Health Topics
Publication Date October 2001
Questions and Answers About Acne
This fact sheet contains general information about acne.
It describes what acne is and how it develops, the causes of acne, and
the treatment options for various forms of acne. Information is also
provided on caring for the skin. If you have further questions after
reading this booklet, you may wish to discuss them with your doctor.
What Is Acne?
Acne is a disorder resulting from the action of hormones
on the skin's oil glands (sebaceous glands), which leads to plugged
pores and outbreaks of lesions commonly called pimples or zits. Acne
lesions usually occur on the face, neck, back, chest, and shoulders.
Nearly 17 million people in the United States have acne, making it the
most common skin disease. Although acne is not a serious health threat,
severe acne can lead to disfiguring, permanent scarring, which can be
upsetting to people who are affected by the disorder.
How Does Acne Develop?
Doctors describe acne as a disease of the pilosebaceous
units (PSUs). Found over most of the body, PSUs consist of a sebaceous
gland connected to a canal, called a follicle, that contains a fine
hair (see "Normal Pilosebaceous Unit" diagram, below). These units are
most numerous on the face, upper back, and chest. The sebaceous glands
make an oily substance called sebum that normally empties onto the skin
surface through the opening of the follicle, commonly called a pore.
Cells called keratinocytes line the follicle.
Normal Pilosebaceous Unit |
|
The hair, sebum, and keratinocytes that fill the narrow
follicle may produce a plug, which is an early sign of acne. The plug
prevents sebum from reaching the surface of the skin through a pore.
The mixture of oil and cells allows bacteria Propionibacterium acnes
(P. acnes) that normally live on the skin to grow in the plugged
follicles. These bacteria produce chemicals and enzymes and attract
white blood cells that cause inflammation. (Inflammation is a characteristic
reaction of tissues to disease or injury and is marked by four signs:
swelling, redness, heat, and pain.) When the wall of the plugged follicle
breaks down, it spills everything into the nearby skin--sebum, shed
skin cells, and bacteria--leading to lesions or pimples.
People with acne frequently have a variety of lesions,
some of which are shown in the diagrams below. The basic acne lesion,
called the comedo (KOM-e-do), is simply an enlarged and plugged hair
follicle. If the plugged follicle, or comedo, stays beneath the skin,
it is called a closed comedo and produces a white bump called a whitehead.
A comedo that reaches the surface of the skin and opens up is called
a blackhead because it looks black on the skin's surface. This black
discoloration is not due to dirt. Both whiteheads and blackheads may
stay in the skin for a long time.
Other troublesome acne lesions can develop, including
the following:
- Papules--inflamed lesions that usually appear as small, pink
bumps on the skin and can be tender to the touch
- Pustules (pimples)--papules topped by pus-filled lesions
that may be red at the base
- Nodules--large, painful, solid lesions that are lodged deep
within the skin
- Cysts--deep, painful, pus-filled lesions that can cause scarring.
What Causes Acne?
The exact cause of acne is unknown, but doctors believe
it results from several related factors. One important factor is an
increase in hormones called androgens (male sex hormones). These increase
in both boys and girls during puberty and cause the sebaceous glands
to enlarge and make more sebum. Hormonal changes related to pregnancy
or starting or stopping birth control pills can also cause acne.
Another factor is heredity or genetics. Researchers believe
that the tendency to develop acne can be inherited from parents. For
example, studies have shown that many school-age boys with acne have
a family history of the disorder. Certain drugs, including androgens
and lithium, are known to cause acne. Greasy cosmetics may alter the
cells of the follicles and make them stick together, producing a plug.
Factors That Can Make Acne Worse
Factors that can cause an acne flare include:
- Changing hormone levels in adolescent girls and adult women 2 to
7 days before their menstrual period starts
- Friction caused by leaning on or rubbing the skin
- Pressure from bike helmets, backpacks, or tight collars
- Environmental irritants, such as pollution and high humidity
- Squeezing or picking at blemishes
- Hard scrubbing of the skin.
Myths About the Causes of Acne
There are many myths about what causes acne. Chocolate
and greasy foods are often blamed, but foods seem to have little effect
on the development and course of acne in most people. Another common
myth is that dirty skin causes acne; however, blackheads and other acne
lesions are not caused by dirt. Finally, stress does not cause acne.
Who Gets Acne?
People of all races and ages get acne. It is most common
in adolescents and young adults. Nearly 85 percent of people between
the ages of 12 and 24 develop the disorder. For most people, acne tends
to go away by the time they reach their thirties; however, some people
in their forties and fifties continue to have this skin problem.
