Many people experience armpit pain at some point in their life. Minor infections and overexertion are regularly at the root of the pain. However, armpit pain may be a sign of other, more serious health conditions.

Less commonly, armpit pain can indicate swollen lymph nodes or the presence of breast cancer.

In this article, we cover the common causes of armpit pain, when to see a doctor, and how to treat the pain when it occurs.

Causes

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Many different factors can lead to armpit pain.
Many factors either contribute to or cause armpit pain, including some skin issues, infections, and immune conditions.

Depending on the cause and severity, symptoms may vary from mild irritation to severe discomfort and distress.

A range of treatments is available to soothe discomfort in most cases, although a person will often need to treat the root cause for more permanent relief.

Common causes of armpit pain include:

Swollen lymph nodes

The lymph nodes are crucial for the successful action of the immune system. They gather foreign bodies and stimulate the release of immune cells, which destroy and remove these invading bodies.

During infections, the lymph nodes fill with harmful cells and begin to swell. This enlargement causes inflammation and pain.

Causes of swollen lymph nodes include:

the common cold
upper respiratory infections
viral infection
strep throat
ear infections
measles
mononucleosis
tooth infections
wounds and skin infections
Allergens and skin irritants

Many deodorants, antiperspirants, body washes, soaps, and laundry detergents contain skin irritants and allergens.

Some of these may lead to allergic contact dermatitis, a condition that causes redness and tiny blisters.

Similarly, irritant contact dermatitis can result in redness, pain, swelling, and heat.

Pets and environmental factors, such as potentially inflammatory substances in a workplace, also carry known allergens that trigger an immune response in the armpit.

Psoriasis

Psoriasis is an autoimmune condition that has effects on the skin in various parts of the body, including the armpit area.

It can lead to different types of plaque or scale developing on the skin, as well as itching, discomfort, and pain.

The symptoms of psoriasis can be highly uncomfortable and painful, especially if friction and moisture occur. Given its location on the body, both of these factors can affect the armpit.

For more information on psoriasis, click here.

Bacterial and fungal infections

Ringworm, or tinea corporis, is a common fungal infection affecting the uppermost layer of skin. It triggers a red, ring shaped rash.

As fungi thrive in warm, moist environments, the armpit is a target location for the infections that the fungi can cause.

Ringworm fungi also use the keratin present in hair as food. Ringworm rashes can be painful and lead to inflamed, itchy, and scaling skin.

Bacteria also flourish in moisture and warmth, so bacterial infections can also develop quickly and contribute to inflammation and pain in the area.

Intertrigo

Friction and moisture in the folds of the skin can lead to a type of inflammation called intertrigo. Intertrigo results in redness, pain, and burning, and it may also cause an unpleasant odor.

Without treatment, secondary bacteria or fungal infections may also develop, causing further pain.

Candida is a type of yeast that can cause intertrigo. It turns the skin red and causes the development of white plaque.

Sore muscles

There are several armpit muscles with underlying connective tissues, arteries, veins, and bones.

Strained pectoral, or chest, muscles — which people use for lifting and pulling — can often cause underarm pain.

Any damage to the coracobrachialis muscle, or upper arm muscle — which assists people in throwing and pushing motions — may also cause armpit pain.

Cancer

The lymph nodes in the chest, including those in the armpits, often work extremely hard when cancer develops in the upper body.

In particular, painful lymph nodes may accompany breast, lymph, and respiratory cancers.

Some people may also experience painful lymph nodes as a side effect of cancer treatments, such as radiation therapy, chemotherapy, and surgery.

Cancers that commonly cause armpit pain include:

lymphoma, or cancer of the lymphatic system
leukemia, or cancer of the blood forming tissues, including the lymphatic system and bone marrow
cancers that have spread from another part of the body, including breast cancer, which develops nearby
Heartburn

Heartburn, in which stomach acids travel back up the esophagus — or the pipe down which food travels — can cause shooting, sharp chest pain and, less commonly, pain in the armpit.

Cysts

These develop when body fluids build up in the armpits, causing swelling and pain.

Cysts can become infected, especially by Staphylococcus bacteria, which usually live on the skin.

Lipomas

A lipoma is a lump of fatty tissue that feels rubbery. A person can move it around under the skin. Most lipomas are noncancerous and do not cause pain.

However, lipomas that grow rapidly can cause pain by putting pressure on the nerves or blood vessels. People should seek medical attention if these develop.

Boils or ingrown hairs

When inflammation occurs in a single hair follicle, a boil or furuncle may develop. Boils are red, swollen lumps that are tender to the touch.

When neighboring hair follicles become infected, the underlying tissue may feel inflamed and painful.

Diabetes

Diabetes can give rise to neuropathy, or nerve damage, causing burning pain in the affected body part.

Diabetic neuropathy may develop in people with long term presentations of the condition who do not receive treatment.

Learn more about diabetes here.

Some autoimmune conditions

Lupus is a long term autoimmune condition causes inflammation throughout the body, including in the lymph nodes.

Rheumatoid arthritis is another example. This condition can lead to swelling and inflammation of the inner tissues of the joints, which may affect the armpit.

Hidradenitis suppurativa

This is a chronic condition that causes inflammation of the sweat glands beneath the hair follicles.

Symptoms usually begin as pimple-like bumps or blisters that turn into cysts and boils. Eventually, these wounds may break, weep, and form tunnels under the skin.

Early medical attention and treatment can help a person prevent scarring and potential infection.

Shingles

Shingles causes a painful and scaly rash that often affects the chest, back, and armpits. The herpes zoster virus is what causes shingles.

Find out more about shingles here.

Peripheral artery disease

Peripheral artery disease narrows the small blood vessels of the arms and legs, reducing oxygen flow to the surrounding tissues.

Oxygen deprived muscles and cells begin to wither and die, which can cause intense pain.


When to see a doctor

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A person should seek medical attention if a fever accompanies armpit pain.
People should seek medical attention if armpit pain becomes severe or interferes with daily life.

Minor health complications such as the common cold, muscle soreness, and bacterial infections are the most common reasons for pain in this area.

However, when armpit pain occurs with lumps and soreness in the area, it may indicate serious infections or an immune condition.

Though rare, serious health complications that could be causing armpit pain include:

cancer
tuberculosis
some sexually transmitted infections, especially syphilis
cat scratch fever, which might occur due to a bacterial infection from a cat scratch or bite
HIV, which can cause a range of dangerous infections due to reduced immune activity
Symptoms that suggest a need for urgent medical attention include:

swelling in the lymph nodes that lasts for more than 1–2 weeks without a known cause
extremely sore armpits or lymph nodes that are tender to the touch
swellings on multiple lymph nodes across the body, such as in the groin, head, and neck
fever and night sweats
hard lumps in the armpit region or lymph nodes
swallowing and breathing difficulties
unexplained weight loss
constipation or altered bowel movements
unexplained, continuous exhaustion
In some people, especially those who have weaker immune systems, lymph nodes may develop an infection and require medical intervention.

Without treatment, the moderate-to-severe health risks include:

Abscess: When a lymph node overworks, invading cells, immune cells, and dead tissues can build up. This allows bacteria to form a pocket of pus. Abscesses can be extremely painful and may require treatment with antibiotics and drainage.
Bacteremia, or an infection of the bloodstream: Untreated bacterial infections, especially those of the lymph nodes, can move into the bloodstream, causing sepsis. Sepsis can be life threatening and needs immediate medical attention. Without proper treatment, sepsis can lead to organ failure and may be fatal.
People who notice any of these symptoms alongside armpit pain should seek medical attention immediately.