Swollen Lymph Nodes: Causes, Symptoms & Treatment

The lymphatic system is a vital part of the immune system, consisting of a network of vessels, lymph nodes, and other organs that help the body fight infections and maintain fluid balance. Lymph nodes are small bean-shaped structures that act as filters, trapping harmful substances like bacteria, viruses, and abnormal cells.

They can swell due to infections, inflammation, or injury as they fight pathogens and aid healing. Discovering a small lump on the neck can often be linked to swollen lymph nodes, which are usually harmless and self-resolving. However, persistent or significantly enlarged nodes—especially when accompanied by fever, night sweats or unexplained weight loss—may indicate a more serious issue such as an infection, immune disorder or, in rare cases, cancer.

What Are Lymph Nodes?

Lymph nodes function as surveillance hubs, filtering lymphatic fluid and trapping pathogens like bacteria, viruses, and abnormal cells. Within the lymph nodes, specialised immune cells—including lymphocytes and macrophages—work to identify and destroy these harmful invaders. By triggering an immune response, lymph nodes play a key role in protecting the body from infection and supporting overall health.

Lymph nodes are distributed throughout the body. Common locations where this swelling is frequently observed include:

• Neck (cervical lymph nodes)
• Under the chin (submandibular lymph nodes)
• Armpits (axillary lymph nodes)
• Groin (inguinal lymph nodes)
• Above the collarbone (supraclavicular lymph nodes)
• Back of the head, just above the hairline (occipital lymph nodes)

These areas are often checked during physical exams, especially when swelling is suspected, as they are close to the skin and easy to assess. Swollen lymph nodes, a condition known as lymphadenopathy, are usually a sign that the body is responding to a nearby infection, inflammation, or injury.

For example, a throat infection might cause swelling in the cervical lymph nodes. Other causes include immune conditions like lupus or rheumatoid arthritis, and in rare cases, cancers like lymphoma. While most swelling goes away as the issue improves, a healthcare provider should evaluate persistent or unusual swelling.

What Are the Common Causes of Swollen Lymph Nodes?

Swollen lymph nodes can result from infections, immune-related conditions, and cancer-related causes.

Infections

Infections are the most common cause of swollen lymph nodes, with the swelling often localised near the site of infection. Specific examples include:

• Viral Infections: Common colds, influenza, and mononucleosis (mono) are frequent culprits, often resolving within 10 to 14 days, with swelling subsiding as the infection clears, though it may take weeks to disappear completely.
• Bacterial Infections: Conditions like strep throat and dental infections can cause swelling, particularly in the neck, and may require antibiotics for treatment.
• Fungal and Parasitic Infections: Though less common, these can also cause lymph node enlargement and may require targeted antifungal or antiparasitic treatment.

Immune-Related Conditions

Certain autoimmune and inflammatory diseases can cause generalised lymph node swelling, indicating systemic involvement. Some of these conditions include:

• Lupus: A chronic inflammatory disease affecting multiple organs, including joints, skin, kidneys, blood cells, heart, and lungs, leading to widespread lymph node enlargement.
• Rheumatoid Arthritis: A chronic inflammatory disorder primarily affecting the joint-lining tissue (synovium), which can cause lymph node swelling as part of the immune response.
• Sarcoidosis: Characterised by the growth of tiny inflammatory cell groups (granulomas), most often in the lungs and lymph nodes, leading to chronic swelling.

Cancer-Related Causes

Cancer can cause lymph node swelling, either as a primary malignancy or through metastasis.

• Lymphoma: A cancer originating in the lymph system, often presenting with painless, rubbery lymph node enlargement, particularly in the neck, armpits, or groin.
• Leukaemia: Cancer of the blood-forming tissues, including bone marrow and the lymph system, which can lead to generalised lymph node swelling.
• Metastatic Cancers: Cancers that have spread from other body parts (e.g., breast, lung, or melanoma) to the lymph nodes, often causing hard, fixed nodes that do not move under the skin.

What Accompanying Symptoms Could You Experience?

Swollen lymph nodes can come with various symptoms, depending on the cause. You might notice:

• Swelling under the skin, often felt as small, firm lumps in areas like the neck, under the chin, armpits, or groin
• Tenderness or pain in the area, which can hurt more when you move, like walking (for groin nodes) or turning your head (for neck nodes)
• Redness or warmth over the swollen nodes, especially if there is an infection
• General symptoms like fever, sore throat, fatigue, night sweats, runny nose, or cough, which often suggest an infection like a cold or flu

If the swelling is painless and the nodes feel hard or fixed, it might be something more serious. This is sometimes linked to cancers like breast cancer (under the arm) or lymphoma (near the collarbone). Always consult a doctor if you are unsure.

How Doctors Diagnose Swollen Lymph Nodes

Doctors use several methods to figure out why your lymph nodes are swollen:

• Medical History and Physical Exam: Your doctor will first ask when the swelling began and if it is tender. They will also carefully examine the nodes, noting their size, location, and texture (soft, firm, or rubbery). This initial assessment provides important clues about the cause.
• Blood Tests: A complete blood count (CBC) may be used to look for signs of infection or other conditions like leukaemia or HIV.
• Imaging: Ultrasound, CT scans, or MRI may be used to view the lymph nodes and surrounding areas, especially if cancer is suspected.
• Lymph Node Biopsy: If the cause is not clear or cancer is a concern, a biopsy may be required, where a sample or the whole node will be taken to test for diseases like cancer.

Doctors will also check for warning signs, such as nodes larger than 1 cm, very painful or fixed nodes, or symptoms like unexplained weight loss, fever, or night sweats, which may suggest a more serious condition.

What Are the Treatments for Swollen Lymph Nodes?

Treatment depends on what is causing the swelling:

• If caused by infections:
  • For viral infections (like colds), the approach is typically supportive. Focus on rest and staying well-hydrated. You can use over-the-counter pain relievers such as ibuprofen to manage any discomfort. It is important to remember that antibiotics will not be effective against viral infections.
  • For bacterial infections (like strep throat), antibiotics are needed.
• If due to autoimmune conditions: Treatment focuses on managing the underlying disease, often with anti-inflammatory drugs or other therapies.
• If cancer is the cause: Options include chemotherapy, radiation therapy, targeted therapy, immunotherapy, or surgery to remove affected nodes.

For pain relief at home, applying a warm compress to the swollen area can offer comfort, though it will not reduce the size of the nodes themselves. If the swelling is localised and caused by a viral infection, it will often resolve on its own as your body recovers.

When Should You See a Doctor?

It is important to seek medical attention if you notice any swollen lymph nodes or, simply put, any lumps on your neck, especially if they persist for more than two weeks. Swollen lymph nodes are usually a sign that your immune system is fighting an infection, such as a cold, flu, or sore throat. They often return to normal within one to two weeks. However, in some cases, they can signal a more serious condition, like cancer. If you are unsure or concerned about any swelling, do not wait. Make an appointment with our specialist for timely diagnosis and expert care.

Our Thyroid Surgeon

Dr Ranjiv Sivanandan
MBBS, FRCSEd, MMEd (Surgery), FAMS
American Head & Neck Society (Stanford University, USA)

Dr Ranjiv Sivanandan is a Specialist Board Certified General Surgeon who has devoted his career to the practice and development of thyroid and head & neck surgery. He is recognised for his expertise in diagnosing and treating conditions involving swollen lymph nodes in the neck and surrounding regions. Dr Ranjiv pioneered robotic surgery in the region, performing the first robotic thyroidectomy in Singapore in 2010 and the first robotic neck dissection in Southeast Asia in 2011.