What Causes Armpit Pain?

Armpit pain has many causes. Some, like muscle strain and rashes, are mostly a nuisance. Others, like nerve compression and infections, are more serious conditions. Pain may be the only symptom, but it is possible to also have a rash or swollen lymph nodes in or around the armpit.

This article looks at what makes up the armpit (axilla), the many possible causes of armpit pain, how it's diagnosed, and your options for treatment and prevention.

Causes of Armpit Pain

The armpit is made up of structures like nerves, skin, sweat glands, blood vessels, lymph nodes, muscles, and bones. Armpit pain can be caused by anything that affects one or more of these.

In addition, conditions involving structures outside the armpit can cause referred pain, or that which comes from a different area than where it's actually felt.

Some things may cause pain in only one armpit. Others can make both sides hurt.

Muscle Strain

Any of the muscles in and around the axilla can become painful from overuse and muscle strain. Activities that can cause this type of pain include:

• Lifting
• Pulling
• Throwing
• Pushing

Pressure on the muscles and other armpit structures (e.g., from using crutches) can also cause pain.

Injuries

Armpit pain is often the result of an injury. Structures in the armpit can be injured in several ways.

The network of nerves forming the brachial plexus is a vulnerable spot. It can be injured when an arm is forcefully pulled or flexed. Armpit pain may be caused by:

• Loss of motion in the shoulder
• Weakness
• Numbness or tingling in the hand or arm

Other injuries in this region, including shoulder dislocations, can cause axilla pain.

Skin Irritation

Irritated skin in the armpit can lead to pain. This can be caused by:

• Clothing that's tight under the arms
• Rough fabrics
• Shaving

Personal care products can cause either irritant contact dermatitis or allergic contact dermatitis, reactions to things that touch the skin.

Products that can cause irritation include:

• Deodorants
• Soaps and body washes
• Lotions
• Shaving cream
• Laundry detergents or fabric softeners

Rashes

The armpit is a prime rash site because of the skin folds and a tendency to be warm and wet. Rashes that can affect the armpit include:

• Acanthosis nigricans: A velvety rash with darkened skin. It's often found in skin folds and is more common in people with diabetes or obesity.
• Psoriasis: A scaly rash caused by a build-up of dead skin cells. The skin is red or dark with silvery scales. As a chronic condition, the rash reappears.
• Hidradenitis suppurativa: A chronic condition involving sweat glands. The rash is similar to severe acne.
  

Armpit Infections

The armpit's skin folds and warmth make it a good breeding ground for infection. Many of these are fungal or bacterial.

Both local and systemic (bodywide) infections can lead to armpit pain. Some of these cause inflammation in the axilla. Others affect the lymph nodes in the armpit.

Fungal Infections

Fungal infections common to the armpit include:

• Intertrigo: A type of yeast infection (candidiasis), intertrigo usually causes a very red, shiny rash with scaling in areas where skin touches skin.
• Ringworm (tinea corporis): This may occur anywhere on the body. It often causes an itchy rash in circles that get bigger as it grows.

Bacterial Infections

Several common bacterial skin infections may lead to pain in the armpit. They're often associated with redness or swelling.

Erythrasma is a common one. It begins as a pink rash that turns brown and scaly. While often mistaken for a fungal infection, erythrasma is caused by the Corynebacterium minutissimum bacteria.

Other infections include:

• Cellulitis: This deep infection causes red, swollen skin. It may cause fever and red streaks moving away from the site. Cellulitis can be a medical emergency.
• Folliculitis: An infection in the hair follicles causes red spots to develop, possibly with a red ring around them.
• Furuncles (boils): These red bumps filled with pus may quickly get bigger.
• Carbuncles: This cluster of boils may also cause fever and fatigue. Untreated boils may develop into an abscess.

Systemic Infections

Body-wide viral infections can cause pain and swelling in the lymph nodes. These can be:

• Viral: Mononucleosis (mono) and HIV/AIDS
• Bacterial: Cat scratch disease, syphilis, tuberculosis
• Parasitic: Toxoplasmosis

Infections in nearby body parts may also drain to the lymph nodes in the axilla. That can cause pain and swelling. These areas include:

• Breast (mastitis)
• Hand
• Arm
• Neck
• Parts of the chest and upper abdomen

Enlarged Axillary Lymph Nodes

Pain in the armpit may be accompanied by swollen, tender lymph nodes (lymphadenitis). The swelling may not be obvious early on. It may affect one or both sides.

