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When it comes to armpits, most of us agree there are no good sensations. A good armpit day is one where we can simply apply deodorant in the morning and ignore them until the following day, provided they remain dry and safe from tickling fingers.

But if you’re experiencing pain in one or both armpits, you’ll want to get it sorted ASAP so you can push these nether regions into the back of your mind where they belong.

There are many possible causes of unexplained armpit pain, ranging in severity from simple muscle strain to, in rare cases, breast cancer.

Read on to find out about some of the issues that could be causing your armpit pain.

Left armpit only

If the armpit pain is on your left side only, it could be a sign of angina, which is a potentially serious blood flow issue that can lead to heart attack (more information below).

However, as the left armpit is susceptible to all the same sources of pain as the right one, it could still be related to any of the other issues mentioned below. So don’t jump to any conclusions just yet.


Angina is a term for chest pain caused by poor blood flow to part of the heart, depriving the muscle of oxygen. It can come on during exercise or other physical exertion and subside with rest, but it can also strike seemingly out of nowhere while you’re at rest.

Although the pain normally originates in the chest around your heart, it can spread to your arms, back, shoulders, neck, jaw, and armpits.

Pain in the left armpit in particular is associated with angina. Other symptoms may include fatigue, pain that mimics indigestion, and shortness of breath.

Angina has various risk factors, which include age, genetics, lifestyle choices like smoking, drinking, poor nutrition, lack of exercise, and even habitual exposure to dust pollution.

If pain only strikes during episodes of physical or mental stress and subsides with rest or medicine, it may be what’s known as stable angina. This can be manageable with a combination of lifestyle changes and medications such as aspirin or statins.

If pain occurs even at rest and doesn’t improve with medication, it may be unstable angina. This is a medical emergency and requires immediate hospitalization to stave off a heart attack.

In either case, the best thing you can do if you suspect you may have angina is to see a doctor right away.


Peripheral artery disease is caused by the narrowing of arteries in the extremities due to a buildup of plaque comprised largely of fats, cholesterol, and calcium. It’s most commonly felt in the legs, but can also occur in the arms, potentially causing pain in the armpits.

For some time, there may be no symptoms associated with PAD. But when symptoms appear in the legs or arms, they may include aching or burning pain, cooler-than-normal skin, and frequent infections. The pain tends to feel like cramping.

Risk factors are much the same as those of angina, including genetic predisposition, advanced age, smoking, poor diet, obesity, and high cholesterol. As is the case with so many health conditions, the most important thing you can do to reduce your risk is to avoid smoking.

Also similar to angina, the condition can be improved with lifestyle choices such as healthy eating and exercise. Medications that a doctor might prescribe in addition include aspirin or drugs to reduce blood pressure or cholesterol.

Breast cancer

Most armpit pain has a more benign cause, but it is a possible symptom of breast cancer that has spread beyond the breast.

Breast cancer can be painless for a time, but in some cases it can cause pain in the chest area. And while breast cancer normally affects women, it is possible for men to get it too, though more rare.

Other warning signs include a lump in the breast, a change in the appearance of a breast or nipple, and nipple discharge.

Genetics are believed to be a factor in only about 10 percent of cases. Other risk factors include older age, smoking, alcohol use, having overweight or being physically inactive, hormone use, dense breasts, history of radiation to the chest, and not having children.

As with any cancer, early detection improves chances of recovery.

Going in for screening as recommended by your doctor is the most effective way to detect breast cancer early — a mammogram can find cancer in the breast much earlier than it’s possible to feel via a self-exam; up to 2 years earlier.

The American Cancer Society recommends annual mammograms for those 45 and older with an average risk of breast cancer.

But if you and your doctor suspect your armpit pain may be related to breast cancer, getting a mammogram or other screening may be an important next step.


Remember when your parents set you up on a playdate with the neighbor kid with chickenpox so you’d contract it on their schedule instead of getting it right before the family camping trip?

Well that virus (called the “varicella-zoster” virus) is still dormant in your body, chillaxing in nerve tissue near your brain.

At any moment it can wake up and cause a shingles outbreak, which can involve severely painful rashes wrapping around the torso on one side or another, potentially via the armpit. But was it a good camping trip, at least?

There’s no cure for shingles, but its symptoms can be treated with prescription antiviral medications such as acyclovir and valacyclovir, as well as by prescription and nonprescription topical anesthetics, corticosteroids, or capsaicin.

