Lymph nodes are small, round structures that play a vital role in the body's immune system. Swollen lymph nodes are also known as swollen glands.
In this article, we look at the causes of swollen lymph nodes, when to see a doctor, and treatment options.
What are swollen lymph nodes?
The immune cells in lymph nodes help fight infection.
The lymph nodes collect and filter fluids, waste materials, and harmful germs. The human body has hundreds of lymph nodes. The main lymph nodes that people may see or feel are found:
- under the jaw
- on each side of the neck
- under the armpits
- on either side of the groin
Lymph fluid flows in and out of the lymph nodes throughout the body before finally making its way back to the chest. While doing so, it collects and traps harmful matter, such as bacteria, viruses, and bodily waste products. The lymph nodes filter the fluid and release it back into the bloodstream together with salts and proteins.
Lymph nodes also contain immune cells that help fight infection by attacking the germs that the body's lymph fluid has collected.
The lymph nodes may swell when a person has a temporary infection. The swelling occurs as a result of immune cell activity in the lymph nodes.
The location of the swelling often relates to the affected area. For example, an ear infection may cause swollen lymph nodes near the ear, while someone with an upper respiratory tract infection may notice swollen lymph nodes in their neck.
How to check lymph nodes for swelling
People can check whether their lymph nodes are swollen by gently pressing around the area, such as the side of the neck.
Swollen lymph nodes will feel like soft, round bumps, and they may be the size of a pea or a grape. They might be tender to the touch, which indicates inflammation. In some cases, the lymph nodes will also look larger than usual.
Lymph nodes appear in parallel on both sides of the body. People can check the nodes on each side and compare them to see if one is larger than the other, which is likely to indicate swelling.
Many people with swollen glands also experience pain while making sudden or strained movements. Such movements include sharply turning the neck, bobbing the head, or eating foods that are difficult to chew.
Swollen lymph nodes often occur alongside other symptoms. These vary depending on the underlying problem but may include a sore throat, cough, or flu-like symptoms.
Causes of swollen lymph nodes
Many different conditions cause the lymph nodes to swell, particularly the nodes in the head and neck. These conditions include autoimmune disorders, specific types of cancer, and common infections, such as the flu. Certain medications, such as antimalarials and antiseizure drugs, can also cause swelling.
Most people have localized lymphadenopathy, in which only the lymph nodes in one particular area of the body swell up. When more than one region swells, this is called generalized lymphadenopathy, and it usually signifies a systemic, or body-wide, disease that may require medical attention.
In the following sections, we discuss the possible causes of swollen lymph nodes in more detail.
Colds and flu may cause swollen lymph nodes.
The infections that can cause swollen lymph nodes are mostly viral. Common infections include:
- the common cold
- the flu
- sinus infections
- tooth or gum infections
- staph infections
- strep throat
- skin infections
- fungal infections
More severe infections that can cause swelling in one or multiple lymph node areas include:
Cat scratch fever, which is also called cat scratch disease, can cause localized lymph node swelling in the area near the cat scratch.
Immune system disorders
Immune disorders that can cause swollen lymph glands include:
Much less commonly, swollen lymph nodes can also indicate a malignancy, or cancer, including:
Certain risk factors make a person more likely to have a malignant lymph problem, such as lymphoma. These include:
- being aged 40 years or older
- being male
- having white skin
People with a malignant lymph node may notice that the node feels hard or rubbery. They may also experience systemic symptoms, such as fever, night sweats, and unexplained weight loss.
Swelling in the groin lymph nodes
Recurring infections, lower body infections, and injury to the legs can also cause swollen lymph nodes in the groin.
When to see a doctor
In many cases, swelling reduces and then disappears within 2 to 3 weeks once the body has successfully fought the infection. If the problem persists for longer than a couple of weeks, it might warrant a visit to the doctor.
Other reasons to visit the doctor include:
- a lymph node that feels hard or rubbery to the touch
- a node that does not move freely
- a node that is an inch or more in diameter
- swollen lymph nodes that accompany night sweats, abdominal pain, unexplained weight loss, or a high fever
A doctor can often diagnose the cause of swollen lymph nodes by carrying out a physical examination with a focus on the affected area and by discussing the person's symptoms and medical history.
However, they may also order medical tests to determine the cause of the swelling. These tests may include a routine blood test to look for signs of infection.
Imaging tests can help a doctor look closely at the lymph nodes and the surrounding structures of the body. Imaging tests include:
If the swelling continues for several weeks or a person has other warning signs, a doctor may recommend a lymph node biopsy. During this procedure, the doctor will numb the area, make a small cut, and remove a section of lymph node tissue to send to a laboratory for examination under a microscope.
Alternatively, they may opt for fine needle aspiration, which involves using a needle to remove some cells from the lymph node for analysis.
How to treat swollen lymph nodes
Drinking plenty of fluids will help reduce symptoms that an infection may cause.
Lymph node swelling will usually disappear once the infection clears. The swelling may also go away when the person takes prescribed medications, such as antibiotics or antivirals.
Doctors may prescribe anti-inflammatory medication if a person has tissue swelling.
If an underlying medical condition is responsible for the lymph nodes swelling, treating this condition should reduce the swelling.
Common home remedies to treat the symptoms of swollen lymph nodes include:
- taking over-the-counter pain medicines, such as acetaminophen or ibuprofen
- applying a warm wet compress to the affected area
- drinking plenty of fluids, such as water and fresh juices
- resting to help the body recover from the illness
Swollen lymph nodes are usually a symptom of another condition, such as an infection, and they tend to resolve on their own within several weeks.
It is best to consult a doctor if swollen lymph nodes persist for longer than 3 weeks or occur alongside other symptoms, such as high fever, abdominal pain, or night sweats. The cause of the swelling will determine the treatment.