Acne is a skin disorder resulting from the blockage of hair follicles in the skin. Excess cells produced in the follicle combine with sebum, an oily substance secreted by glands connected to the follicle. When a plug forms in the follicle and is infected with bacteria, a pimple erupts.
Acne is a skin problem commonly associated with teenagers, but it can also occur in children, adults in their thirties or forties, and women around the time of menopause. It is most likely to appear on the parts of the body with the largest number of hair follicles—the face, chest, upper back, and (in some people) upper arms. Some forms of acne are
relatively mild. The less severe form consists of comedones, which are hair follicles blocked by plugs of sebum. If the comedo is open to the air on the skin surface, the sebum grows darker, giving the comedo a blackish appearance. This type of comedo is called a blackhead; its dark color is not caused by dirt. If the comedo is not open, the sebum inside produces a whitish bump called a whitehead. Both whiteheads and blackheads can remain in the skin for weeks. Bacteria that normally live on the skin can grow inside the plugged follicles. The bacteria then secrete various chemicals that prompt an inflammatory response from the person's immune system. The plugged follicle may eventually burst, allowing the bacteria, the sebum, dead skin cells, and dead white blood cells to leak into nearby skin, causing reddened papules (small pink bumps), pus-filled pimples, or cysts (deep pus-filled lesions that are sore to the touch and can cause scarring).
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), about 80 percent of people in the United States develop acne at some point between the ages of eleven and thirty. Boys are more likely than girls to develop acne during adolescence; however, among adults, women are more likely than men to suffer from acne. Twelve percent of women and 5 percent of American men at age twenty-five have acne; at age forty-five, 5 percent of both men and women still have acne. Some older women are troubled by acne again during menopause. Acne is equally common among people of all races and ethnic groups in the United States.
Acne is thought to result from the interaction of four factors that are most common in adolescents but can occur in adults as well. The first is the rise in production of hormones known as androgens, which are hormones produced by the adrenal glands (located on top of the kidneys) and are present in women as well as in men. The hormonal
increase triggers the rapid multiplication of the cells lining the hair follicles on the face, chest, upper back, and shoulders. When these cells are produced faster than the follicle can shed them, they form a plug that blocks the follicle and keeps the sebum produced by the glands connected to the follicle from reaching the surface of the skin. The mixture of oily sebum and dead skin cells in the plug allows bacteria known as Propionibacterium acnes, which normally live on the skin, to grow inside the follicle. The chemicals produced by the bacteria then trigger an inflammatory response from the body's immune system. White blood cells are drawn to the area around the plugged follicle to fight the bacteria. If the plugged follicle bursts, the inflammation may spread, leading to the pus-filled pimples and cysts of severe acne. Some people are more likely than others to develop acne.
Risk factors include:
- Heredity. People with a family history of acne are more likely to develop acne at a relatively early age and to have more severe breakouts.
- Changes in the body's hormonal levels. Pregnant women, women in the week preceding the menstrual period, women in early menopause, and teenagers of either sex are more likely to develop acne. People who use steroids for bodybuilding, medications containing cortisone, antiepileptic medications, or lithium are also more likely to have acne.
- Exposure to greasy or oily substances (deep-fat fryers or similar cooking equipment, lubricating oils and grease guns, oil-based paints) at home or in the workplace.
- Clothing or athletic equipment (backpacks, shoulder straps, helmets, headsets, etc.) that puts pressure on skin or rubs against it.
- Climate. People who live in locations with high humidity or high levels of air pollution are more likely to develop acne.
Mild acne is not painful; the pustules and cysts of severe acne, however, may be sore to the touch. In addition, the psychological effects of acne can be very painful for many patients, particularly adolescents.
In most cases the doctor diagnoses acne on the basis of the appearance of the skin. Primary care doctors can usually treat milder cases of acne. People with more severe cases are usually referred to a dermatologist, who is a doctor who specializes in diagnosing and treating skin disorders. In a very few cases, women whose skin problems may be related to abnormally high levels of androgens may be given a hormone test.
