15 Common Causes of Pain in Left Armpit

Armpit is one of the sensitive parts of the body. Numerous blood vessels and nerves run through the armpits. Besides, your armpits are close to the breasts, and you may think that you have developed breast cancer. Luckily, most pains in the left armpit are not life-threatening and do not require medical help. But there are also cases that the pain is a sign of a severe health condition.

Many causes can lead to pain in left armpit. For example, you developed a lump in that area. It can also be due to skin irritation, infection, or cancer.

Causes of Pain in Left Armpit

Top 10 Causes of Pain in Left Armpit

There are many possible reasons why a person experiences pain in left armpit. Here are some of the common causes.

1. Muscle Strain

The overuse or injury of chest or arm muscles may lead to pain in armpit. The pectoralis is a large muscle of the chest that runs up to the shoulders. This muscle can be injured by lifting weights or sports. The coracobrachialis, a muscle in the upper arm, can be damaged or strained from throwing activities or sports, such as tennis, javelin, and baseball.

If the muscles of the chest or upper arm become inflamed or sprained, you may feel pain in the left armpit or both.

Read: Causes of Pain under Left Rib Cage

2. Lymphadenitis (Lymph nodes inflammation)

Lymph nodes are the oval-shaped organs that contain immune cells. These are responsible for attacking and killing unwanted contaminants or invaders, such as viruses. Lymph nodes are found in many parts of the body, such as groin, neck, and armpits. When you are sick or infected by a virus, the lymph nodes release disease-fighting cells and compounds. They may also become painful or inflamed. Inflamed lymph nodes are called lymphadenitis.

Your doctor may advise you to take a fever-reducing painkiller and warm compress. You can also alleviate the inflammation by elevating the affected area.  Antibiotics can also help in fighting the infection that leads to inflammation. If the lymph nodes are infected, an abscess may form. Your doctor will drain the abscess to alleviate the swelling. If the lymphadenitis is due to a cancerous tumor, the treatment may include surgery, radiation, and chemotherapy.

3. Pain in Left Armpit Caused by Angina


Angina is a chest pain due to reduced blood flow to the heart muscles. The blood carries oxygen, which the heart needs to function correctly. When the heart is deprived of oxygenated blood, it also leads to a condition called ischemia. Angina is a symptom of coronary artery disease and is commonly described as pressure, tightness, heaviness or pain in the chest. Other symptoms of angina may include:

  • Shortness of breath
  • Dizziness, nausea
  • Fatigue
  • Pain in arms, shoulder, neck, jaw or back with chest pain
  • Chest pain

People who are smoking, with diabetes, high blood pressure, high blood cholesterol, lack of exercise, history of heart disease and always stress have a higher risk of developing angina. If you are experiencing pain in left armpit along with chest pain, seek medical help immediately.

4. Hidradenitis Suppurativa

Hidradenitis Suppurativa is a skin condition that comes with sore lumps. It usually develops where the skin rubs together, such as the groin, buttocks, armpits, and under the breast. The small lumps may break, smell, and create tunnels under the skin. This condition may occur when the hair follicles are inflamed or blocked. Many factors can lead to blockages, such as hormones, genetics, metabolic syndrome, irregular immune system response, excess weight, and smoking.

The signs and symptoms may include:

  • Blackheads
  • Red Bumps
  • Pea-sized lumps
  • Tunnels

Early diagnosis and treatment can control the symptoms and avert further complications, such as infection, scars, limited movement, obstructed lymph drainage, social isolation, and cancer.

Read: Different Types of Pain in Left Side, Causes and Treatment

5. Sporotrichosis

Sporotrichosis, or rose handler’s disease, is an infection caused by a fungus (Sporothrix Schenck). This fungus is related to mold or yeast. Sporotrichosis condition is commonly linked with scrapes or cuts that occur when handling vegetation (wood, moss, hay, sphagnum moss, sharp-stemmed plant, and soil). The infection is common among farmers, gardeners, and nursery workers.  When the mold spores enter the skin, it may take days or months to develop.

The first symptom of this condition is a bump or nodule on the skin. The color may range from pink to purple. It is usually tender and mild but may develop an open sore (ulcer) that drains clear liquid. Without proper treatment, the nodule and ulcer can be severe. It may also spread to the arms and legs and may last for years. In severe cases, the infection may spread to joints, bones, lungs, or brain. If you think that you or someone you know might have Sporotrichosis, seek medical attention for proper diagnosis and treatment.

