The Common Causes of Swollen Lymph Nodes

What are Lymph Nodes?

One of the most common reasons why people, especially children, visit the physician is swollen lymph nodes. Also called glands, lymph nodes are present throughout the body and play an important role in the body's ability to fight viruses, bacteria, and other germs. The most common spots in the body where these are present include the groin, armpit, neck, under the jaw, behind the ears, and on the back of the head. Let's have a brief look at why people usually get swollen glands.

Causes of Lymph Nodes Swelling

The most common causes of swelling in the glands are infections, where the swelling may appear suddenly and may also be painful. If the swelling occurs slowly, a cancer may be the reason. The most common causes of swollen glands include the following.


Cells in the lymph nodes are responsible for capturing bacteria and viruses and then breaking them down. During an infection, types of white blood cells called lymphocytes present in the glands tend to multiply rapidly in order to fight these pathogens. This makes the lymph nodes expand and leads to the condition often referred to as swollen glands.

A viral infection, such as the common cold is the most common reason of enlarged glands. However, there are bacterial and parasitic infections that can also cause this condition. These other infections include strep throat, tonsillitis, mumps, measles, ear infections, or wound infections.

Gum and tooth diseases such as gingivitis and impacted or abscessed tooth and mouth sores are also likely causes.

Other infections that can cause inflammation in the lymph nodes include tuberculosis and mononucleosis. Syphilis and other sexually transmitted diseases can also lead to this condition.

Your pets can also be responsible for causing this swelling. A bacterial infection from a cat scratch or bite and a parasitic infection due to contact with the feces of an infected cat are possible causes.

Immune System Disorders

Lymph nodes are an important organ of the immune system of the body. In autoimmune disorders, the immune system begins to attack its own cells mistaking it to be a pathogen and causes chronic inflammation in the various tissues of the body. These are one of the main immunologic causes of swollen and tender glands and include lupus and rheumatoid arthritis. Lupus affects the skin, kidneys, blood cells, heart, and lungs of the individual, whereas rheumatoid arthritis attacks the synovial tissue around the joints. Besides autoimmune disorders, the Human Immunodeficiency Virus (HIV), the virus that causes AIDS and makes the immune system fail can also lead to enlarged glands.


There are certain cancers that are also responsible for inflamed glands. When cancer occurs in the blood-forming tissues of the body, it is called leukemia. Lymph nodes are linked to each other through the lymphatic vessels and leukemia can affect the tissues of the lymphatic system leading to inflammation in the glands.

Lymphoma is a cancer that originates in the lymph tissues of the lymph nodes and like all tumors, the uncontrolled and abnormal cells division causes swelling in the affected gland.

Metastasized cancers spread from other parts of the body to the lymph nodes. Once it affects the tissues of a particular gland, it tends to form a tumor in the area and cause inflammation.


Another cause of swelling in the lymph nodes is medication. There are certain medications, such as phenytoin prescribed for preventing seizures that can be the reason for this condition. Vaccinations such as ones for typhoid or malarial immunization have also been found to lead to enlarged glands. Vaccinations make the glands swell for much the same reason that infection does. Even though in the case of vaccination there is no actual infection, the immune system is responding to the vaccine and immune cells will congregate in the glands.

When to Consult a Physician

As you can see, there are many causes of swollen lymph nodes. In most cases, the soreness disappears in two to three days. However, if it has been several weeks since the infection has cleared and the gland has not returned to its normal size or if it is larger than one centimeter in diameter in a child, a physician should be consulted. A medical professional will identify the cause of the enlarged gland and prescribe the right treatment, depending on its location.


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