exposed to new infections, so their lymph nodes are often larger than those of adults.

Causes, risk factors and prevalence

Causes of swollen lymph nodes

Identification of the adenoid, tonsil, thymus gland, spleen and lymph vessels in a boy — The lymphatic system is an important part of the body's immune system. It is made up of a network of lymph nodes and vessels which make and move substances that fight infection by destroying germs in the body. Examples of lymph nodes include the tonsils and adenoids.

Lymph nodes can swell because they are reacting to an infection or if they are infected.

Reactive lymph nodes

Your child's lymph nodes will swell in a certain part of the body when they are fighting an infection nearby. If the lymph nodes are infected by a virus, such as a cold, or bacteria, as in strep throat, they can grow to about two centimetres in the neck area. This slight enlargement, along with mild tenderness, means the lymph nodes are reacting to the infection and working to control it.

Infected lymph nodes

If your child's lymph nodes are very tender, grow larger and the surrounding skin turns red, the lymph nodes may be infected themselves. This condition is known as lymphadenitis.

Lymphadenitis is treated with antibiotics. Children who have lymphadenitis with a high fever, a lot of pain and difficulty drinking or swallowing may need to be admitted to hospital for IV antibiotics (antibiotics given through the vein).

Other possible causes of swollen lymph nodes

Skin infections, rashes and insect bites may cause lymph nodes to get larger.
Rarely, lymph nodes can be swollen because of some types of cancer, such as leukemia or lymphoma.

Treatment

How to treat side effects of swollen lymph nodes

Swelling

Swollen lymph nodes caused by a viral infection will shrink to normal size on their own in about two to four weeks. If your child has a bacterial infection, their health-care provider will prescribe antibiotics to treat the underlying cause of the swelling.

In some cases, it can take up to one month or more for the swelling to disappear completely.

Pain or fever

For pain or fever, you can give your child acetaminophen or ibuprofen as directed on the bottle, by a pharmacist or your child's health-care provider.

When to seek medical attention

When to see a health-care provider for swollen lymph nodes

See your child's health-care provider if:

Your child has a fever or develops a sore throat.
The skin around the swollen node is red and painful.
The lymph nodes continue to grow or do not shrink to normal size over a few weeks.
Your child develops unusual bruising or is losing weight.

Go to the nearest emergency department if:

The node grows to four or more centimetres across.
Your child has difficulty breathing or moving their head.

Last updated: March 15th 2024