How Is Acne Treated?
Acne is often treated by dermatologists (doctors who specialize
in skin problems). These doctors treat all kinds of acne, particularly
severe cases. Doctors who are general or family practitioners, pediatricians,
or internists may treat patients with milder cases of acne.
The goals of treatment are to heal existing lesions, stop
new lesions from forming, prevent scarring, and minimize the psychological
stress and embarrassment caused by this disease. Drug treatment is aimed
at reducing several problems that play a part in causing acne: abnormal
clumping of cells in the follicles, increased oil production, bacteria,
and inflammation. Depending on the extent of the person's acne, the
doctor will recommend one of several over-the-counter (OTC) medicines
or prescription medicines that are topical (applied to the skin) or
systemic (taken by mouth). The doctor may suggest using more than one
topical medicine or combining oral and topical medicines.
Treatment for Blackheads, Whiteheads,
and Mild Inflammatory Acne
Doctors usually recommend an OTC or prescription topical
medication for people with mild signs of acne. Topical medicine is applied
directly to the acne lesions or to the entire area of affected skin.
Benzoyl peroxide, resorcinol, salicylic acid, and sulfur
are the most common topical OTC medicines used to treat acne. Each works
a little differently. Benzoyl peroxide is best at killing P. acnes
and may reduce oil production. Resorcinol, salicylic acid, and sulfur
help break down blackheads and whiteheads. Salicylic acid also helps
cut down the shedding of cells lining the follicles of the oil glands.
Topical OTC medications are available in many forms, such as gel, lotion,
cream, soap, or pad.
In some patients, OTC acne medicines may cause side effects
such as skin irritation, burning, or redness. Some people find that
the side effects lessen or go away with continued use of the medicine.
Severe or prolonged side effects should be reported to the doctor.
OTC topical medicines are somewhat effective in treating
acne when used regularly. Patients must keep in mind that it can take
8 weeks or more before they notice their skin looks and feels better.
Treatment for Moderate to Severe
Inflammatory Acne
Patients with moderate to severe inflammatory acne may
be treated with prescription topical or oral medicines, alone or in
combination.
Prescription Topical Medicines
Several types of prescription topical medicines are used
to treat acne, including antibiotics, benzoyl peroxide, tretinoin, adapalene,
and azelaic acid. Antibiotics and azelaic acid help stop or slow the
growth of bacteria and reduce inflammation. Tretinoin, a type of drug
called a retinoid that contains an altered form of vitamin A, is an
effective topical medicine for stopping the development of new comedones.
It works by unplugging existing comedones, thereby allowing other topical
medicines, such as antibiotics, to enter the follicles. The doctor may
also prescribe newer retinoids or retinoid-like drugs, such as tazarotene
or adapalene, that help decrease comedo formation.
Like OTC topical medicines, prescription topical medicines
come as creams, lotions, solutions, or gels. The doctor will consider
the patient's skin type when prescribing a product. Creams and lotions
provide moisture and tend to be good for people with sensitive skin.
Gels and solutions are generally alcohol based and tend to dry the skin.
Therefore, patients with very oily skin or those who live in hot, humid
climates may prefer them. The doctor will tell the patient how to apply
the medicine and how often to use it.
Some people develop side effects from using prescription
topical medicines. Initially, the skin may look worse before improving.
Common side effects include stinging, burning, redness, peeling, scaling,
or discoloration of the skin. With some medicines, like retinoids, these
side effects usually decrease or go away after the medicine is used
for a period of time. Patients should report prolonged or severe side
effects to their doctor. Between 4 and 8 weeks will most likely pass
before patients see their skin improve.
Prescription Oral Medicines
For patients with moderate to severe acne, the doctor
often prescribes oral antibiotics (taken by mouth). Oral antibiotics
are thought to help control acne by curbing the growth of bacteria and
reducing inflammation. Prescription oral and topical medicines may be
combined. For example, benzoyl peroxide may be combined with clindamycin,
erythromycin, or sulfur. Other common antibiotics used to treat acne
are tetracycline, minocycline, and doxycycline. Some people have side
effects when taking these antibiotics, such as an increased tendency
to sunburn, upset stomach, dizziness or lightheadedness, and changes
in skin color. Tetracycline is not given to pregnant women, nor is it
given to children under 8 years of age because it might discolor developing
teeth. Tetracycline and minocycline may also decrease the effectiveness
of birth control pills. Therefore, a backup or another form of birth
control may be needed. Prolonged treatment with oral antibiotics may
be necessary to achieve the desired results.
