Is a pimple an infection?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
A pimple is a type of small local infection. When a hair follicle is blocked by oil and dead skin cells, local bacteria can multiply, which causes the immune system to respond. A pimple is the visible result of this response. Watch the animation to learn more about pimples and your immune system.

A pimple is a collection of pus in the hair follicle that may be visible from the surface (a "pustule") or may be located deeper and show only a red bump (a "papule" or "nodule").

There are different types of pimples. The most common type are acne pimples, which are usually on the face, upper chest, back, or shoulders. This is not an infection -- acne pimples do not contain harmful bacteria, and cannot be spread from one area of the body to another, or from one person to another. Even when someone has a serious complexion problem, it's important to remember that acne is not contagious. The reason for pus formation is that normal skin bacteria, called Propionibacteria acnes, break down the skin oil ("sebum") into free fatty acids, which cause inflammation of the hair follicles that secrete sebum.

Another kind of pimple is an abscess or furuncle. These are usually on areas other than the face, such as the buttocks or thighs. This type of pimple is an infection, because it contains harmful bacteria such as Staphylococcus or Streptococcus, which can spread from one area of the body to another and to other people. To clear these up and prevent the infection from spreading, most doctors prefer to treat these with oral or topical antibiotics.     

All types of pimples are caused when skin oil, called sebum, and dead skin cells clog pores. When this happens, bacteria that normally live on your skin (called P. acnes) may rapidly increase in number inside the clogged pore, causing the pore to become inflamed.

When inflammation reaches deep into the skin, an acne cyst forms. This is the most severe type of acne. Cysts can be very painful. People often see permanent scarring after this type of acne heals.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.