Last reviewed by Dr. Raj MD on January 12th, 2022.
When you have a painful lump in your armpit it can be either a bump or some type of swelling. When you have this lump it can be annoying and very uncomfortable. At times when you barely touch it you can have extreme pain.
In extreme cases of a painful lump in armpit it can actually make it uncomfortable to wear any clothes that is going to cause any pressure on the area where the lump is located.
When you find a painful lump in armpit it is important that it be diagnosed to see if it is or is not cancerous.
Causes of Painful Lump in Armpit
There are many reasons why a person would have a painful lump in their armpit. In your armpit there are lymph nodes that act as filters that will catch any cancerous tumor cells or germs.
When this happens your lymph nodes will increase in size and can be easily felt. They can be one cause of having a painful lump in armpit. Some of the reasons that they may become swollen and painful can include:
- Breast or arm infection
- Body wide viral infections like mononucleosis, herpes, AIDS, chicken pox, or shingles
- Cancers like breast cancer or lymphomas with breast cancer being the most common cause of a painful lump in armpit.
Another cause of having a painful lump in your armpit are abscesses or cysts. These can be caused by using antiperspirants instead of deodorants or shaving. Other causes of a painful lump in armpit can include:
- Sebaceous cysts — these are the type of cysts that you get when you shave and is normally caused by improper shaving that damages the hair follicles in your armpit.
- Harmless fatty growths called lipomas, which are non-cancerous. You can usually tell it is a lipoma if it is one to three centimeters in size, it is easily moved, has a soft rubbery touch, grows slowly, and maintains about the size over the years. Most of the time they are painless but they can also cause a painful lump in arm. You should see your physician to make sure it is a lipoma.
- Cat scratch disease, which is caused by a bacteria called Bartonella Henselae that is spread by the bite of a cat.
- Using certain medications
- Certain vaccinations that cause an allergic reaction, which can be due to the ingredients of penicillin, sulpha drug, or iodine. The vaccines that are most likely to cause an allergic reaction in people are smallpox vaccine, measles and mumps vaccine, rubella vaccine, typhoid vaccine, etc.
- Allergic reactions to scented soaps or powders
- Being a skin tag
- Excess breast tissue that can appear in the later stages of pregnancy
A painful lump in armpit can also be caused by a fungal infection, such as Sporotrichosis. This skin infection is caused by the fungus Sporothrix schenckii and is found on twigs, sphagnum moss, thorns of roses, and hay. This type of fungal infection is common among gardeners.
Treatment for Painful Lump in Armpit
Because a painful lump in armpit could be a sign of breast cancer it is important that a woman see her physician right away to get a diagnosis. Make sure that if you experience any lump in the armpit, painful or not, that you see your physician.
Do not try to do a self-diagnosis yourself.
The treatment for a painful lump in armpit will depend on what the diagnosis is. If it is caused by some viral infections that cause the chicken pox or shingles it will normally go away on its own without any treatment. Other viral infections will need medical attention.
If the diagnosis shows that it was caused by normal breast tissue that just caused a cyst it will also require no treatment unless it becomes very large, infected, tender, or swollen.
It is one of the many different types of cancer such as breast cancer, Hodgkin’s lymphoma, Leukemia, or Non-Hodgkin’s lymphoma then you will be sent to a physician that deals with cancer.
This physician will make out a treatment plan to get rid of the cancer such as radiation and chemotherapy.
If the cause for a painful lump in armpit is a minor cause such as from shaving it will usually go away in two to three days. If it does not go away it could be caused by something major instead and will require a diagnosis from your physician. If it is caused by a bacterial infection you may be give a prescription for antibiotics for fourteen days.
If the painful lump in armpit is a boil you will need to make sure that you are washing the area several times during the day to keep the area free from germs.
You should also not use any deodorant in the area. When washing the area make sure that you are using plain water or non-scented antibacterial soap. Sweating can promote more bacterial growth so try to wear clean clothes that will let the area breath or make sure that you clothes are made of natural fibers. It is very important that you do not squeeze or touch the boil unnecessarily.
To help ease the painful lump in armpit you can apply warm compresses to the area. The boil should burst on its own within seven days or more. When it bursts let the pus drain out and then clean the area immediately.
You can apply a clean dry sterile bandage to the area so germs do not get into the open boil. Change the bandage daily and after a few days it will be safe to leave it uncovered.