A shingles episode generally lasts just 2 to 6 weeks, and most people only experience one outbreak in their lifetime. So no hard feelings, mom and dad.

Swollen lymph nodes

Fun fact: Your body produces around two liters of lymph per day.

This colorless fluid transports white blood cells around the body on patrol for infections to fight. Your body also has a series of glands called lymph nodes that filter this fluid, catching and detaining pathogens and contaminants to protect the rest of the body.

Lymph nodes, as fans of morbid Black Death history are aware, are famously located in the groin, neck, and — the protagonists of this article — the armpits. But there are actually about 600 of them distributed throughout the body.

Lymph nodes are normally the size of a pea, but if they’re actively fighting an infection they can swell and become painful. This is normally not a cause for concern — it’s a sign that your immune system is functioning properly, flooding the site of infection with lymph fluid.

Swelling should resolve as you recover from the infection. If swelling in your lymph nodes hasn’t improved within 2 weeks though, you may want to see a doctor to make sure everything’s okay.

Contact dermatitis

Contact with certain materials and chemicals can cause a reaction on the skin known as contact dermatitis, which can irritate the skin, making it red, itchy, dry, flaky, or swollen.

Contact dermatitis can take the form of allergic contact dermatitis if the skin reaction is an allergic response, or irritant contact dermatitis if the skin is simply irritated by direct contact with a substance.

Armpits are vulnerable to both forms of contact dermatitis, as we’re always covering them up with clothes or slathering on deodorants and antiperspirants.

Common sources of allergens applied to the armpits include fragrance compounds and essential oils such as those found in deodorant. In fact, deodorants are among the cosmetic products most likely to cause an allergic skin reaction.

Other potential irritants that may come in contact with the armpits include:

  • antibacterial ointments
  • isothiazolinones (bacteria-fighting substances found in some body washes and personal care products)
  • formaldehyde (sometimes found in clothes marketed as “permanent press” or “wrinkle resistant”)
  • cocamidopropyl betaine (another chemical sometimes found in personal care products and cosmetics)

Luckily contact dermatitis isn’t usually severe, but it can turn into a vicious cycle; it causes itchiness, and itching can further damage the skin barrier, making the symptoms worse.

Usually the best way to prevent contact dermatitis is to determine the offending substances and avoid touching them.

Other skin conditions (cysts, boils, ingrown hairs, lipomas, hidradenitis suppurativa)

Your armpit pain could be related to numerous other skin conditions, even if the pain feels deeper — nerves can be weird like that. Let us count (some of) the ways:


These fun fellas come in two types: epidermoid and sebaceous.

Epidermoid cysts are caused by skin cells that continue to multiply while trapped deeper in the epidermis than they should be.

Sebaceous cysts happen when glands which secrete sebum (an oily bodily fluid) become clogged and a small reservoir of sebum develops under the skin. Cysts can’t really be prevented, but luckily they usually go away on their own.


Boils (aka furuncles) are pimples’ bigger, uglier cousin. Appearance-wise, they have a lot in common with cysts. But unlike cysts, boils are caused by a bacterial or fungal infection, so they can be spread on contact.

The infection causes pus to collect under the skin’s surface, swelling into a large, painful bump on the skin. Boils should be treated by a doctor, as they have methods for cutting and draining them without allowing them to spread.

If you attempt to drain a boil by squeezing it, it may spread and form a cluster of boils — known as the dreaded carbuncle.

Ingrown hairs

When you shave your armpits, you may inadvertently cause a stray hair to change direction and grow into the skin, eventually becoming infected, inflamed, and painful.

This can happen anywhere hair is removed from the body, but it’s thought that curved hair is most susceptible to becoming ingrown. Ingrown hairs will generally resolve within 1 to 6 months, during which it’s recommended that you stop shaving the area.


A lipoma occurs when fatty tissue collects under the skin to form a soft bulge, normally under two inches in length. Most lipomas aren’t painful, but they can be if they’re pressing against nerves or if they contain a lot of small blood vessels.

Although they may look alarming to the hypochondriacs among us, lipomas are normally harmless. Why they form is a bit of a mystery, but they can be removed by a doctor if you have a concern about appearances.

However, the downside of lipomas being totally harmless is that some health insurance plans won’t cover their removal.