Treatments for acne work in one or more of four ways:
- lowering the skin's production of sebum
- speeding up the removal of dead skin cells
- fighting bacterial infection
- reducing the skin's inflammatory response to infection
Some medications used to treat acne are topical (applied to the skin) while others are taken by mouth. Some can be purchased over the counter, but others require a prescription from the doctor.
Self-Care for Acne
To care for skin troubled by acne, people should:
- Cleanse the skin gently twice a day with a cleanser recommended by the doctor, and rinse the cleanser thoroughly.
- Wash the face after exercise or other activities that lead to heavy sweating.
- Wash the hair regularly, particularly if the facial skin is oily. Avoid rubbing or touching the face, or squeezing the pimples. Pinching or picking at acne blemishes can lead to scarring.
- Men who need to shave should shave carefully and use the type of razor that works best for them, whether electric or safety blade models. They should be careful when shaving to avoid nicking or cutting the pimples.
- Avoid unnecessary sun exposure, as many acne medications increase the risk of sunburn.
- Women who use cosmetics should choose them carefully and avoid oil-based products. All makeup should be removed before bedtime.
- Wear loose-fitting clothing that does not trap sweat or rub against the skin helps to reduce the risk of acne breakouts on the neck, upper arms, and upper back.
The specific medications or other treatments that a doctor might recommend depend on the severity of the acne, the extent of scarring, and the possibility of side effects for specific patients. Mild acne is commonly treated with topical medications in soap, cream, or lotion form, most of which do not require a prescription. They include various combinations of sulfur, benzoyl peroxide, salicylic acid, and a few other drugs to dry up excess sebum, kill bacteria, and speed up removal of dead skin cells. These nonprescription products may take about eight weeks to produce results. Moderately severe acne may be treated with prescription medications, including antibiotics to be taken by mouth along with using topical creams,
lotions, or gels that also require a prescription. These products may cause stinging, reddening, or peeling of the skin in some people; however, patients usually start seeing improvement in about four weeks.
Patients with severe cystic acne are usually referred to a dermatologist for specialized treatment. A drug that is often prescribed for severe acne is Accutane, a drug derived from vitamin A that shrinks the size of the oil glands that produce sebum. Accutane must be taken only under careful supervision by a doctor, however, as it can cause serious side effects, including depression and an increased risk of a disease called irritable bowel syndrome. In addition, Accutane cannot be given to women who may become pregnant because it can cause birth defects in children. Other treatments for acne include phototherapy, which is the use of light waves to kill bacteria; and laser therapy, which helps to dry up the oil glands in the skin.
People with severe scarring from acne can have their scars treated with dermabrasion or laser therapy to make them less noticeable. Very large scars can be removed surgically if necessary.
The prognosis for acne depends on its severity. Most people's skin clears up by the early adult years, and newer techniques for treating scars lead to good results for most people. Nonetheless, some people have longstanding psychological problems—usually social isolation—as the result of severe acne in adolescence.
Acne is difficult to prevent entirely, particularly for people who have inherited a family tendency to develop severe acne in adolescence. However, careful attention to proper skin care can reduce the severity and frequency of breakouts.
Current research focuses on possible ways to prevent skin inflammation caused by Propionibacterium acnes. Scientists in Germany have recently identified the bacterium's genome (genetic information), which may lead to the development of new medications to eliminate the bacterium from acne-troubled skin. Other research is directed toward developing lasers that can treat acne scarring with less damage to the outer layers of skin.
SEE ALSO Irritable bowel syndrome; Sunburn
WORDS TO KNOW
Androgens: The group of male sex hormones secreted by the outer portion of the adrenal gland; they are found in women as well as men.
Comedo (plural, comedones): The medical term for a whitehead or blackhead.
Dermabrasion: Technique for making acne scars less noticeable by removing the top layer of skin with a rapidly rotating wire brush or a sandy material.
Dermatologist: Doctor who specializes in treating disorders of the skin.
Follicle: Small canal in the skin surrounding the root of a hair.
Phototherapy: Method of treating skin disorders by exposing the affected skin to daylight or to specific wavelengths of visible or ultraviolet light.
Sebum: An oily lubricant secreted by glands in the skin.
Systemic: Referring to a disease or disorder that affects the entire body. Acne is not a systemic disease.
Topical: Referring to a medication applied to the skin or the outside of the body.
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