Pimples are commonly caused by infected hair follicles or clogged pores. They are most likely to appear on your face, back, chest and shoulders -- where the oil glands in your skin are most active -- but can occur anywhere on your body, including your upper arms. Pimple-like bumps on your arms can also be caused by other conditions, such as keratosis pilaris, and while there may not be a surefire cure, a number of treatments can ease your symptoms.
A pimple occurs when one of your skin's pores or sebaceous glands -- which secrete sebum to lubricate your skin -- becomes blocked or infected with bacteria, excess oil or a hair. This causes the site to become inflamed and a small head of pus forms as your body fights the blockage. It's not unusual for a rash of pimples to appear on your upper arms -- a condition sometimes referred to as arm acne -- and you can use the same treatments as for your face.
Arm Pimple Treatments
While they may not prevent or completely cure the condition, some methods can reduce the size and longevity of the pimples. On Medical News Today, Christian Nordqvist suggests washing your arms twice a day with a mild soap and warm water -- but avoid scrubbing as this can make the condition worse. Over-the-counter solutions which contain benzoyl peroxide, such as Clearasil, may also help. Benzoyl peroxide is an antibacterial that removes dead skin cells so there's less chance of them causing a blockage. However, this ingredient can lead to overly dry skin, so use it sparingly until you have gauged your skin's reaction.
Nordqvist also recommends that you avoid squeezing your pimples because this can force the blockage deeper and may create a permanent scar on the skin's surface.
Keratosis pilaris can also cause pimple-like bumps to appear on your upper arms. According to MedlinePlus, it is caused by a buildup of the protein keratin, which plugs your hair follicles. Hair gets trapped under the skin's surface, contributing to inflammation which produces small red bumps on your skin. The condition is believed to be hereditary and usually appears in the first 10 years of life and may worsen during adolescence before easing off toward adulthood, says the Patient UK health website.
Treatment for Keratosis Pilaris
Although keratosis pilaris may create an undesirable appearance, it is not a serious condition and usually disappears as you move into adulthood. However, some treatments may help reduce your symptoms. Make sure your skin doesn't become overly dry by taking warm rather than very hot baths and showers. Very gently exfoliating may help, as can using a lotion containing salicylic acid, which removes dead skin cells.