6. Breast Cancer

Breast cancer forms in the cells of the breast, and may occur in both men and women. The cause of breast cancer is not apparent, but the lifestyle, environmental factors, and hormones may increase the risk of breast cancer. It often starts with cells in the milk-producing ducts or may begin in the glandular tissue, or in other tissue or cells within the breast. The signs and symptoms of breast cancer may include:

  • Breast lump
  • Change in shape, size, or appearance
  • Skin changes or scaling, flaking and peeling around the nipple
  • Suddenly inverted nipple
  • Redness or pitting the skin

To diagnose breast cancer, tests and procedures may include a breast exam, mammogram, breast ultrasound, biopsy and breast MRI. If you are experiencing any of the signs and symptoms of breast cancer, see a doctor immediately for early treatment.

7. Heartburn or Acid Reflux

Heart Attack

Another cause that can result in pain in the left armpit is heartburn. It is a burning sensation in the chest area behind the breastbone. The pain is usually worse when bending over or lying down. It occurs when the stomach acid backs up into the esophagus (a tube that transfers food from mouth to stomach). Heartburn that affects your daily tasks can be a sign of a more severe condition that requires medical attention.

The symptoms of heartburn include:

  • Pain that worsens when bending over or lying down.
  • Chest pain that occurs after eating or at night.

If you are experiencing severe chest pain accompanied by other symptoms such as pain in the armpit, arm, jaw, or shortness of breath, seek medical help immediately.

Read:10 Common Causes of Sharp Pain Under Right Breast

8. Shingles near the Armpit

Singles is a viral infection that may occur in any part of the body. It looks like a single stripe of blisters that wrap around the right or left side of the torso. If there is an eruption near the armpit, it can cause armpit pain. Shingles are caused by the same virus (varicella-zoster virus) that causes chickenpox. The signs and symptoms of shingles may include:

  • Pain, burning, numbness or tingling sensation
  • Sensitivity
  • Red rashes
  • Itchiness
  • Fluid-filled blisters that break open

A person with shingles may also experience a headache, fever, fatigue, and sensitivity to light. Seek immediate medical help if the rash or pain occurs near your eyes, if you are 70 or above, if you have weak immune system due to illnesses, or if the rash is painful and already spreading.

9. Anxiety


Anxiety is also associated with underarm pain. It results in shaking, sweating, irritation, and rapid heart rate, which may cause pain in the underarms. People with anxiety disorders often have intense, persistent and excessive worry about daily circumstances. These feelings and panic can affect your daily tasks. Other signs and symptoms of anxiety may include:

  • Trembling
  • Difficulty controlling worry
  • Hyperventilation or rapid breathing
  • Feeling tense or nervous
  • Feeling tired or weak
  • Difficulty sleeping
  • Having the urge to avoid things that trigger anxiety
  • Gastrointestinal problems

See a doctor if you think that you are worrying too much and it hinders your tasks, relationship or other activities if you feel depressed and you cannot control alcohol, drug intake or suicidal thoughts.

10. Peripheral Artery Disease

The peripheral artery disease is a common circulatory problem. The arteries in the legs or arms are narrowed that results to reduced blood flow to the limbs. This condition is usually caused by atherosclerosis, in which the plaques (fatty deposits) build up in the artery walls. The risk factors include smoking, obesity, diabetes, aging, high blood pressure, family history of PAD and high level of homocysteine (protein).

If you have this problem in one or both arms, you may feel pain in the armpit. If you are experiencing numbness, pain, change in the color of arms or legs, weakness, weaker pulse, see your doctor immediately.

Other Causes of Pain in Left Armpit

  • Glandular infection – poor armpit hygiene allows bacterial infection.
  • Breast infection – Staphylococcus aureus bacteria or mastitis can cause pain in the left armpit or both. Symptoms may include pain, discharge, redness, swelling, enlarged lymph nodes and lump.
  • Using crutches – if you are using crutches, it can lead to armpit pain.
  • Connective tissue degeneration – If tissue degeneration happens in the armpits, you might experience armpit pain.
  • Shoulder dislocation – This can cause numbness, swelling, weakness and sharp pain in armpit.

Read: Top 10 Natural Remedies to Get Rid of Armpit Rash Fast

One Response

  1. karenshoun@cox.net August 16, 2017

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