Swollen Lymph Nodes

Lymphatic System
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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?

The body has over 600 lymph nodes, or "glands”. Most lymph nodes are found in groups near the armpit, groin and neck. They are also found in the chest and abdominal cavities away from the surface of the skin. Most parts of the body have lymph nodes except for the brain and heart.

The size of normal lymph nodes can range between 0.5 to 1.5 cm, depending on where they are located. In general, lymph nodes are about the size of a pea.

Lymph nodes are an important part of the immune system. They help stop the spread of infection. 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.

Swollen lymph nodes (lymphadenopathy) are common in children. Because young children are constantly being exposed to new infections and antigens, their lymph nodes are often larger than those of adults.

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, significant pain and difficulty drinking or swallowing, may need to be admitted to hospital for IV antibiotics.

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 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.
  • Swollen lymph nodes on the front of the neck could mean your child has a cold or throat infection​.

How to treat symptoms 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 shrinking back to normal size. In some cases, it can take up to one month or more for the swelling to disappear completely.


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

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 many weeks
  • your child develops unusual bruising
  • your child is bleeding excessively from the nose or mouth
  • your child is losing weight.

Seek urgent medical attention 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, like the common cold, will disappear on its own.
  • Swelling due to bacterial infections, like strep throat, will disappear with antibiotics.
  • Give your child acetaminophen or ibuprofen to treat pain or fever.
  • Make an appointment with your child’s doctor if they develop unusual bruising or are losing weight.
Shawna Silver, MD, FRCPC, FAAP, P.Eng