The Causes of Swollen Lymph Nodes

Medical consultation Doctor examining the thyroid gland of a patient.
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When people refer to swollen glands, most of the time they are actually referring to swollen lymph nodes. An infection, especially a viral infection such as the common cold, is the most common cause of swollen lymph nodes. Strep throat and mononucleosis also commonly produce swollen nodes. Both bacterial and viral infections can cause lymph nodes to swell, and it doesn’t have to be an upper respiratory infection--ear infections, skin and wound infections, and tooth abscesses are all common infections leading to swollen lymph nodes.

Are Lymph Nodes Really Glands?

No, not really. True glands secrete something, such as saliva, sweat, tears or milk. Or they release hormones, like the thyroid, pituitary, testes, and ovaries. Lymph nodes are a part of the immune system. And, while they do release substances that help to fight infections, they are different enough from what are traditionally considered the glands of the body that they get their own category.

So what's the connection between lymph nodes and glands? In the neck, lymph nodes and salivary glands may be located very closely to one another. Mumps used to produce a painful swelling of the salivary glands much more commonly than it does today. So perhaps the term swollen glands is interesting from this historical standpoint, and it's still a term that is used today to refer to swollen lymph nodes.

To learn more about lymph nodes, their normal size and potential connections to cancer or immune disorders, visit the lymph node learning hub.

How Can I Tell if It’s a Lymph Node or Something Else?

It's not always easy, so see a doctor to make this determination. There is a part of one of the neck muscles, for instance, that is sometimes confused for a lymph node, even by medical students. What's more, small bumps under the skin are fairly common and may be due to any number of different causes.

Some common lumps that aren't lymph nodes include sebaceous cysts and lipomas. Sebaceous cysts are collections of skin gunk beneath the skin, while lipomas are growths of fat cells inside a thin capsule, usually just below the skin.

Your doctor knows the patterns of lymph drainage, along with the typical locations for lymph nodes. By seeing you and doing the physical exam,  your doctor will often be able to quickly tell the difference between common lumps and bumps, normal lymph node swelling or something more concerning.

Do Lymph Nodes Ever Swell for No Apparent Reason?

Sometimes the reasons for lymph node swelling are never identified--so, the answer is technically yes. One should not assume, however, that a lymph node is harmless and will go away on its own. If you have signs and symptoms along with swollen nodes, sometimes further testing is needed right away.

If you have a swollen lymph node and no other symptoms, and if you and your doctor can’t pin down the cause right away, you might opt to watch and wait for a bit. However, if a swollen lymph node defies explanation over weeks or as long as a month, a biopsy or further specific testing is needed.

I Have a Swollen Lymph Node. Is it Lymphoma?

Probably not, but it's possible.

See your doctor, who will look for the most common causes of swollen lymph nodes before considering less common causes. Most people who come to medical attention because of swollen lymph nodes have a cause that can be easily identified and is either benign or will take care of itself in time.

What Kinds of Things Cause Swollen Lymph Nodes?

Here is an old memory device that some doctors may still recall. Hodgkin's disease is just one possibility, but it serves as the skeleton for this mnemonic. It doesn't cover everything, but it is useful for thinking about diseases associated with lymphadenopathy, or swollen lymph nodes.

Generalized lymphadenopathy means there are more than two nodes involved from different areas. As you can see, there are many possible causes:

H. Hematologic: Hodgkin’s disease, leukemia, and non-Hodgkin’s lymphoma

O. Oncologic: Metastasis to lymph node, malignant melanoma

D. Dermatopathic lymphadenitis: swollen lymph nodes that drain a patch of skin that has been disrupted or irritated

G. Gaucher’s disease: a rare genetic disease

K. Kawasaki’s disease: a rare autoimmune disease involving the blood vessels and inflammation

I. Infections: bacterial, viral, and parasitic

N. Niemann–pick disease: a genetic disease that involves metabolism

S. Serum sickness: an immune response to certain medications or treatments

D. Drug reaction: response to certain drugs

I. Immunological disease: for example, rheumatoid arthritis and lupus

S. Sarcoidosis: an inflammatory disease that can affect different parts of the body

E. Endocrine: hyperthyroidism

A. Angioimmunoplastic lymphadenopathy: this is an old term; currently considered a lymphoma.

S. Systemic lupus erythematosus (lupus, or SLE)

E. Eosinophilic granulomatosis: a systemic disease involving allergic and inflammatory manifestations

A Word from Verywell

Swollen lymph nodes in most cases are adaptive responses -- that is, your body is doing what it is supposed to be doing, in order to fight an infection, for instance. However, lymph node swelling, whether it's a single lymph node or multiple lymph nodes that are enlarged, may also be the only sign of lymphoma, in some cases and in some individuals. These two facts combined account for the standard approach taken by most doctors. That is, to avoid over-reacting or leaping into a lymphoma workup at the first sighting of a swollen lymph node; but at the same time, to not let a persistently swollen lymph node remain indefinitely without an appropriate investigation, which may include biopsy in the case of exploring the possibility of lymphoma or some other malignancy.

Sources:

Lymphadenopathy and Malignancy.

Mnemonics In Internal Medicine & Pediatrics. Parmar HB. B. Jain Publishers, Jan 1, 2002.

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