Diseases & Conditions


Overview, Causes, & Risk Factors

Acne is a common skin condition in which the hair follicles become clogged with sebum. The hair follicles are the openings around the hair shaft, and sebum is the oil produced by the glands within the follicle. The clogged follicles cause pimples and inflamed infected abscesses, or collections of pus.

What is going on in the body?

Acne tends to develop in teenagers because of an interaction among hormones, sebum, and bacteria. During puberty, the glands in the skin produce excessive sebum. In acne-prone skin, the sebum and dead skin cells clog the hair follicles and form comedones, or clogged pores.

What are the causes and risks of the condition?

Acne is caused by 4 factors:

  • hormones, particularly the hormone called androgen
  • increased production of sebum, the oily substance within the hair follicles
  • changes in the lining of the hair follicles
  • bacteria, including organisms that normally live on the skin surface. When these bacteria are trapped within the hair follicles, they can cause infections and inflame the follicles.
  • Virtually every adolescent experiences some comedones. Generally, acne starts at about age 10 to 13, and lasts for 5 to 10 years. Around the age of 14 or 15, 40% of adolescents have acne that is serious enough to require a visit to a healthcare provider. Acne occurs in both male and female adolescents, but males are more likely to have a severe form of acne. Some people develop acne for the first time as an adult.

    Certain forms of acne tend to run in families. If an adolescent's parents or older siblings have severe acne, the adolescent has a higher risk of developing severe acne.

    Risk factors for development or worsening of acne include the following:

  • makeup and skin care products, which can clog the hair follicles
  • menstrual cycles in females. A female is more likely to have flare-ups of acne around the time of her period, when her glands are more sensitive to the hormone androgen.
  • airborne grease, such as in a fast-food restaurant
  • routine exposure to products, such as motor oil in an automotive shop
  • rubbing and friction of the skin by hair, clothing, or sporting equipment

  • Symptoms & Signs

    What are the signs and symptoms of the condition?

    Acne may occur on a person's face, neck, chest, back, shoulders, scalp, and upper arms and legs. Comedones, or clogged pores, are the first signs of acne. There are 2 types of comedones:

  • blackheads, which are incompletely clogged pores capped with blackened dust or debris
  • whiteheads, which are completely clogged pores
  • A comedone may also break through the pore wall underneath the skin and release its contents. This causes a pimple or pustule. If this substance is released deep into the skin it will cause a cyst, which is a small, pus-filled bump beneath the skin.

    Diagnosis & Tests

    How is the condition diagnosed?

    Acne is diagnosed when blackheads, whiteheads, pimples, pustules, or cysts are seen on the skin.

    Prevention & Expectations

    What can be done to prevent the condition?

    Measures to prevent or minimize acne include the following:

  • washing the face twice a day with a mild soap and patting it dry
  • avoiding any picking, squeezing, or popping of comedones, pimples, pustules, and cysts. This type of manipulation actually makes the acne worse.
  • selecting skin care products labeled as noncomedogenic, which means they don't clog pores. Look for the noncomedogenic label on makeup, foundation, moisturizers, and creams.
  • avoiding prolonged exposure to oil and grease in settings such as fast-food restaurants and automotive shops
  • avoiding unnecessary friction from hair, clothing, or sporting equipment
  • What are the long-term effects of the condition?

    Long-term acne can lead to permanent scarring. It can also decrease a person's self esteem and confidence.

    What are the risks to others?

    Acne is not contagious and poses no risk to others.

    Treatment & Monitoring

    What are the treatments for the condition?

    The most important thing in treating acne is to keep the skin gently cleansed and pores unclogged. Over-the-counter products for acne include the following:

  • cleansers, which should be used only if recommended by the healthcare provider. Many cleansers may aggravate the acne, especially if the person vigorously scrubs the area.
  • benzoyl peroxide, which can be a cream, gel, or lotion. Benzoyl peroxide works by killing the bacteria that can inflame the hair follicle.
  • salicylic acid, which can be a lotion, cream, or pad. Salicylic acid helps unclog pores and prevent abnormal shedding of skin cells.
  • Prescription medications used to treat acne include the following:

  • antibiotics, such as tetracycline and erythromycin, which can be taken orally or applied to the skin. Antibiotics kill bacteria on the skin and within the hair follicles.
  • retinoids, a class of medications that are derived from vitamin A. Retinoids are used for moderate to severe acne. They work by reducing sebum production, killing bacteria, and making skin growth and shedding normal. These medications are generally applied to the skin. Isotretinoin, also known as Accutane, is a powerful oral medication used for severe acne. It is currently the subject of investigation by the Food and Drug Administration, or FDA, for a host of side effects.
  • oral contraceptives, which are female hormones used as birth control pills. These may be prescribed to females with acne to offset the effect of androgen on the skin.
  • Removal of comedones can also help to treat acne. This needs to be done with a special instrument to minimize skin injury. Cortisone may also be injected directly into the skin lesion in certain cases for large, painful cysts.

    What are the side effects of the treatments?

    Excessively dry and red skin is the most common side effect of medications applied to the skin for treatment of acne. Oral antibiotics may cause stomach upset, allergic reactions, and a sensitivity to sunlight. They may also decrease the effectiveness of oral contraceptives.

    Isoretinoin, or Accutane, has been linked to birth defects and miscarriage when used by a pregnant woman. An advisory committee of the Food and Drug Administration has proposed a mandatory registry for women who take isotretinoin. The FDA has also received reports of depression and suicide in individuals taking the medication. At the request of the FDA, the medication's manufacturer has also notified healthcare providers that people taking isotretinoin must receive a medication guide and sign an informed consent document.

    What happens after treatment for the condition?

    Most treatments need to be continued on an ongoing basis to be effective. One exception is isotretinoin, which is used for 16 to 20 weeks.

    How is the condition monitored?

    Any new or worsening symptoms should be reported to the healthcare provider.


    Author:Lynn West, MD
    Date Written:
    Editor:Ballenberg, Sally, BS
    Edit Date:02/28/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:07/27/01