Hidradenitis suppurativa

Also known as acne inversa, hidradenitis suppurativa is a chronic condition resulting from clogged sweat glands becoming enlarged and extra susceptible to infection. The area around the glands fills with pus, causing large, red, painful bumps to form and eventually burst.

The condition’s exact cause isn’t known, but it may be related to genetics, hormones, and environmental conditions. Fortunately it’s not contagious. While there is no cure, a doctor can help treat existing flare ups and prevent new ones.

Muscle strain

If you’ve been tearing it up at the gym lately, your pain could be caused by muscle strain.

This could also involve an injury to a tendon such as the pectoralis major tendon. Muscle strains are caused by overuse or incorrect use of a muscle, such as by rotating a limb under pressure in an unnatural way.

Since muscle strains are often painfully obvious as they happen, try to remember whether you’ve experienced any sudden pain during a recent workout. If so, think RICE:

  • Rest: Avoid putting undue stress on your injury.
  • Ice: Ice the injury for 20 minutes once every 2 to 3 hours for 3 days following the injury.
  • Compression: Wrap the injury with an elastic bandage (but not too tight!). If it’s a rib injury, don’t wrap.
  • Elevation: Sleep in a sitting-up position to keep the injury above your heart — this can help with swelling.

Depending on the severity of the strain and the duration of the injury, it may help to see your doctor or a physical therapy specialist.

If your armpit pain doesn’t seem to be improving on its own, or if you notice swelling, a rash, or a lump in your armpit, you should see a doctor to be on the safe side.

If the pain is related to a temporary skin condition such as a boil, cyst, or ingrown hair you’ll want to get it checked out if:

  • it’s especially painful
  • it gets worse or doesn’t show signs of improvement after a week of self-treatment
  • it’s accompanied by other symptoms such as fever
  • it’s a recurring problem
  • you have a compromised immune system

If you suspect contact dermatitis is the cause, a dermatologist can help you figure out what the potential allergen or irritant is in order to help you avoid it in the future.

If your armpit pain sounds like it could be related to angina, peripheral artery disease, or cancer, a doctor’s visit should be #1 on your to-do list. These are serious conditions, and it’s always best to catch them as early as possible.

Complications / risks

Skin infections such as boils and cysts are usually thought of as unfortunate but not a serious threat to health. However, although rare, it’s possible for the infection to pass into your bloodstream and become life-threatening.

Blood poisoning, or sepsis, can cause infections throughout your body, including in the heart and bones.

If you visit the doctor, come to the appointment ready to explain when the pain started and what other symptoms are troubling you. They’ll of course want to take a good, hard look at your armpit, and they may examine other parts of your body for more clues.

They may collect samples for diagnostic tests such as blood samples or tissue biopsies if a lymph node condition or cancer is a possibility. The blood test may include a complete blood count (CBC), which is a common test that helps diagnose a wide array of conditions. The doctor may also order more specific blood tests.

The treatment for what ails your armpit will ultimately depend on the cause, but here are some general tips:

  • For muscle strain, rest is key. Applying ice for 20 minutes every 2 to 3 hours can help in the first 3 days after injury. Sleep in a reclined but upright position, keeping the armpit at a level above the heart.
  • For a boil, cyst, or ingrown hair, resist the urge to pick or squeeze! Wash and dry the area gently twice per day. Apply a warm, damp cloth to the infection for up to 30 minutes, 3 or 4 times per day; doing so can help with drainage.
  • To prevent ingrown hairs, wash the area before shaving, lubricate skin with a shaving cream or gel, use a sharp, single-bladed razor, and dry the area thoroughly after shaving.
  • For skin irritations such as contact dermatitis and shingles, there are several options to help you ignore the nagging symptoms. Apply a calamine lotion or hydrocortisone cream, or take a colloidal oatmeal bath.

Just as treatments depend on the underlying cause, so do prevention strategies.

  • Get an annual physical to stay on top of any health changes as they crop up.
  • The American Cancer Society recommends that all women aged at least 45 should get an annual mammogram. It also counsels women at high risk for (or those with a family history of) breast cancer to get an annual MRI and mammogram beginning at age 30, depending on the individual and her doctor’s advice.
  • There’s a shingles vaccine available, and the CDC recommends that those 60 or over should get it — this applies whether or not you recall having chickenpox.
  • Practice good hygiene. And don’t introduce multiple personal care products at once — this can help you quickly realize if a new product is causing an adverse skin reaction.