Acne is a skin condition that affects areas containing the largest oil glands, including the nose, forehead, cheeks, chin, back, and trunk. It is caused by a disorder of the oil glands that results in clogged pores and outbreaks of lesions commonly known as pimples. Acne affects between 17 million and 45 million people, making it the most common skin disease in the United States. While it tends to last longer in females, males are more likely to get acne and tend to have more severe cases than do females. Some infants may develop acne, but it is most common in adolescents and it generally disappears by age 30. Although it is not a serious health threat, severe acne can be painful and may cause permanent scarring, which can be upsetting for people who suffer from the condition. An estimated $100 million is spent annually on over-the-counter products to treat acne and reduce the pain, scarring, and emotional distress that can be associated with it.
Signs and Symptoms
There are various types of acne lesions:
• Comedone — general term for an enlarged hair follicle plugged with oil and bacteria. This is the first and smallest type of lesion. It is often referred to as a microcomendone because it cannot be seen by the naked eye.
• Open comedone (blackhead) — a plugged follicle that reaches the surface of the skin. Although dark in appearance, blackheads do not indicate the presence of dirt.
• Closed comedone (whitehead) — a clogged follicle that stays beneath the skin. Whiteheads usually appear on the skin as round, white bumps roughly 1 to 2 mm in diameter.
• Papules — inflamed lesions that appear as small, pink bumps on the skin
• Pustules (pimples) — inflamed pus-filled lesions that are red at the base
• Cysts and nodules — large, inflamed, pus-filled lesions that are lodged deep and can drain, causing pain and scarring
Lesions can cause scars ranging from small, depressed pits to large elevated blemishes, depending on the severity of the condition and the individuals skin type.
Causes
Acne is a disorder of the skins oil glands. Oil glands make an substance called sebum that normally rises up through a hair-containing canal called a follicle and empties onto the skin surface. The precise cause of acne in newborns is not known, but some researchers speculate that it may be due to the transfer through the placenta of hormones from the mother or of acne-causing medication (such as lithium and phenytoin) that the mother may have been taking. During adolescence, rising hormone levels are thought to increase the number of oil glands and the amount of sebum they produce. The increased production of sebum causes blockage of hair follicles, leading to the formation of small bacteria-filled cysts called comedones. If these comedones remain intact and no not rupture, they can progress into open comedones (whiteheads) or closed comedones (blackheads). When comedones rupture, an inflammatory reaction occurs and can spread into the surrounding tissue. Papules, pustules, cysts, and nodules are all forms of inflammatory lesions.
Risk Factors
The following may cause or worsen acne:
• Family history of acne
• Greasy/oily cosmetic or hair products containing vegetable or animal fats
• Hormonal changes associated with adolescence, pregnancy, or menstruation (acne tends to flare up 2 to 7 days before menstruation begins)
• Certain medications such as corticosteroids, androgens, oral contraceptives, lithium, halogens, isoniazid, phenytoin, phenobarbital, and high levels of iodine (such as from kelp)
• Environmental irritants such as industrial cutting oils, tar, wood preservatives, sealing compounds, and other pollutants
• Sweating and friction, such as from headbands, back packs, bicycle helmets, or tight collars
• High levels of humidity
• Squeezing and picking comedones
Although still controversial, some researchers believe that stress and sun exposure can also cause or aggravate existing acne. This may be due to the use of oily sunscreens however, as some people with acne actually experience improvement in symptoms with exposure to the sun.