Swollen lymph nodes facts
Lymph nodes are important part of the immune system.
Lymph nodes are located throughout the body, but visible and palpable only when they are enlarged or swollen.
Lymph nodes are regional, and each group of them corresponds to a particular region of the body and reflects abnormalities in that region.
In general, infections are the most common causes of lymph node enlargement. Other common causes include inflammation and cancers.
Not all swollen lymph nodes are abnormal.
What are lymph nodes?
Lymph nodes are an important component of the body's immune system and help in fighting infections.
They are small, soft, round or oval structures that are found throughout the body and are connected to each other in chain-like (lymphatic chains) fashion by channels similar to blood vessels. Each individual lymph node is covered by a capsule made up of connective tissue.
Within the capsule, lymph nodes contain certain kinds of immune cells. These cells are mainly lymphocytes, which produce proteins that capture and fight viruses and other microbes, and macrophages, which destroy and remove the captured material.
Where are the lymph nodes located in the body?
Lymph nodes are located throughout the body. Some are directly under the skin while others are deep inside the body. Even the most superficial (close to the skin) lymph nodes are usually not visible or palpable (felt by touching), unless they are swollen or enlarged for some reason.
They are connected to each other by loosely bound lymphatic vessels. Lymph nodes generally coalesce in different regions in the body where they are responsible for filtering the blood and performing their immunologic function for that particular area of the body. Fluid from the lymphatic vessels eventually feeds into the venous system (veins) in the body.
What are the causes of swollen lymph nodes?
There are may causes for swollen lymph nodes, sometimes referred to as "swollen glands" (lymphadenopathy or lymphadenitis). In general, lymph nodes become swollen when they are active either due to an infection, inflammation, or cancer.
Infections
Infections are the most common causes of swollen lymph nodes. Common infectious causes of swollen lymph nodes are viral, bacterial, parasites, and fungal. The most common cause of swollen lymph nodes is viral upper respiratory infections such as the common cold.
Viruses
Infectious mononucleosis (mono)
Chickenpox
Measles
HIV
Herpes
Common cold viruses
Adenovirus
Many other viruses
Bacteria
Streptococcus
Staphylococcus
Cat scratch disease
Syphilis
Tuberculosis
Chlamydia
Other sexually transmitted diseases
Parasites
Toxoplasmosis
Leishmaniasis
Fungal
Coccidiomycosis
Histoplasmosis
Inflammation
Inflammatory and immunologic causes of swollen lymph nodes include diseases such as rheumatoid arthritis and lupus as well as sensitivity to some medications.
Cancer
Many cancers can also cause swelling of lymph nodes. These may be cancers that originate from the lymph nodes or blood cells such as lymphomas and leukemias. They may also be cancers that spread from another organ in the body (metastatic cancers). For example, breast cancer may spread to the nearest lymph nodes in the underarm (axilla), or lung cancer may spread to the lymph nodes around the collar bone.
Other causes of swollen lymph nodes
There are many other less common causes of swollen nodes, such as genetic lipid storage diseases, transplant graft rejections, sarcoidosis, and many other conditions.
It is also important to mention that swollen lymph nodes are not always a sign of an underlying disease. Sometimes they can be normal. For example, small (less than 1 centimeter), flat lymph nodes under the jaw (submandibular lymph nodes) in healthy children and young adults or small (up to 2 centimeters), groin lymph nodes (inguinal lymph nodes) in young individuals may be normal.
In many instances, a definitive cause for swollen lymph nodes may not be determined even after performing through examination and testing
What are the symptoms of swollen lymph nodes?
Symptoms of swollen lymph nodes vary widely. A person could be completely free of symptoms (asymptomatic) and only found when they are noted by a doctor during a general physical examination.
Sometimes, swollen lymph nodes can be extremely tender, painful, and disfiguring.
More importantly, other symptoms related to an underlying disease that accompany the lymph node swelling may be more significant and clinically relevant than the lymph node swelling alone. For instance, symptoms such as:
fever,
night sweats,
weight loss,
or evidence of local infections (toothache, sore throat) may provide valuable clues in determining the cause of lymph node swelling
How are swollen lymph nodes diagnosed?
Swollen lymph nodes closer to the surface of the body are generally diagnosed by a doctor's examination and feeling for areas known to have coalescence of lymph nodes, for example, swollen lymph nodes under the arms (axillary lymph nodes), swollen lymph nodes in the sides of the neck (cervical lymph nodes), or swollen lymph nodes in the groin (inguinal lymph nodes). These swollen lymph nodes can be seen and felt easily.
Other times, deeper lymph nodes could be seen on imaging studies, such as CT scan (computed tomography), of different parts of the body.
Tonsils in the back of the throat are also lymph nodes, and they are the most visible ones in the body.
