You’ve probably had swollen glands at some point in your life, such as when you’ve had a cold or other infection. Swollen glands are actually swollen lymph nodes, which are often reactive lymph nodes. You might also hear this condition referred to as reactive lymphadenopathy.

You have groups of small, bean-shaped lymph nodes all throughout your body. They’re located in your neck, underarms, chest, abdomen, and groin. They’re part of the lymphatic system, which is also part of your immune system. The lymphatic system helps fight off infections and keep them from spreading.

Your doctor may use the term “reactive lymph nodes” when examining you for a swelling or mass. If you have a biopsy of a mass, you might also see a reference to reactive lymph nodes when you review your lab results. This means your lymph nodes are reacting to something going on in your body.

However, it’s usually not a reaction to anything serious. In fact, most of the time, reactive lymph nodes are harmless. Reactive lymph nodes aren’t caused by an infection or cancer within the lymph node itself.

Read on to learn more about reactive lymph nodes, what causes them, and when you should be concerned.

Usually, you can’t feel your own lymph nodes. When they’re swollen or reactive, however, you’ll likely be able to feel them when your press your hands against your skin. They might feel as small as a pea or as large as a golf ball. You could even be able to see the swelling in your neck, armpits, or groin.

Keep in mind that you can have reactive lymph nodes in multiple areas of your body.

In addition to swelling, it’s possible to feel the following when you touch your lymph nodes:

  • tenderness
  • pain
  • warmth

Depending on the underlying cause, you might also have a range of other symptoms. If your lymph nodes are responding to an upper reparatory infection, for example, you could have a runny nose, sore throat, or fever.

Swollen lymph nodes can occur in just one area of the body or in multiple locations.

Reactive lymph nodes are a sign that your lymphatic system is working hard to protect you. Lymph fluid builds up in lymph nodes in an effort to trap bacteria, viruses, or other harmful pathogens. This helps to keep the infection from spreading to other parts of your body.

They also sometimes occur as a result of an autoimmune disease, such as lupus. These are conditions that involve your immune system mistakenly attacking our body’s tissues.

In addition, children often experience reactive lymph nodes as they first come into contact with new germs throughout childhood, even if they don’t have an infection.

Some common bacterial or viral infections that can cause reactive lymph node include:

Other causes include:

The location of the reactive lymph nodes can help you narrow down the cause. For instance, swollen lymph nodes in your neck may be due to an upper respiratory infection. A tooth infection might cause swollen lymph nodes around your jaw. HIV, mononucleosis, and immune system disorders can lead to swollen lymph nodes throughout your body.

Swollen lymph nodes are rarely caused by cancer. When they are, it’s usually related to lymphoma or leukemia, which both involve the lymphatic system. However, enlarged lymph nodes can also be a sign that other types of cancer, such as breast cancer, have spread (metastasized) to your lymph nodes.

Make an appointment with your doctor if you notice that your lymph nodes feel hard or immovable.

Reactive lymph nodes are usually a symptom of an underlying infection, so your doctor will start by asking about your other symptoms and taking your vital signs. They may also feel your lymph nodes and ask if you experience any pain or tenderness while they do it.

Depending on your symptoms and what they find during a physical examination, they may also order a blood test or imaging test, such as an MRI scan. They may also decide to biopsy a lymph node. This involves using a needle to take a small tissue sample and analyzing it for signs of cancer. If you have cancer, this can also help your doctor determine whether it’s spread.

Swollen lymph nodes often don’t need treatment. Some minor viral infections, such as the flu, simply have to run their course. Viral infections can’t be treated with antibiotics.

To help with painful or tender lymph nodes while you heal, try:

Other infections, such as bacterial infections, may require antibiotics or other medications. If you have an autoimmune condition or cancer, your treatment options will depend on the type and stage of your condition.

Reactive lymph nodes are usually just a sign that your immune system is doing its job by fighting off an infection. They should go down in size as you heal. If they feel hard or don’t seem to be shrinking back to their usual size as your illness resolves (usually within a week or two), contact your doctor.