What is the cause of acne?

What is the cause of acne?

Acne is the most common skin condition that people experience. Most people develop acne to some degree, but it primarily affects teenagers undergoing hormonal changes. Acne might be mild (few, occasional pimples), moderate (inflammatory papules), or severe (nodules and cysts). Scarring can occur. Treatment depends on the severity of the condition.

Acne is primarily a hormonal condition driven by male hormones, which typically become active during the teenage years. Sensitivity to such hormones — combined with surface (skin) bacteria and lipids (fatty acids) within sebaceous (oil) glands — yields acne. Common sites for acne are the face, chest, shoulders, and back—the sites of oil glands.

Acne lesions include comedones (whiteheads, blackheads), papules and pustules (small bumps, often with scarring), nodules, and cysts, often followed by scarring.

Although acne is essentially a normal physiologic occurrence, certain conditions might aggravate the disease.

• Fluctuating hormone levels around the time of menses (women)
• Manipulating (picking/prodding) acne lesions
• Occlusive clothing and headgear, such as hats and sports helmets
• Air pollution and certain weather conditions, especially high humidity

What is the treatment for acne?

Only three medicines have proven to be effective for the treatment of acne—benzoyl peroxide, retinoids, and antibiotics. Most patients require at least one or two agents, depending on disease severity.

• Benzoyl peroxide is available as an over-the-counter product (such as Clearasil, Stridex) and by prescription (e.g., Benoxyl, PanOxyl, Persagel). It targets surface bacteria, which often aggravate acne. Irritation (dryness) is a common side effect.
• Retinoids (vitamin A derivatives) — such as Retin-A, Differin, and Tazorac — are comedolytic, meaning they lyse or "break up" comedones (blackheads and whiteheads), the first lesions of acne. Most patients are candidates for retinoid therapy. The most common side effect is irritation.
• Antibiotics, either topically applied to the skin (clindamycin, erythromycin) or taken systemically (tetracycline and its derivatives) control surface bacteria that aggravate and often foster acne. Antibiotics are more effective when combined with benzoyl peroxide or retinoids.

The oral retinoid isotretinoin (Accutane) is reserved for those patients with severe (nodular or cystic) disease. Accutane shrinks the size of oil glands, the anatomic origin of acne. Without active, plump oil glands, acne actively diminishes. Side effects can be worrisome (dry skin, elevated lipids) and even devastating (birth defects). Women of childbearing age must practice birth control before and during treatment with Accutane, and for several months afterward, often a year. The use of Accutane requires rigorous testing (lipids, pregnancy) and follow-up for the prescribed period (five months).

Hormone therapy might be helpful for some women with acne, especially for those with signs and symptoms (irregular periods, thinning hair) of androgen (male hormone) excess. The hormone therapy consists of low-dose estrogen and progesterone (birth control pills).