Axillary (armpit) lymph nodes may swell for a number of reasons. Common reasons include infections, autoimmune disease, and cancer.

Autoimmune Disease

In autoimmune diseases, your immune system mistakes a healthy cell or tissue for something harmful, like a virus. It then launches an attack.

Autoimmune disorders like rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE or lupus) sometimes lead to enlarged, painful lymph nodes in the armpit.

Cancer

Lymphomas, such as Hodgkin's lymphoma, may begin in the axillary lymph nodes, causing them to swell. Others may spread to these lymph nodes, with some of the more common ones being:

• Breast cancer
• Lung cancer
• Melanoma (a type of skin cancer)

In some cases, lymph node pain and swelling may be the first sign of cancer.

Lymphedema

Lymphedema is often a side effect of cancer or cancer treatment. It is caused by a buildup of fluid (lymph) due to damage or removal of lymph nodes.

Lymphedema in the arm is especially common in people with breast cancer and can lead to swelling and pain in and around the armpit.

Shingles

Shingles is a painful condition caused by the chickenpox virus (varicella-zoster). This virus stays in your body forever. It usually lies dormant in the nerve roots.

Sometimes, it reactivates and causes shingles. The first symptom is pain in the area served by that nerve (called a dermatome).

When the dermatome that serves the area around the armpit is affected, you can experience armpit pain. A painful rash usually develops a few days later. It's confined to the dermatome, as well.

Nerve Compression

Nerve compression (pinched nerves) in the armpit may cause armpit pain that is often described as burning. You may also have weakness, tingling, or numbness in the hand or arm.

Nerve compression may be caused by:

• An injury
• Pressure on the nerves from a tumor or swelling
• Pancoast tumors (from a type of lung cancer): Pancoast tumors also cause swelling of the face, neck, or upper arms.
  

Other Causes

• Benign (harmless) masses: These include cysts, lipomas, and fibroadenomas.
• Acid reflux: In some cases, pain is only felt in the armpit.
• Peripheral arterial disease (PAD): Narrowing of the major blood vessels supplying the arm.
• Menstrual period-related pain: Breast tenderness just before and during your menstrual periods may radiate to or only be felt in the armpit.
• Breastfeeding: Engorged breasts are overfilled with milk; you can sometimes feel that pressure in your armpits. Mastitis, an infection in a clogged milk duct, can cause axillary lymph nodes to swell and ache.

Checking for Swollen Lymph Nodes and Armpit Lumps

To examine a lump under your armpit:

1. Lift your arm and gently place your fingers in your armpit.
2. Press on the center of the armpit and then palpate the area around it, going in front and back of the lump and along the chest wall.

Generally, a lump that is tender, soft, and moves around a little bit is less concerning than a firmer lump that is not tender and is fixed in place.

Lumps or swollen lymph nodes usually occur only on one side. If both sides are tender and swollen (along with lymph nodes in other areas of the body), this may indicate a systemic condition called lymphadenopathy.

When Should I Be Concerned About Armpit Pain?

You should see your healthcare provider for armpit pain if it:

• Is severe
• Is persistent, regardless of the severity
• Limits daily activities
• Is accompanied by other concerning symptoms, such as night sweats, a breast lump, or unintentional weight loss

Seek prompt care if you have signs of an infection, such as:

• Fever and chills
• Redness
• Drainage
  

How Armpit Pain Is Diagnosed

Your healthcare provider has several ways to figure out where armpit pain comes from.

First, they'll likely ask a lot of questions about your pain and other symptoms. They will then perform a physical exam and determine if any testing is required.

Patient Intake

They'll want to know:

• The quality of the pain: Is it sharp or dull and achy? Does it feel tingling, burning, or itchy?
• The duration: When did the pain begin? Is it constant or intermittent? Is it getting worse?
• The intensity: How severe is the pain on a scale of 1 to 10, with 1 being barely there and 10 being the worst pain you can imagine?

Other questions may include:

• What other symptoms are you having? For example, fever or chills, night sweats, pain in other locations, or swollen lymph nodes in other locations?
• Have you had a rash or redness? Have you noted any other changes in your armpit?
• Have you had any scratches or cuts on your hand or arm?
• Have you started any new activities or sports?
• Have you recently had any type of injury?
• Have you used any new deodorants, lotions, bath soaps, or laundry detergents?
• When was your last mammogram? Do you have a family history of breast cancer? Have you noted any breast lumps?
• How much is the pain interfering with your daily life?

