What To Do if You Find an Armpit Lump

Seeing what's going on in your armpit can be hard unless you have a bothersome rash or happen to feel a lump. Finding a lump in your armpit can be worrisome. Most of the time, however, a lump in the armpit is nothing serious and will go away on its own or with treatment. In some cases, the lump could be a sign or symptom of something more serious.

If you find a lump in your armpit, here are a few possible things it could be and some ideas for how to treat it.

Ingrown Hair

Does the lump look red and inflamed or filled with pus? If so, it may be an ingrown hair or infected follicle from shaving or using antiperspirant, Roshini Rajapaksa, MD, clinical associate professor of medicine at the NYU School of Medicine and a Health medical editor, told Health.

Ingrown hairs, technically called pseudofolliculitis barbae, also referred to as razor or shaving bumps, occur after shaving when the hairs curve back and re-enter or grow under the skin. They are more likely to happen with curly hair.

The best option for healing ingrown hairs is to avoid shaving and applying products in that area, said Dr. Rajapaksa, who also recommended cleaning the area gently with soap and applying warm compresses several times a day for a few days to allow it to heal.

It is also recommended that you avoid plucking the ingrown hair, as it increases the chances of the new hair growing back into the skin. If avoiding shaving isn't an option, it is recommended that you shave daily using the following steps:

• Wash the area with a gentle cleanser.
• Apply a warm compress to the area for about five minutes.
• Apply shaving cream and allow it to sit for several minutes.
• Shave with short strokes in the direction of hair growth, avoiding shaving over the same area multiple times; also, avoid stretching the skin.
• When finished shaving, apply a cool compress to the area.
• Store your razor in a cool, dry place, and avoid using the same blade more than five times.

If you frequently experience ingrown hairs and want a more permanent solution to getting rid of them, talk to a healthcare provider about laser hair removal. This will remove the hair itself and prevent the growth of new hair.

Lipoma

If your lump isn't red, inflamed, or filled with pus, another possibility is that it's a lipoma, which is a knot of fatty tissue that commonly grows in places like the shoulders, neck, arms, armpits, upper back, buttocks, and upper thighs, said Dr. Rajapaksa.

While you can get lipomas at any age, they mostly form in adults between 40 and 60. There is no known cause of them other than possibly your genetics.

Lipomas are almost always harmless and painless. However, one may cause pain if it lies on any nerves. If it bothers you, a healthcare provider can remove it, typically by making a small incision and taking out the tissue, explained Dr. Rajapaksa.

A lipoma is typically soft and rubbery and can be moved with gentle pressure. There are several subtypes of lipomas based on the type of fat the lump is made of, its location (some are deeper in the body), and what other structures it involves—like blood vessels, organs, and other tissues. You probably won't know what type it is unless you have it removed and the lump biopsied.

Since you can't always know if it's a lipoma when you feel a lump, it's safest to talk with a healthcare provider so they can properly diagnose what it is.

Swollen Lymph Nodes

You have lymph nodes throughout your body. They can be felt in the armpit, groin, neck, behind the ears, under the jaw and chin, and on the back of the head.

Lymph nodes play an important role in the immune system, acting as filters to trap "intruders" in your body (think germs and cancer cells), said Dr. Rajapaksa.

They can become tender when you have an infection like mononucleosis and enlarged (but not necessarily painful) when you have certain types of cancer (lymphoma or leukemia). The swelling and discomfort usually go away when the infection does, although it may take weeks for the swelling to subside entirely.

Some people also have small amounts of breast tissue near the armpit, so if you notice soreness just before your period, it may be due to the same hormonal changes that cause period-related breast tenderness, noted Dr. Rajapaksa.

It's possible for swelling or lumps in the armpit to be a sign of breast cancer. If you're concerned, or the lump doesn't resolve in a couple of weeks, it's a good idea to have it checked by a healthcare provider.

Lymph nodes in your armpit can also become swollen due to the COVID-19 vaccine. According to a 2022 study, 44% of participants experienced swollen lymph nodes in their armpits after receiving the COVID-19 vaccine. Swollen lymph nodes in response to the vaccine will be on the same side that you got the vaccine. They're considered a normal reaction as your body mounts an immune response and should go away within a couple of weeks.

A Quick Review

Chances are, any lump you find in your armpit isn't too serious. The lump could be a cyst, a breast infection, or (very rarely) a sign of breast cancer, said Dr. Rajapaksa. Talk to a healthcare provider if the lump:

• Doesn't disappear in a couple of weeks
• Gets bigger
• Pain gets worse
• Feels hard
• Is an irregular shape
• Is fixed in place
• Is accompanied by fever, night sweats, or unexplained weight loss

It's better to err on the side of caution and get the lump checked out, which can also give you peace of mind.