They are round and small tissue masses on your body which is integral part of lymphatic system. Lymph nodes play a vital role in defense mechanism for fighting against infection. The lymph nodes produce lymphocytes which filter the harmful bacteria and other infection causing microorganisms to travel into the bloodstream. They also help in retaining the fluid balance. Swollen lymph nodes get swollen mostly under the jaw, behind ears, armpits and groin area.
When you are keeping good health you will not feel lymph nodes. But when they become swollen it can grow 2-3 times larger so that you can feel them distinctly.
There can be pain or tenderness under the arm. Redness and warm feeling indicates swollen lymph nodes. For some people there can be other symptoms like fever and sore throat due to swollen lymph nodes. These symptoms are indicative of infection which has caused inflammation of lymph nodes.
When the number of bacteria or virus exceeds in quantity then lymphocytes become incapable of filtering them. This will eventually cause accumulation of bacteria on the lymph nodes making it swollen.
It can occur due to infectious bacteria that causes strep throat, tooth infection, skin infection or ear infection. Sometimes lymph nodes can get swollen due to sexually transmitted diseases which is also an infectious one. Infection on the breast, several types of cancer and chronic immunity disorders like lupus and arthritis can also cause inflammation of the lymph nodes.
Your doctor will physically examine the area and look for other symptoms like redness and tenderness under the arms for detecting the size of lymph nodes.
Read more on Lymph Node Locations
For milder form of infection no treatment is required. You will get back to normalcy in a couple of days. If the armpit is very painful due to inflammation and infection you need to consult your doctor.
Oral antibiotics are prescribed for destroying bacteria causing infection. You will be given ibuprofen and other painkillers for reducing inflammation. Tylenol and aspirin can also be taken. However if the underlying cause is autoimmune disorder like rheumatoid arthritis then treatment is given accordingly for controlling the symptoms.
Home Remedies :
You can try using a warm compression on the swollen lymph nodes under arm. Over the counter painkillers are useful in controlling the inflammation and pain.