Physical Exam

Next is a physical exam. Your healthcare provider will also look for any redness, rashes, lumps, or enlarged lymph nodes in your axilla.

They'll probably also examine the areas surrounding your armpit, including your head, neck, arms, and chest.

They may perform a neurological exam to check for nerve compression.

A breast exam can help determine if it's cancer. (Expect this regardless of your biological sex.)

Labs and Tests

The lab tests your provider orders (if any) depend on your symptoms and what they've found during a physical exam. You may be sent for a blood draw, urine test, or other types of testing.

Tests may include:

• A complete blood count (CBC) to identify if there's an infection
• Inflammatory marker and antibody tests to reveal a possible autoimmune disease
• Skin scrapings to help identify rashes
• Allergy testing to confirm allergic contact dermatitis

Imaging

For some injuries, cancer, and other masses, you may have some imaging studies done. These may include:

• Ultrasound: Uses sound waves to create a picture of organs and other structures
• Computed tomography (CT) scan: Uses a series of X-rays to produce 3D images of bones and soft tissues
• Magnetic resonance imaging (MRI): Uses a magnetic field and radio waves to create detailed images of organs and tissues
• Positron emission tomography (PET) scan: Radioactive dye is injected to show diseased cells and abnormal activity
• Mammogram: A breast scan commonly used to detect tumors

Procedures

If no diagnosis has been made by this point, or it's not a firm diagnosis, your healthcare provider may opt for other diagnostic procedures.

A biopsy is an important one for axillary pain, as it is used to diagnose or rule out cancer. S small tissue sample is collected and sent to the lab for examination under a microscope.

Treatment for Causes of Armpit Pain

The treatment of armpit pain depends on the underlying cause. In some cases, rest and over-the-counter medication may be sufficient. In others, medical intervention to address the condition causing the pain may be necessary.

As some of these conditions can progress if not treated early, it's essential that you get a proper diagnosis if your armpit pain is persistent or otherwise concerning.

How to Relieve Armpit Pain at Home

Armpit pain may be eased by a few different at-home solutions. Still, it's best to consult with your healthcare provider before using any to make sure you are on the right track and don't need anything additional.

If your pain is caused by muscle strain or other injury, you can try:

• Rest
• Icing the area
• Gentle stretching
• Over-the-counter splints (OTC), wraps, or braces if recommended
• Non-steroidal anti-inflammatory drugs (NSAIDs) such as Motrin (ibuprofen)
  

If the pain is caused by skin irritation:

• Try to avoid any products that may be responsible. (For example, change from your regular laundry detergent or soap to one that is free of dyes and fragrances.)
• Use an OTC topical ointment, such as an anti-fungal or a corticosteroid cream, if appropriate
• Use calamine lotion or oatmeal baths to soothe irritated skin

Medical Treatments for Armpit Pain

Medical treatments for armpit pain vary widely. Here are some common causes and their treatments:

• Rashes: Prescription topical and/or antibiotics
• Infections: Prescription topical and/or oral antibiotics
• Autoimmune disease: Immunosuppressants, arthritis medications (DMARDs)
• Cancer: Chemotherapy, radiation, hormone therapy
• Nerve compression: Surgery
• Shingles: Antiviral medications, prescription painkillers

Can You Prevent Armpit Pain?

Many causes of armpit pain can't be prevented, but some can. Here are some tips:

• Wear loose-fitting clothes and use hypo-allergenic or gentle products to avoid irritation.
• Warm-up properly before sports and avoid overusing your arm and shoulder to prevent injuries.
• Keep the area dry to help prevent irritation and rashes.
• Report any rashes, possible infections, and other abnormalities right away so they don't get worse.

Summary

Armpit pain has many causes. They range from simple skin irritation or muscle strain to autoimmune disorders, heart disease, and cancer.

Diagnostic tests and treatment depend on your symptoms and what your healthcare provider finds or suspects.

Some causes of armpit pain can't be prevented. However, using gentle products, soft clothing, and doing a pre-exercise warm-up may help you avoid irritation, allergies, and injuries.