Swollen lymph nodes

Lymphatic System
Get Adobe Flash player
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 micro-organisms in the body. Examples of lymph nodes include the tonsils and adenoids.

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 near the armpit, groin and neck. They are also in the chest and abdominal cavities away from the surface of the skin.

Lymph nodes 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 and antigens, so their lymph nodes are often larger than those of adults.

You might sometimes hear or use the term “swollen glands” to describe swollen lymph nodes. However, the glands are not part of the immune system. Their role is to produce hormones that control different processes in the body.

Causes of swollen lymph nodes

Lymph nodes can swell because they are reacting to an infection or 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 a bacteria, as in a 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 well to control it.

Infected lymph nodes

If your child’s lymph nodes are very tender and grow to more than four centimetres and the surrounding skin turns red, the lymph nodes may be becoming 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

  • Cuts, burns, skin infections, rashes and insect bites may cause lymph nodes to get larger.
  • Swollen lymph nodes on the front of the neck could mean your child has a cold or throat infection.
  • Swollen lymph nodes in the groin could mean your child has an injury near their lower abdomen or legs.
  • Swollen lymph nodes in the armpit could mean your child has an injury near their arms or upper chest.
  • Swollen lymph nodes on the back of the neck could mean your child has an injury on their scalp.

How to treat side effects of swollen lymph nodes


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 doctor may prescribe antibiotics to treat the underlying cause of the swelling.

Avoid squeezing swollen lymph nodes. This may irritate them further and prevent them from returning to their normal size. 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 or by your child’s doctor.

When to see a doctor for swollen lymph nodes

Make an appointment with your child’s doctor if:

  • your child has a fever
  • your child develops a sore throat
  • the lymph nodes continue to grow or do not shrink to normal size over a few weeks
  • your child develops unusual bruising
  • your child is bleeding much more than they should from the nose or mouth
  • your child is losing weight.

Call 911 or go to the nearest emergency department if:

  • the skin around the swollen node is red and painful
  • the node grows to four or more centimetres across
  • a node in the neck is very swollen and your child has difficulty breathing or moving their head.

Key points

  • Lymph nodes swell when they are fighting an infection.
  • Treatment for swollen lymph nodes depends on the cause.
  • Swelling due to viral infections, such as the common cold, will disappear on its own.
  • Swelling due to bacterial infections, such as strep throat, will disappear with antibiotics.
  • Give your child acetaminophen or ibuprofen to treat pain or fever.
  • See your child’s doctor if your child develops unusual bruising or is losing weight or if their lymph nodes do not shrink after a few weeks.
Shawna Silver, MD, FRCPC, FAAP, PEng