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An armpit lump may look and feel weird, but it is usually not a cause for concern. However, that does not excuse you from seeking proper medical diagnosis and treatment.
Only when you know what is causing the lump will you be able to treat it. (1) Plus, there is always the chance that it could be cancerous, and that’s something you can’t take lightly. Fortunately, cancer cells are rarely detected in armpit lumps.
Causes of Armpit Lumps
Some of the major causes behind armpits lumps are as follows:
- Lymph nodes are small groups of immune cells that look like round beans and are located in different parts of the body including your armpits. They are part of the larger lymphatic system that generates white blood cells (lymphocytes) and other disease-fighting substances that are responsible for your immunity. When the immune system detects the presence of a foreign body such as a microbe or cancer cell, it activates the lymphatic system to launch an immune response. This essentially involves producing increased amounts of immune cells to kill the invader and protect the body. However, this hyperactive immune response causes inflammation in the lymphatic system, including the lymph nodes. As more and more white blood cells accumulate in the axillary lymph nodes under your arms, they tend to grow to more than a few centimeters and stick out from under the skin. This is why a lot of people tend to get armpit lumps when they are in the throes of infection. These kinds of lumps are most common among children but can affect anyone. (2) Moreover, chronic ailments such as cancer (Hodgkin’s lymphoma) (3) and autoimmune diseases can also elicit a similar response and cause a lump in your armpit, but this is less common. (4) The enlarged lymph nodes shrink back to their normal size as you recover from the infection/illness. (5)
- The armpits collect a lot of sweat and heat due to their confined location. This warm, humid, poorly ventilated area is ideal for microbial growth. The sweat and germs may accumulate inside the skin pores and infect your hair follicles. This infection is referred to as folliculitis and causes inflammation in the hair follicles. The infected follicles swell up and form cysts or abscesses under the skin that feel like painful lumps on the surface. (3)
- The skin in the armpits is folded and rubs against itself when you move your arms and against your clothes. This constant friction causes the thin skin in this area to cover itself with extra scar tissue, which makes it thick and leathery. In some cases, this excess tissue may concentrate in a small area to form a wart-like lump that hangs from the armpit. This skin growth is known as a skin tag, which is completely benign and quite common. (6)
- Shaving your underarms can also irritate or rupture the skin and even give rise to ingrown hair, which appears as lumps in the armpit.
- Antiperspirants can clog the pores in this area along with sweat and bacteria, eventually forming cysts under the skin.
- The lump in your armpit can be a benign fatty tumor called lipoma or a boil/pimple.
- Breast cancer or breast infection can also give rise to an armpit lump. (7)
- Certain medications and vaccinations can also cause a lump in the armpit.
Symptoms of Armpit Lumps
An underarm lump may or may not be painful and can be accompanied by the following symptoms:
- Cold or flu-like symptoms that include fever, nasal discharge, cough, weakness, headaches, sore throat, and aches and pains in different parts of the body
- Rash or bumps
- Pain, warmth, redness, and tenderness in and around the lump (a sign of infection)
- Swelling in the arm
- Burning sensation
- Unexplained bruising
- Loss of appetite
- Pus or fluid discharge
- Painful, enlarged lymph nodes in other parts of the body
Look out for the following symptoms that could indicate a more serious or life-threatening condition that warrants prompt medical treatment:
- Pain, lump, or any other abnormalities in the breast (possible sign of breast cancer or breast infection) (7)
- Hampered consciousness, lack of alertness, and confusion
- Labored breathing, wheezing, or running out of breath
- Hardened lymph node that may increase in size over time
- Fever higher than 101°F
Treatment for Armpit Lumps
The treatment for an armpit lump will depend on its underlying cause.
If it feels soft, warm, and tender with pain and redness extending to the surrounding area, it may be stemming from an infection. Such lumps may grow quickly.
In such cases, the doctor may prescribe one or more of the following:
- Oral or topical antibiotics for bacterial infections
- Antifungal ointments such as clotrimazole, econazole, terbinafine, and miconazole (8) for fungal infections
- Oral anti-inflammatory drugs to bring down the swelling
- OTC pain medicine
A hard painless armpit lump that seems connected to other hard lumps under the skin and does not grow quickly may be related to breast cancer. In such a case, the doctor will first conduct the necessary tests to confirm the diagnosis.
If the diagnosis is positive, the doctor will determine the stage and type of cancer and then prescribe treatment.
