18 Reasons Why You Feel Pain in the Armpit

Have you ever felt pain in your armpit? The pain in this area can be quite uncomfortable, and it can appear in one or both armpits. Sometimes you feel it a bit lower and sometimes in the center of the armpit.

There are various causes of armpit pain, some of them less serious than others. Here are some of the most common causes of pain in the left armpit.

18 Possible Causes of Armpit Pain

1. Swollen Lymph Nodes

Lymph nodes are tiny organs which include immune cells that fight infections in the body. They are everywhere, including your armpits. When they release immune cells as a response to a viral infection, they get inflamed and become sensitive to touch.

So, to help ease the pain, apply warm compresses, or take painkillers.

2. Muscle Strain

Sometimes lifting heavy weights can cause an injury that results in armpit pain. For example, this can happen if you injure the chest or arm which can damage the pectoralis muscle. Therefore, muscle strain or inflammation can cause armpit pain.

3. Angina

Angina, or lower blood flow to the heart muscles, is a sign of coronary heart disease. Besides feeling pain in the armpit, you may also have the following symptoms – nausea, shortness of breath, and dizziness.

4. Heartburn

Heartburn occurs when the stomach acids return to the food pipe. In some cases, it can cause a burning sensation in the chest and pain in the left armpit.

5. Contact Dermatitis

There are many ways you can irritate the skin underarms. For instance, using various detergents and deodorants, as well as waxing and shaving the area. This, in turn, causes a skin rash.

Even though it’s an uncomfortable feeling, it’s nothing serious so you can manage the pain.

6. Shingles

Shingles are quite painful. It is a viral infection that causes skin blisters, headaches, fatigue, fever, and light sensitivity. So, the reason for your armpit pain might be these skin blisters.

7. Diabetes

Sometimes the cause for your underarm pain could be diabetes. That’s because this condition can damage the nerves in certain parts of the body, including armpits.

8. Inflamed Hair Follicle, or Ingrown Hairs

Infection of a single hair follicle can lead to boil or furuncle which is swollen and tender to touch. Since the infection can spread to neighboring hair follicles, soon the whole area can become inflamed and painful.

9. Glandular Infection

Poor hygiene can lead to glandular infection which can be quite painful in your armpits.

10. Peripheral Artery Disease

This disease is characterized by narrowing of the smaller arteries in legs and arms. Consequently, it disrupts the supply of oxygenated blood to tissues and muscles in the limbs. And, muscles which lack oxygen can be quite painful.

So, if you have peripheral artery disease in one or both arms, you may feel armpit pain.

11. Breast Infection

Besides armpit pain, breast infection is characterized by swelling, redness, and fluid drainage. Also, the lymph nodes might be enlarged.

12. Psoriasis

This autoimmune disease affects different skin areas, including the armpits. If the affected skin area is subjected to moisture and friction, such as your armpits, it can be extremely painful and uncomfortable.

13. Cysts

Cysts are a buildup of fluid under your arms followed by pain and swelling. Moreover, they can be infected by bacteria which live on the skin, such as Staphylococcus.

14. Lupus

Lupus can inflame the lymph nodes in your armpits, making them painful and tender to touch.

15. Fungal Infection

Fungal infection such as ringworm can cause redness and rash in the form of a ring. Since fungi live in moist and warm environments, your underarms are a target for such infections. Besides pain, ringworm can cause itchiness, inflammation, and scaly skin.

16. Cancer

Respiratory, lymph, and breast cancer makes lymph nodes to work overtime in the upper body. Furthermore, chemotherapy, radiation, and other cancer treatments can also cause pain in the lymph nodes.

Lymphoma and leukemia are the most common types of cancer which can cause pain under your arms.

17. Rheumatoid arthritis

Sometimes this disease can cause inflammation and swelling in the inner joint tissues, including those in the armpits.

18. Hidradenitis Suppurativa

Inflammation of the sweat glands related to hair follicles is called Hidradenitis Suppurativa. First, you may notice blisters or pimple-like bumps appearing in your armpits, gradually turning into boils and cysts. Over time, they can weep, break, and form under skin tunnels.

In such condition, it’s best to seek medical attention to avoid potential infection and scarring.

When to See a Doctor?

Although in most cases armpit pain is not serious, you should when to see a doctor. If the following symptoms accompany your pain, visit your doctor immediately.

  • Lump in armpits that varies in sizes
  • Difficulty breathing
  • Intense and sudden pain in the area
  • Tightness in chest
  • Chest pain that radiates in your armpit
  • Fever and night sweats
  • Constipation
  • Unexplained weight loss