What causes swollen lymph nodes?

The most common causes of swollen lymph nodes are viral infections, such as the common cold, and bacterial infections, such as strep throat. Immune system disorders and some types of cancer can also lead to swollen lymph nodes.

Common infectious causes of swollen lymph nodes

The more common infectious causes of swollen lymph nodes include viral and bacterial infections. Some of these conditions caused by bacteria are associated with serious and potentially life-threatening complications if they are not treated with antibiotics:

  • Common cold (viral respiratory infection)

  • Ear infection

  • Infected tooth (abscessed tooth)

  • Infected wound

  • Influenza (flu)

  • Measles (contagious viral infection also known as rubeola)

  • German measles (contagious viral infection also known as rubella)

  • Mononucleosis (viral infection)

  • Mumps (viral infection of the salivary glands in the neck)

  • Strep throat (bacterial throat infection)

  • Tonsillitis (inflammation of the tonsils in the back of the throat)

Other infectious causes of swollen lymph nodes

Less common, but potentially life-threatening infectious diseases that cause swollen lymph nodes include:

  • AIDS (caused by HIV infection)

  • Cat scratch fever (bacterial infection from being scratched or bitten by a cat that carries the bacteria)

  • Cellulitis (bacterial skin infection)

  • Syphilis (sexually transmitted disease caused by bacteria)

  • Toxoplasmosis (parasitic infection)

  • Tuberculosis (serious infection affecting the lungs and other organs)

Other noninfectious causes of swollen lymph nodes

Swollen lymph nodes can also be caused by noninfectious disorders such as:

  • Chronic fatigue syndrome

  • Lymphatic obstruction (blockage in the lymph system)

  • Sarcoidosis (inflammatory disease most commonly affecting the lungs, skin and eyes)

Autoimmune diseases that can cause swollen lymph nodes

Swollen lymph nodes can also be caused by problems with the immune system itself, such as:

  • Juvenile rheumatoid arthritis

  • Rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation)

  • Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

Cancers that can cause swollen lymph nodes

The most notable life-threatening diseases that cause swollen lymph nodes are different types of cancers including:

  • Hodgkin lymphoma (Hodgkin’s disease)

  • Leukemia

  • Melanoma
  • Metastasized cancer that has traveled to the lymph nodes

  • Non-Hodgkin lymphoma

  • Oral, mouth or larynx cancer

What are the potential complications of swollen lymph nodes?

Viral infections that cause swollen lymph nodes can often be treated with self-care measure at home. The swelling will go away as your body fights off the infection. Self-care measures include rest, drinking lots of fluids, warm compresses, and over-the-counter pain relievers.

For persistent or chronic swelling, redness and pain, it is important to seek medical care because these are symptoms of a possible bacterial infection. Bacterial infections will need to be treated with antibiotics and the treatment plan designed by your doctor. Left untreated, a localized bacterial infection can spread to the blood and vital organs and quickly become life threatening. In addition, untreated or poorly controlled lymphoma, leukemia, and other cancers can spread and result in loss of life.

Over time, swollen lymph nodes can lead to serious complications including:

  • Formation of an abscess

  • Rheumatic fever (inflammatory disease that can develop as a complication of strep throat)

  • Scarlet fever (rash caused by strep infections)

  • Spread of cancer

  • Spread of infection to the blood (septicemia or bacteremia)

  • Toxic shock syndrome


  1. Swollen lymph nodes. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/003097.htm.
  2. Understanding Microbes in Sickness and in Health. National Institute of Allergy and Infectious Diseases.  http://www.niaid.nih.gov/topics/microbes/documents/microbesbook.pdf.
  3. Non-Hodgkin Lymphoma. National Cancer Institute. http://www.cancer.gov/cancertopics/types/non-hodgkin.
  4. Sarcoidosis: Symptoms. National Jewish Health. http://www.nationaljewish.org/healthinfo/conditions/sarcoidosis/symptoms.aspx.

What are swollen lymph nodes?

Swollen lymph nodes are enlarged lymph nodes, which are very small clusters of immune cells that function as part of the body’s immune system. There are more than 600 lymph nodes throughout the body, but the ones most frequently enlarged or swollen are found in the neck, under the chin, in the armpits, and in the groin.

Swollen lymph nodes are also known as lymphadenitis, lymphade... Read more about swollen lymph nodesintroduction


What other symptoms might occur with swollen lymph nodes?

Swollen lymph nodes often occur with other symptoms that vary in severity depending on the underlying disease, disorder or condition.

Symptoms that may occur along with swollen lymph nodes

Swollen lymph nodes may occur with other symptoms including:

  • Bleeding gums
Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: May 7, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.