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.
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.
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.
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.
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.
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.
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.
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.
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.