Swollen Lymph Nodes: Why They Happen and When to Get Medical Care

You may be concerned if you have swollen lymph nodes. But before you worry, bear in mind that this swelling can be a normal response. Indeed, it's often a sign that your immune system is working hard to fend off an illness. However, in some cases swollen lymph nodes could be a sign of a serious medical condition that needs treatment.

Let's take a closer look at what causes swollen lymph nodes, when to see a healthcare professional, and how they're treated.

What are lymph nodes?

Lymph nodes are small, pea-sized glands that help the body recognize and fight infection. Your lymph nodes hold white blood cells (WBCs) that help rid your body of harmful germs that cause illness. Lymph nodes can be found in clusters throughout the body and are an important part of your immune system.

A normal lymph node is 1 cm in size or less and is not normally seen or felt in adults. But in children, it may be more easily detected.

Your body houses several hundred lymph nodes. Some lie just below the surface of your skin, while others reside deeper within your body.

How do lymph nodes work?

Lymph nodes play a key role as filters in your lymphatic system. Your lymphatic system is made up of a broad network of vessels, tissues, and organs that are important to your immune system. This network allows lymph (a clear fluid filled with blood cells, fats, and proteins) to flow throughout the body.

As lymph runs its course in the body, it collects and traps harmful matter, such as:

• Bacteria

• Body waste products

• Parasites

• Viruses

Lymph nodes work by filtering the lymph flowing through the lymphatic system. When your immune system recognizes germs or other foreign material, the WBCs in your lymph nodes get to work. The WBCs attack and remove any foreign substances that are detected. After this process, the filtered lymph fluid is released back into your bloodstream.

Swelling may occur as these germs, lymph, and WBCs build up within your lymph nodes. A lymph node that's greater than 1 cm in size can be considered swollen or enlarged. The medical term for a swollen lymph node is lymphadenopathy.

What causes swollen lymph nodes?

Swollen lymph nodes (lymphadenopathy) can be caused by many things, ranging from mild infections to serious illnesses like autoimmune diseases and cancer. The location of the swollen lymph nodes, and any other symptoms, can help to determine the cause.

In many cases, the swelling takes place at or near the area of the body that's affected. For instance, the lymph nodes in your neck may feel swollen when you have a sore throat, or an upper respiratory tract infection.

Sometimes, people have swollen lymph nodes in several areas of the body. This is called generalized lymphadenopathy and is sometimes seen in more serious illnesses.

Infections

Infections are the most common cause of swollen lymph nodes. Mild infections generally cause swollen lymph nodes in the area of the infection. Examples of these infections include:

• The common cold

• The flu

• Herpes

• Shingles

• Sinus infection

• Strep throat

More serious infections can cause generalized lymph node swelling along with other symptoms. Examples of these infections include:

• Chickenpox

• HIV

• Lyme disease

• Measles

• Mononucleosis

• Sexually transmitted infections (STI), such as syphilis

• Toxoplasmosis

Cancer

Cancer is a less common cause of swollen lymph nodes. Examples of cancers that cause lymph node swelling include:

• Breast cancer

• Kaposi's sarcoma (cancer of the blood vessels or lymph vessels)

• Leukemia (cancer of the blood cells)

• Prostate cancer

There are also cancers of the lymph nodes. These are called lymphomas. There are different types of lymphomas including:

• Hodgkin's lymphoma

• Non-Hodgkin's lymphoma

Lymphomas can cause swollen lymph nodes in the neck, armpit, collarbone area, and groin.

Autoimmune disease

Autoimmune diseases can cause swollen lymph nodes, too. Usually, the lymph node swelling in autoimmune diseases is in multiple areas of the body.

Examples of autoimmune diseases that can cause swollen lymph nodes are:

• Lupus

• Rheumatoid arthritis

• Sjögren's syndrome

Medications

In rare cases, vaccines, certain medications, or an allergic reaction to a medication can trigger lymph node swelling. Common vaccines and medications known to cause swelling include:

• Allopurinol

• Atenolol

• Captopril

• Carbamazepine

• COVID-19 vaccine

• Hydralazine

• Penicillin

• Phenytoin

• Primidone

• Pyrimethamine

• Quinidine

• Trimethoprim/sulfamethoxazole

Notify a healthcare professional if you have recently started a new medication and are concerned that your lymph nodes are swollen.

How to tell if your lymph nodes are swollen

You can't see or feel normal-sized lymph nodes. So, if you notice them, it's likely that they are bigger than they should be.

You're more likely to notice enlarged lymph nodes in places where the lymph nodes are near skin. Enlarged lymph nodes deeper in your body are not so easily felt.

What do swollen lymph nodes feel like?

Swollen lymph nodes can be painless. If they are inflamed or infected (something called lymphadenitis) they may be painful to the touch. And the surrounding skin may feel warm.

What do swollen lymph nodes look like?

Enlarged lymph nodes may be difficult to see if you don't know what you're looking for. If they're very large, then you may notice a lump. If there are several swollen nodes, you may see a cluster. If they're not as large but still swollen, you might just notice a fullness where there didn't used to be one.

Depending on the cause, you may also see skin changes around the lump. There might be redness, or there could be an opening in the skin, like a wound. Or even pus.

Where to look for swollen lymph nodes

Most people notice enlarged lymph nodes in:

• Their armpits

• The underside of their jaw

• Above their collarbone

• Their groin area

Other symptoms of swollen lymph nodes

When the cause of swollen lymph nodes is unclear, other symptoms may help point to the source. For instance:

• Joint pain, muscle weakness, or rash may indicate an autoimmune disease.

• Fever, chills, fatigue, and feeling unwell in general may suggest an infection.

• Fever, night sweats, and unexplained weight loss could indicate a serious infection, or cancer.

Treatments for swollen lymph nodes

When lymph nodes get swollen, it's usually in response to something else happening in your body. So the best way to treat swollen lymph nodes is to focus on whatever is causing them to swell in the first place.

If lymph nodes in your neck are swollen because you have strep throat, for example, treating the strep throat with antibiotics will help treat those lymph nodes.

If your swollen lymph nodes are causing you lots of pain, you can use at-home treatments like:

• Rest

• Warm compresses

• Over-the-counter (OTC) pain relievers like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol)

Keep in mind, this may make you feel better, but it won't actually solve your underlying problem. You'll still need to get medical care if your swollen lymph nodes don't go away.

When to see a healthcare professional

Swollen lymph nodes usually get better on their own. See a healthcare professional if your lymph nodes remain swollen for more than a few weeks.

Sometimes, though, you may need to have your lymph node swelling evaluated sooner. Notify a healthcare professional if your swollen lymph nodes have any of the following signs:

• Hard or rubbery

• Red and tender

• Located in the area just above the collarbone

• Fixed in place instead of rolling underneath the fingers

• Larger than 1 cm in diameter in adults or 3 cm in children

You also want to get medical care if the lymph node swelling is accompanied by:

• High fevers that persist or recur

• Stomach pain that persists or recurs

• Unexplained weight loss

• Drenching night sweats

Frequently asked questions