Lymph nodes are small glands that filter lymph, the clear fluid that circulates through the lymphatic system. They become swollen in response to infection and tumors.
Lymphatic fluid circulates through the lymphatic system, which is made of channels throughout your body that are similar to blood vessels. The lymph nodes are glands that store white blood cells. White blood cells are responsible for killing invading organisms.
The lymph nodes act like a military checkpoint. When bacteria, viruses, and abnormal or diseased cells pass through the lymph channels, they are stopped at the node.
When faced with infection or illness, the lymph nodes accumulate debris, such as bacteria and dead or diseased cells.
Lymph nodes are located throughout the body. They can be found underneath the skin in many areas including:
- in the armpits
- under the jaw
- on either side of the neck
- on either side of the groin
- above the collarbone
Lymph nodes swell from an infection in the area where they are located. For example, the lymph nodes in the neck can become swollen in response to an upper respiratory infection, like the common cold.
What causes the lymph nodes to swell?
Lymph nodes become swollen in response to illness, infection, or stress. Swollen lymph nodes are one sign that your lymphatic system is working to rid your body of the responsible agents.
Swollen lymph glands in the head and neck are normally caused by illnesses such as:
- ear infection
- the cold or flu
- sinus infection
- HIV infection
- infected tooth
- mononucleosis (mono)
- skin infection
- strep throat
More serious conditions, such as immune system disorders or cancers, can cause the lymph nodes throughout the body to swell. Immune system disorders that cause the lymph nodes to swell include lupus and rheumatoid arthritis.
Any cancers that spread in the body can cause the lymph nodes to swell. When cancer from one area spreads to the lymph nodes, the survival rate decreases. Lymphoma, which is a cancer of the lymphatic system, also causes the lymph nodes to swell.
Some medications and allergic reactions to medications can cause the lymph nodes to swell. Antiseizure and antimalarial drugs can also cause lymph nodes to swell.
Other causes of swollen lymph nodes include:
- cat scratch fever
- ear infections
- Hodgkin’s disease
- metastasized cancer
- mouth sores
- non-Hodgkin’s lymphoma
Detecting swollen lymph nodes
A swollen lymph node can be as small as the size of a pea and as large as the size of a cherry.
Swollen lymph nodes can be painful to the touch, or they can hurt when you make certain movements.
Swollen lymph nodes under the jaw or on either side of the neck may hurt when you turn your head in a certain way or when you’re chewing food. They can often be felt simply by running your hand over your neck just below your jawline. They may be tender.
Swollen lymph nodes in the groin may cause pain when walking or bending.
Other symptoms that may be present along with swollen lymph nodes are:
If you experience any of these symptoms, or if you have painful swollen lymph nodes and no other symptoms, consult your doctor. Lymph nodes that are swollen but not tender can be signs of a serious problem, such as cancer.
In some cases, the swollen lymph node will get smaller as other symptoms go away. If a lymph node is swollen and painful or if the swelling lasts more than a few days, see your doctor.
At the doctor’s office
If you’ve recently become ill or had an injury, make sure to let your doctor know. This information is vital in helping your doctor determine the cause of your symptoms.
Your doctor will also ask you about your medical history. Since certain diseases or medications can cause swollen lymph nodes, giving your medical history helps your doctor find a diagnosis.
After you discuss the symptoms with your doctor, they will perform a physical examination. This consists of checking the size of your lymph nodes and feeling them to see if they’re tender.
After the physical examination, a blood test may be administered to check for certain diseases or hormonal disorders.
If necessary, the doctor may order an imaging test to further evaluate the lymph node or other areas of your body that may have caused the lymph node to swell. Common imaging tests used to check lymph nodes include CT scans, MRIs, X-rays, and ultrasound.
In certain cases, further testing is needed. The doctor may order a lymph node biopsy. This is a minimally invasive test that consists of using thin, needle-like tools to remove a sample of cells from the lymph node. The cells are then sent to a laboratory where they are tested for major diseases, such as cancer.
If necessary, the doctor may remove the entire lymph node.
How are swollen lymph nodes treated?
Swollen lymph nodes may become smaller on their own without any treatment. In some cases, the doctor may wish to monitor them without treatment.
In the case of infections, you may be prescribed antibiotics or antiviral medications to eliminate the condition causing the swollen lymph nodes. Your doctor might also give you medications such as aspirin and ibuprofen (Advil) to combat pain and inflammation.
Swollen lymph nodes caused by cancer may not shrink back to normal size until the cancer is treated. Cancer treatment may involve removing the tumor or any affected lymph nodes. It may also involve chemotherapy to shrink the tumor.
Your doctor will discuss which treatment option is best for you.