Armpit Pain: 9 Common Causes (& What To Do)

Armpit pain can occur for many reasons, like a swollen lymph node, hidradenitis suppurativa or from a muscular injury to the pectoral chest muscles. 

Nonetheless, if armpit pain radiates to the arms or is accompanied by other symptoms like fever, general malaise, excessive fatigue, breast pain or breast discharge, it can be a sign of breast cancer. 

Therefore, if your armpit pain does not resolve and occurs with other symptoms, you should see your doctor for assessment and for treatment as indicated. 

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The most common causes of armpit pain are:

1. Swollen lymph nodes

Swollen lymph nodes in the armpit usually appear due to an infection or inflammation near the armpit area. The lymph nodes are part of the immune system and help to fight infections by attacking and destroying the germs that are transported by the lymphatic fluid.

Having a lump in the groin, neck, or armpit is also called adenopathy or lymph node disease. In most cases, it represents a mild and temporary inflammation, but it can also be a sign of a more serious diseases (like cancer or autoimmune diseases) when the swollen lymph node persists for over 1 month or if it grows more than 2 cm (close to an inch).

What to do: Treatment is generally not necessary, and rest and hydration to support a mild irritation is usually sufficient. However, diagnosis of the inflammation or infection remains important, as it may be necessary to take antibiotics. Analgesic or anti-inflammatory drugs, as prescribed by the doctor, may also be recommended to relieve pain or tenderness in the area.

2. Muscle strain

Overexertion or injury to the chest and arm muscles from activities like tennis, weight training, volleyball, or baseball can also cause armpit pain.

What to do: This pain can be easily relieved with rest and and a cold compress on the affected area for about 15 to 20 minutes, three times a day. Analgesic drugs, like acetaminophen, and anti-inflammatory drugs, like ibuprofen, can also be used to relieve pain and inflammation.

3. Sebaceous cyst 

The appearance of a sebaceous cyst in the armpit mainly occurs due to inflammation of a follicle root, or a skin injury from shaving, for example.

Generally speaking, a sebaceous cyst will not cause any major health problems, It is characterized by a small pimple filled with sebum. It may be sensitive to palpation, but should not be painful. Cysts that become inflamed, however, can become red, hot and much more uncomfortable. 

What to do: In these cases, you should not try to rupture or pop the cyst, as it can worsen inflammation. See a dermatologist for assessment and treatment, which may involve surgical removal under local anesthesia. If signs of infection are present, the doctor may additionally prescribe antibiotics. 

4. Hidradenitis suppurativa

Hidradenitis suppurativa is characterized by the presence of lumps in the armpit or groin area caused by an inflammation in the sweat glands. This condition may also result in several small wounds, mainly in areas of the body that produce a lot of sweat, such as armpits, groin, anus, and buttocks.

The symptoms associated with this problem are itching, burning, and excessive sweating, as well as the affected skin areas becoming swollen, stiff, and red. These nodules can also burst, releasing pus before the skin heals. 

What to do: There is no cure for hidradenitis, but symptoms can be managed with antibiotic creams and corticosteroid injections in the affected area. Drugs that control the production of hormones can also be prescribed, especially in women, and surgery to remove the area of the skin with defective glands may be necessary in more severe cases.

5. Allergic reaction

An allergic reaction or rash is associated with local irritation, caused by deodorant use, soaps, laundry detergents or synthetic fabrics (like lycra, polyester or nylon). In addition to mild armpit pain, you may also notice redness, swelling and heat in the area.

What to do: Armpit pain associated with a skin reaction can be treated by cleansing the skin thoroughly to remove any irritating substances. You should use mild soaps and hypoallergenic products to prevent worsening. Active irritations can be treated with soothing lotions containing aloe vera, chamomile and lavender. You can also apply cold compresses. 

If your symptoms do not improve within a few hours, you should see a dermatologist for further assessment. 

6. Psoriasis

Psoriasis is an inflammatory autoimmune disease that is chronic and affects the skin in various areas of the body, including the armpit. This condition is associated with red rashes that can dry-up, itch, burn and cause pain. Read more about psoriasis symptoms and what can cause them. 

What to do: There is no specific treatment for psoriasis, although symptoms can be adequately managed to improve quality of life. A dermatologist can prescribe corticosteroid ointments, as well as light therapy and a psoriasis diet

7. Intertrigo

Intertrigo is a fungal skin infection caused by Candida albicans fungus. This condition is associated with an overgrowth of this fungus, which naturally occurs on the skin, and is usually caused by persistent friction and moisture in the area. It leads to symptoms like redness, pain and itching, and is most commonly seen in the armpits.

What to do: Treatment for intertrigo should be guided by a dermatologist and depends on the characteristics of the lesions. The doctor will typically prescribe barrier creams to reduce further friction and promote healing. The doctor may also prescribe antifungal ointments to manage overgrowth. 

8. Lymphoma

Lymphoma is a type of cancer that affects lymphocytes of the immune system. It usually starts with the emergence of lumps in the armpits, groin, neck, stomach, intestine or skin that can cause symptoms such as pain, fever, general malaise, and tiredness. 

What to do: Treatment depends on the type of lymphoma, its stage, the affected area, and the general health status of the patient. It may include chemotherapy, radiation therapy, or bone marrow transplant. Hodgkin’s lymphoma is more likely to be cured than Non-Hodgkin's lymphoma, as treatment is more effective when the disease is discovered and treated early.

9. Breast cancer

Breast cancer is one of the most common types of cancer in women. Although it normally doesn't cause symptoms in its early stages, a hardened lump felt upon palpation of the armpit may indicate the presence of malignancy.

These lumps may appear swollen or cause pain that radiates to the arm, and other symptoms like sore breasts and nipple discharge can also occur. 

What to do: Breast cancer can be treated and cured depending on the type and stage. Prevention through self-examination and mammograms is very important.