You may develop a boil in the armpit due to a bacterial infection due to shaving or excessive sweat. But it can also occur more often if you have a weakened immune system.
A boil (also known as a furuncle) is caused by an infection of a hair follicle or oil gland. The infection, usually involving the bacterium Staphylococcus aureus, builds up in the follicle in the form of pus and dead skin. The area will become red and raised, and will slowly grow as additional pus builds up within the lesion.
While unsightly and uncomfortable, most boils are not life-threatening and may open and drain on their own within two weeks. If the boil under your arm grows rapidly or does not improve in two weeks, see your doctor. Your boil may need to be surgically lanced (opened by cutting a small incision).
What causes armpit boils?
Boils under the arm occur when a hair follicle becomes infected. This may occur due to:
- Excessive sweating. If you sweat more than normal due to the weather or physical activity, but you don’t clean yourself properly, you may be more susceptible to infections such as boils.
- Shaving. Your underarm is a place where sweat and dead skin can build up. If you shave your armpits often, you could have higher likelihood of contracting a bacterial infection in your armpit. When you shave, you may be accidentally creating openings in the skin under your arms which can allow bacteria easier access.
- Poor hygiene. If you do not wash under your arms regularly, dead skin can build up which may contribute to the development of boils or pimples.
- Weak immune system. If you have a weak immune system, your body may be less able to fight off a bacterial infection. Boils are also more common if you have diabetes mellitus, cancer, eczema or allergies.
In the video below, you can watch a man draining a boil under his arm at home. Please note that this video is for viewing purposes only. We strongly advise against attempting this yourself and always recommend seeking professional medical assistance.
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