Swollen Lymph Nodes: Causes & When To Worry

Lymph nodes are small, bean-like, glands that have a very important role in immunity, since they filter the lymph, removing virus and bacteria that can be cause an infection. Once removed, these micro-organisms are destroyed by lymphocytes, which are immune cells present inside the lymph nodes.  

Lymph nodes can be found throughout the body, but are more commonly found in groups, in places such as the the neck, underarms and groin area. Each group is responsible for helping to fight infections that develop nearby, getting inflamed, or swollen, when that happens. That's why swollen lymph nodes can appear due to simpler problems, such as a skin infection or UTI, or more serious conditions, such as cancer.

Swollen Lymph Nodes: Causes & When To Worry

What can cause swollen lymph nodes 

Lymph nodes swell up when there is a nearby trauma or infection, so the location where they get swollen can help with the diagnosis. About 80% of swollen lymph nodes in people under 30 years old, are due to local infections, but they can also have other causes:

1. In the neck 

The lymph nodes in the neck can swell on the lateral area, but also under the jaw or near the ears. When that happens you may feel, or even see, a small lump in those areas, which can be a sign of:

  • Tooth abscess;
  • Thyroid cyst,
  • Changes in the salivary glands;
  • Inflamed throat;
  • Pharyngitis or laryngitis;
  • Cut or bite mark in the mouth;
  • Mumps;
  • Ear or eye infection.

In more rare situations, swollen lymph nodes in the neck may also signal a tumor in the region, such as the throat, larynx or thyroid.

2. In the groin

Groin lymph nodes may also get swollen due to infection or trauma to the legs, feet or genital area. One of the most common causes are urinary tract infections, but it can also happen after a genital surgical procedure or due to some type of sexually transmitted infection. In rarer cases, swollen lymph nodes in the groin can also be a sign of cancer in the genital area, such as vulvar cancer, vaginal cancer or penile cancer.

3. In the armpit

The most common causes of swollen axillary lymph nodes are wounds or infections in the hands, arms, or axilla, due to a cut, ingrown hair or furunculosis. However, this type of swollen lymph nodes can also signal a more serious problem, such as lymphoma, especially if there is nocturnal fever and transpiration. But there are other situations such as animal bites, brucellosis, sporotrichosis and breast cancer that can also cause swollen axillary lymph nodes.

Cancer is relatively rare, and often the presence of a swelling in the armpit area is not due to swollen lymph nodes, but rather a cyst or a lipoma, which are easy to treat. So if you have swollen lymph nodes that do not improve, please visit your GP.

4. In the clavicle 

Lumps in the upper part of the clavicle may indicate infections, lymphoma, lung, breast, neck or stomach cancer. If the gland in the left supraclavicular area is hard this may indicate gastrointestinal neoplasia, and it is known as Virchow nodule.

5. Throughout the body

Even though it is more common for lymph nodes to swell up in one specific area, they can also happen all over the body. This is usually related to diseases, such as:

  • Autoimmune diseases, 
  • Lymphoma;
  • Leukemia;
  • Cytomegalovirus;
  • Mononucleosis;
  • Secondary syphilis;
  • Sarcoidosis;
  • Systemic lupus erythematosus;
  • Hyperthyroidism;
  • Side-effects of medication such as Hydantoin, antithyroid agents and isoniazid. 

6. In the back of the head

Little lumps on the back of the head may indicate the scalp infections, rubeola or even insect bites. Even though it is rare, this type of lump may also happen due to cancer. 

7. Near the ears

Swollen lymph nodes near the ears may indicate conditions such as rubella, eyelid infections or conjunctivitis. 

When can swollen lymph nodes be cancer 

Swollen lymph nodes are almost always a sign of an infection. However, there are some cases in which the swelling may happen due cancer. The only way to be sure is by going to a GP and doing some blood tests, a biopsy and a tomography.

Examination of the swollen lymph nodes can help to identity the underlying cause, so the doctor will often feel the area and see if the gland moves, what's it's size is and if it hurts. Painful glands have fewer chances of being cancer.

The risk of a swollen lymph node being cancer is greater when it lasts more than 6 weeks and other symptoms occur, such as:

  • Various swollen lymph nodes throughout the body;
  • Hardened consistency;
  • Absence of pain when touching the lumps  
  • Burning sensation.

In addition, age is also an important factor because people over 50 have a higher probability of having a tumor. In case of doubt, the doctor may request a needle aspiration biopsy of the lymph node, to check if there are cancerogenous cells present.

Some neoplastic diseases that also cause swollen glands are: lymphoma, leukemia, and breast, lung, kidney, prostate, skin, head and neck, gastrointestinal tract metastasis and germinative cell tumours. 

When to visit the doctor 

Most cases of swollen lymph nodes do not require treatment, and so they disappear in less than one week. It is recommended, however, that visit GP if:

  • Lymph nodes remain swollen for over three weeks;
  • There is no pain when touching the swollen lymph node;
  • The lump increases in size with time;
  • There is weight loss with no apparent cause;
  • Other symptoms appear such as fever, fatigue, weight loss and night sweats appear;
  • Swollen lymph nodes appear in other areas of the body.

In these cases, the doctor may prescribe several tests, especially blood tests to try to identify the cause, according to the affected lymph nodes, and then start the most adequate treatment.

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