A cyst is a pouch or pocket of tissue that can be filled with fluid, pus, air or other substances. In most cases cysts on the skin are a sign of infection or the sebaceous glands becoming clogged. Cysts specifically located in the armpit can be caused by irritation in this area as well as a potential infection. Though they are typically harmless and will disappear on their own without treatment, it is important to note what may be causing these cysts so you can apply any treatment that might be necessary to remove them.

Causes of Armpit Cyst

1. Shaving or Antiperspirants

Lumps in the armpits are typically caused by an irritation brought on by using antiperspirants or shaving this area. These products can block the sebaceous glands, causing an infection that leads to a lump forming. Adolescents that are new to shaving their bodies are more likely to develop this condition.

2. Infections

Bacterial infections including staphylococcal or streptococcal infections can affect the lymph nodes near the armpits, causing a lump to appear. A woman’s breast tissue can also develop a bacterial infection which may cause a lump near the breasts. Chronic fungal infections on the skin near the armpit, known as sporotrichosis can cause cysts to appear. Viral infections including chickenpox, shingles, HIV/AIDS or mononucleosis may also cause cysts to appear near the armpits.

3. Vaccinations

Vaccinations for typhoid or smallpox can cause cysts to appear. Some drugs used to vaccinate for diseases like rubella, measles or mumps can cause an allergic reaction, causing cysts.

4. Autoimmune Disorder

Autoimmune disorders can cause your body to begin attacking healthy cells. Conditions like rheumatoid arthritis, juvenile rheumatoid arthritis and systemic lupus erythematous have been known to cause cysts to appear in the armpits.

5. Other Causes

Lipomas, armless cysts or breast tissue that extends into the armpit can cause lumps to appear. Cancerous cells throughout the body can become metastasized in the lymph nodes near the armpit, causing a lump to form. Other types of cancer such as leukemia, Hodgkin’s lymphoma and non-Hodgkin’s lymphoma can cause lumps to form in the underarms.

Diagnosis of Armpit Cyst

Any lumps that appear on the body, particularly those that appear with without explanation should be examined to determine the underlying cause. A doctor can perform a test to determine exactly what is causing the cyst, but there are a few examinations you can perform at home to get a better idea of what might be causing the cyst.

1. Physical Exam

Make note of the characteristics of your cyst. In most cases, cysts are the same color as your skin. They tend to be small, typically not getting larger than 2 inches in diameter. Those that are not infected should not cause you any pain. In some cases, cysts will look like a skin pore that has been squeezed or ruptured accidentally or look like a blackhead. They may also leak a cheese-like substance or pus that has a foul odor.

2. Wiggle Test

Take the thumb and forefinger and gently squeeze the lump in your armpit, moving it back and forth. If the lump wiggles easily it is more likely to be a cyst because lumps caused by an infection are less easy to move.

Treatments for Armpit Cyst

1. Medical Treatments

• Antibiotics can be applied to the cyst to rid the body of infectious bacteria contributing to your condition.
• Cysts that are filled with liquid or those that are large can be drained with a needle to help relieve the pressure. Do not squeeze or drain the lump at home. This can lead to an infection.
• If the lump in the armpit is inflamed your doctor may inject the area with a corticosteroid to bring down the swelling.
• Cysts that cause discomfort, are painful or hinder your ability to perform daily activities can be removed with a surgical procedure. Your doctor may also remove a cyst if they suspect the lump in your armpit may be cancerous so a biopsy can be performed.
• Laser treatments can help to vaporize the cyst, reducing potential scarring. This method is typically used to eliminate cysts that are located in sensitive areas.

2. Home Remedies

• Those suffering from sebaceous cysts can create a warm compress by dipping a towel in warm water and ringing out the excess liquid. Holding this compress on the cyst will help to the cyst drain. However, do not attempt to use this method on cysts that are infected.
• If the cyst in your armpit has ruptured this puts you at a serious risk of developing an infection. Once the rupture has occurred, wash the area carefully with soap and water. Use a cotton ball to apply an antibacterial liquid. Gently cover the area with a gauze pad to keep dirt and other irritants away from the wound until your doctor can inspect it.
• Use an antibacterial liquid to carefully wash the cyst and the surrounding area to help prevent further irritation.