Some of the commonly used cancer treatments in such cases are:
- Surgery: Your doctor will first attempt breast-conserving surgery called lumpectomy, which involves excising only the malignant tissue from the breast, a few lymph nodes, and some normal tissue. This surgery allows most of the healthy breast tissue to remain intact. (9) If this surgery is not feasible, the next option is complete breast removal or mastectomy. (9)
- Radiation therapy: This intervention involves using high-energy radiation or particles to target and destroy cancer cells, which helps promote recovery, extend your lifespan, and prevent relapse. (10)
- Chemotherapy: This therapy involves the intravenous administration of chemical medication that aggressively kills fast-growing cancer cells to stop the disease from spreading.
Diagnosing Armpit Lumps
To diagnose the cause of your armpit lump, your doctor will first inquire about your medical history and symptoms.
This is followed by a close physical examination of the armpit, which entails checking the area for redness, rashes, lumps, or enlarged lymph nodes. The doctor may also examine the surrounding areas of your armpit, such as your head, neck, arms, and chest.
A neurological examination may be conducted to see if a nerve in the area is compressed. You may also have to undergo a thorough breast exam to rule out breast cancer (even if you are a man).
The doctor may order additional tests if a lymph node condition or breast cancer is suspected. This includes blood work such as complete blood count (CBC), biopsy, (11) and marker test relevant to the suspected illness. If the findings fail to provide a conclusive diagnosis, the doctor may conduct more tests.
At-Home Care for Armpit Lump Management
Home care depends on the cause of the lump. Check with your health care provider to determine the cause. Generally, the following measures may help you manage the discomfort associated with armpit lumps:
1. Take a post-workout shower
Take a shower soon after exercising to minimize sweat buildup in the armpits.
2. Wear breathable fabrics
Wear light breezy clothes that keep your body ventilated and prevent it from sweating too much. Tight synthetic clothes stick to the skin and cause excessive perspiration, especially in the armpits.
3. Avoid shaving your armpits
Don’t shave your armpits as it can lead to skin irritation and increase the risk of lump formation.
4. Try over-the-counter medications
You can take over-the-counter analgesics such as acetaminophen or nonsteroidal anti-inflammatory drugs such as ibuprofen to relieve the pain and swelling. (12)
5. Apply a warm compress
Apply a warm compress to your armpit. The gentle heat stimulates blood circulation under the skin and thus helps reduce the pain and swelling.
Regular use of a warm compress can even make the lump go away.
- Fill a bowl with hot water (not too hot) and soak a clean towel in it.
- Take out the towel and wring the excess liquid.
- Place the warm damp towel on the affected armpit for 10–15 minutes.
6. Use a charcoal compress
Activated charcoal has strong adsorbent and detoxifying properties. When applied to the skin, it pulls the sweat, germs, and pus from your pores for a deep cleaning effect.
A charcoal compress is good for clearing skin infections. Plus, it can help reduce the pain and swelling in the area to make your lump shrink faster. (13)
- Put activated charcoal and flaxseed powder in a bowl.
- Mix in just enough water to make a thick paste.
- Smear this paste all over a paper towel and place it on the affected area.
- Let it sit for 10–15 minutes.
- Repeat this 3–4 times a day.
When to See a Doctor
Any abnormal growth on the body should be examined by a doctor to rule out serious diseases such as cancer, and the same stands for armpit lumps.
The doctor will first diagnose the underlying cause of the lump and then prescribe the appropriate treatment accordingly.
Seek immediate medical help if you notice these warning signs:
- If the lump starts growing
- If the lump is painful
- If the lump feels hard
- If the lump persists for more than a week despite the recommended treatment
- If the lump comes back after subsiding or being surgically removed
Does Breastfeeding Cause Lumps to Form in the Armpit?
Yes, in two ways.
First, inadequate release of breast milk during breastfeeding can make it collect inside the milk duct and seep into the surrounding breast tissue. This is known as engorgement, which makes your breast feel heavy, hard, swollen, tender, and painful.
Second, the warm moist environment inside the milk duct can trigger an infection called mastitis, which causes inflammation that spreads to the surrounding breast tissue. Given that breast tissue spreads all the way to the underarm area, both these conditions can cause swelling and lumps in the armpits.
Armpit lumps need to be evaluated by a doctor to eliminate the risk of cancer and other serious ailments.
Plus, only when you know what’s causing the lump will you be able to treat it, unless it goes away on its own within a week or two and does not come back, in which case you may go without medical treatment.
By and large, it is always a good idea to get any abnormal growth on the body checked out by a doctor. It does not necessarily point to anything dangerous, but it’s better to err on the side of caution when it comes to your health.
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