Lymph nodes are small and bean – shaped glands throughout our bodies. Lymph nodes are part of the lymph system, which cares waste materials, nutrients and fluid (lymph fluid) between the body tissues and bloodstream. The lymph nodes are important parts of our immune system which is our body’s defense system against diseases. The lymph nodes filter lymph fluid as it flows through them, trapping viruses, bacteria and other foreign substances, which are then destroyed by lymphocytes (white blood cells). Lymph nodes can be found in groups or singly. They can be large as an olive or small as the head of a pin. Group of lymph nodes can be felt in the underarms, groin and neck. Lymph nodes generally are not painful or tender. We know that most lymph nodes in our bodies cannot be felt.
Symptoms of swollen lymph nodes
We know that our lymphatic system is a network of lymph nodes, vessels and organs that are situated throughout the body. It is known fact that many lymph nodes are located in the neck region and head. Lymph nodes which frequently swell are in this area, as well as in your groin area and your armpits. Swollen lymph nodes are a sign that something is wrong somewhere in your body. When your lymph nodes first swell, then you might notice:
- Swelling that may be the size of a pea or kidney bean, or even larger in the lymph nodes
- Tenderness and pain in the lymph nodes
Depending on the cause of the swollen lymph nodes, other signs and symptoms can include:
- Night sweats
- Hard, fixed, rapidly growing nodes, indicating a possible tumor
- General swelling of the lymph nodes throughout your body – which may indicate an infection, such as mononucleosis or HIV, or an immune disorder such as rheumatoid arthritis or lupus
Causes for swollen lymph nodes
Lymph nodes are located in group and each group drains a specific area of the body. You may be more likely to notice swelling in some areas, such as in your groin, in your armpits, under your chin and in your neck. The site of the swollen lymph nodes can help to identify the underlying cause for it. An infection, particularly a viral infection, such as the common cold is the most common cause for swollen lymph nodes. Also there are other possible causes for swollen lymph nodes:
- Common infections: 
- HIV (human immunodeficiency virus) – the virus that causes AIDS
- Skin or wound infections, such as cellulitis
- Infected (abscessed) tooth
- Ear infections
- Strep throat
- Uncommon infections:
- Cat scratch fever – a bacterial infection from a cat scratch or bite
- Toxoplasmosis – a parasitic infection resulting from contact with the feces of an infected cat or eating undercooked meat
- Certain sexually transmitted infections, such as syphilis
- Immune system disorders:
- Rheumatoid arthritis – a chronic inflammatory disease that targets the tissue that lines your joints (synovium) 
- Lupus – a chronic inflammatory disease that can target your joints, skin, kidneys, blood cells, heart and lungs 
- Leukemia – cancer of your body’s blood – forming tissue, including your bone marrow and lymphatic system 
- Lymphoma – cancer that originates in your lymphatic system
- Other cancers that have spread (metastasized) to lymph nodes
Also there are other possible but rare causes include certain medications, such as preventive medications for malaria and anti – seizure medication phenytoin (Dilantin).
Complications of swollen lymph nodes: If the infection is cause for your swollen lymph nodes and if they are not treated, then complications can happen such as
- Bloodstream infection (bacteremia): This is a bacterial infection in your body which can progress to sepsis. Sepsis is an overwhelming infection of your bloodstream. This condition can progress to organ failure and death. Hospitalization and intravenous antibiotics are treatments for this condition. 
- Abscess formation: An abscess is a localized collection of pus which is caused by an infection. Pus has bacteria, dead tissue, white blood cells, fluid or other invaders. A pus may need antibiotic treatment and drainage. 
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