Diagnosing the cause of swollen lymph nodes may be challenging at times. The most important component of evaluating a swollen lymph node is a thorough medical history and a complete physical examination by a doctor. The doctor may ask you about symptoms such as sore throat, fever and chills, fatigue, weight loss, a complete list of medications, sexual activity, vaccination history, recent travels, the patient's own and his/her family's previous history of cancers if any, and so forth.
A group of lymph nodes in a particular area of the body react to disturbances in that general region. If there is a specific infection in the region of the swollen lymph nodes, that may be the most likely cause of swelling. For instance, an infection of the leg or some sexually transmitted diseases can cause swelling of the lymph nodes in the groin area.
Physicians usually examine the lymph nodes by feeling them and characterize them based upon what the lymph nodes feel like. They could be characterized, for example, as:
Large or small
Tender or non-tender
Fixed or mobile
Hard or soft
Firm or rubbery
These characteristics can be useful in suggesting the cause of the lymph node swelling. For example, a hard, nontender, nonmoveable lymph node may be more characteristic of a cancer spread to that node. On the other hand, a soft, tender, moveable lymph node could more likely represent an infection.
If the enlarged lymph nodes are suspected to be related to a cancer, then a biopsy of the lymph node may determine the cancer type. For example, a swollen lymph node around the collar bone (supraclavicular lymph node), may signify lung cancer in a person who may have other clinical clues suggestive of lung cancer
What is the treatment for swollen lymph nodes?
There is no specific treatment for swollen lymph nodes. Generally, the underlying cause needs to be treated, which may result in the resolution of the swollen lymph node.
Treating an infection causing the swollen lymph node, for example, will result in the lymph node swelling to subside. If the swollen lymph node is due to a cancer of the lymph node (lymphoma), then the swelling will shrink after treating the lymphoma.
When should I see the doctor for swollen lymph nodes?
If swollen lymph nodes are associated with fevers, night sweats, or weight loss, and the patient does not have any obvious infection, he/she may need a through evaluation by a doctor.
Also, people who were appropriately treated for an infection but have persistent swollen lymph nodes may need to see their doctor.
If a patient has a known cancer, or were treated for one in the past and he/she notices new lymph nodes in the general area of the cancer, he/she may need to notify a physician
What are the common lymph nodes that may become swollen?
There are many adult lymph nodes in varying parts of the body that may become swollen for different reasons. Many people can usually see swollen lymph nodes on the neck, behind the ear, under the jaw, above the collar bone, under the arms, and around the groin.
Swollen lymph nodes on the side of the neck or under jaw are the most common. They may represent an infection around that area, such as a tooth infection or abscess, throat infection, viral illness, or upper respiratory infection. Most of the causes of swollen lymph nodes in this area are benign (noncancerious); however, sometimes, swelling of these lymph nodes may also suggest a cancer in the head and neck area.
Swollen lymph nodes behind the ear may correspond to an infection around the scalp or possibly a conjunctival (eye) infection. The most common cause of swollen scalp lylmph nodes are skin conditions affecting the scalp, such as dandruff (sebhorrheic dermatitis).
The lymph nodes in the underarm (axilla) are anatomically important in breast cancer. They are often checked physically in patients undergoing investigation for breast cancer. They also play an important role in staging (determining the extent) and prognosticating (predicting the outcome) of breast cancer during removal of the cancer tissue from the breast. These lymph nodes can also become reactive and enlarge due to a trauma to or an infection of the arm on the same side.
Enlarged lymph nodes above the collar bone (supraclavicular lymphadenopathy) are always considered to be abnormal. These generally suggest a cancer of or an infection in the region close by. Examples of these may include lung infection, lung cancer, lymphoma in the chest cavity, or breast cancer. Occasionally more distant cancers may seed these lymph nodes, such as genital cancers or colon cancer. Some inflammatory causes of the swollen lymph nodes above the collar bone (clavicle) can include tuberculosis or sarcoidosis.
Swollen lymph nodes in the groin may be normal in young people as mentioned earlier. However, they could also result from some sexually transmitted diseases, genital cancers, or infections of the lower extremity (legs) on the same side.
What are the complications of swollen lymph nodes?
There may be some complications associated with enlarged lymph nodes. If the lymph node swelling is related to an infection that is not treated, then an abscess (a pus-containing cavity) may ensue, which may require incisional drainage and antibiotics. The skin underlying the enlarged lymph node may also become infected.
In other cases, the lymph node may become very large and compress other nearby structures in the body. This could be a serious and debilitating problem that may require immediate medical or surgical attention. For example, the lymph node in the underarm (axilla) can compress the blood vessels and nerves supplying the arm. An enlarged lymph node inside the abdomen may compress the intestines and cause an obstruction of the intestines.
