Acne Causes

Acne Causes

Several factors contribute to the development of acne. The primary problem is the abnormal development of cells inside the hair follicle, leading to the formation of a plug or blackhead (comedo). The plug inhibits the normal movement of hair, skin cells and grease (sebum), resulting in enlargement and eventually rupture of the hair follicle. A ruptured hair follicle spills its contents of oil and debris into the skin where it leads to swelling and causes redness (inflammation).

• Propionibacterium acnes, a type of bacteria that normally lives in the skin hair follicles, also plays a role in acne. These bacteria produce substances that cause redness and irritation (inflammation). They also make enzymes, which dissolve the sebum from the oil glands in the skin into irritating substances. These substances also make the inflammation worse.


• Certain hormones called androgens are an additional factor in causing acne. Androgens are male hormones that are present in both men and women but are higher in men. Androgens do two things: First, they enlarge the sebaceous glands in the skin. Second, they cause these glands to increase sebum (oil) production. The increased sebum production exacerbates plug formation and serves as more "food" for the bacteria. Androgens surge at puberty, which is why teens develop armpit and pubic hair and why boys develop facial hair and deeper voices. This hormonal surge also contributes to the development of acne in teens.


• Estrogens, which are the female hormones, actually can help to improve acne in girls. A woman's monthly menstrual cycle is due to changes in the estrogen levels in her body. This is why acne in a female may get better and then get worse as she goes through her monthly cycle. A doctor may recommend acne treatment with birth control pills, which contain the helpful estrogens.


• It is now also believed that severe acne can run in some families. This may be due to genetic factors that has not yet been discovered.


• Anatomy of the hair follicle: Hair follicles exist on virtually all skin except for the palms of the hands and soles of the feet. Inside the follicle, the hair extends up from the deep layers of the skin and comes out of a pore. Near the surface, the oil gland (sebaceous gland) enters the hair follicle where it empties sebum at a relatively constant rate. The sebum lubricates the skin and provides a protective barrier to prevent drying. Skin on the face, chest, and back has an especially large number of sebaceous glands. These are the areas where acne occurs.


• Acne lesions: There are two major types of acne lesions: noninflammatory and inflammatory. Noninflammatory acne lesions include blackheads (open comedones) and whiteheads (closed comedones). Open and closed comedones along with papules and pustules are referred to as papulopustular acne, a form of inflammatory acne. Nodular acne is the most severe form of inflammatory acne.


• Noninflammatory acne: Open comedones result from the enlargement and dilation of a plug that forms from oil and skin cells inside the hair follicle.


• The hair follicle pore remains open, exposing a black plug (known as a blackhead). The dark color is not dirt inside the pore. Instead it is the oil inside the pore, which has become exposed from the outside air.


• A closed comedo forms if the hair follicle pore remains closed. The plug in a closed comedo or whitehead is therefore not exposed to the outside air, and no black color develops. The closed comedo simply appears as a tiny, sometimes pink bump in the skin.


• Inflammatory acne: Inflammatory acne lesions consist of red blemishes, pimples also called zits (papules, pustules), and larger, deeper swollen tender lesions (nodules).


• Papules are closed comedos, which have become red, swollen, and inflamed.


• Pustules are closed comedos, which become inflamed and begin to rupture into the skin forming pustular heads of various sizes.


• Nodules represent large, tender, swollen acne lesions, which have become intensely inflamed and rupture under the skin. If untreated, these can produce deep scarring.