Treatment for Severe Nodular
or Cystic Acne
People with nodules or cysts should be treated by a dermatologist.
For patients with severe inflammatory acne that does not improve with
medicines such as those described above, a doctor may prescribe isotretinoin
(Accutane*), a retinoid. Isotretinoin is an oral drug that is usually
taken once or twice a day with food for 15 to 20 weeks. It markedly
reduces the size of the oil glands so that much less oil is produced.
As a result, the growth of bacteria is decreased.
* Brand names included in this booklet
are provided as examples only, and their inclusion does not mean that
these products are endorsed by the National Institutes of Health or
any other Government agency. Also, if a particular brand name is not
mentioned, this does not mean or imply that the product is unsatisfactory.
Advantages of Isotretinoin (Accutane)
Isotretinoin is a very effective medicine that can help
prevent scarring. After 15 to 20 weeks of treatment with isotretinoin,
acne completely or almost completely goes away in up to 90 percent of
patients. In those patients where acne recurs after a course of isotretinoin,
the doctor may institute another course of the same treatment or prescribe
other medicines.
Disadvantages of Isotretinoin (Accutane)
Isotretinoin can cause birth defects in the developing
fetus of a pregnant woman. It is important that women of childbearing
age are not pregnant and do not get pregnant while taking this medicine.
Women must use two separate effective forms of birth control at the
same time for 1 month before treatment begins, during the entire course
of treatment, and for 1 full month after stopping the drug. They should
ask their doctor when it is safe to get pregnant after they have stopped
taking Accutane.
Some people with acne become depressed by the changes
in the appearance of their skin. Changes in mental health may be intensified
during treatment or soon after completing a course of medicines like
Accutane. A doctor should be consulted if a person feels unusually sad
or has other symptoms of depression, such as loss of appetite or trouble
concentrating.
Other possible side effects include dry eyes, mouth, lips,
nose, or skin; itching; nosebleeds; muscle aches; sensitivity to the
sun; and, sometimes, poor night vision. More serious side effects include
changes in the blood, such as an increase in triglycerides and cholesterol,
or a change in liver function. To make sure Accutane is stopped if side
effects occur, the doctor monitors blood studies that are done before
treatment is started and periodically during treatment. Side effects
usually go away after the medicine is stopped.
Treatments for Hormonally Influenced
Acne in Women
Clues that help the doctor determine whether acne in an
adult woman is due to an excess of androgen hormones are hirsutism (excessive
growth of hair in unusual places), premenstrual acne flares, irregular
menstrual cycles, and elevated blood levels of certain androgens. The
doctor may prescribe one of several drugs to treat women with this type
of acne. Low-dose estrogen birth control pills help suppress the androgen
produced by the ovaries. Low-dose corticosteroid drugs, such as prednisone
or dexamethasone, may suppress the androgen produced by the adrenal
glands. Finally, the doctor may prescribe an antiandrogen drug, such
as spironolactone (Aldactone). This medicine reduces excessive oil production.
Side effects of antiandrogen drugs may include irregular menstruation,
tender breasts, headache, and fatigue.
Other Treatments for Acne
Doctors may use other types of procedures in addition
to drug therapy to treat patients with acne. For example, the doctor
may remove the patient's comedones during office visits. Sometimes the
doctor will inject cortisone directly into lesions to help reduce the
size and pain of inflamed cysts and nodules.
Early treatment is the best way to prevent acne scars.
Once scarring has occurred, the doctor may suggest a medical or surgical
procedure to help reduce the scars. A superficial laser may be used
to treat irregular scars. Another kind of laser allows energy to go
deeper into the skin and tighten the underlying tissue and plump out
depressed scars. Dermabrasion (or microdermabrasion), which is a form
of "sanding down" scars, is sometimes combined with the subsurface laser
treatment. Another treatment option for deep scars caused by cystic
acne is the transfer of fat from one part of the body to the face.
How Should People With Acne
Care for Their Skin?
Clean Skin Gently
Most doctors recommend that people with acne gently wash
their skin with a mild cleanser, once in the morning and once in the
evening and after heavy exercise. Some people with acne may try to stop
outbreaks and oil production by scrubbing their skin and using strong
detergent soaps and rough scrub pads. However, scrubbing will not improve
acne; in fact, it can make the problem worse. Patients should ask their
doctor or another health professional for advice on the best type of
cleanser to use. Patients should wash their face from under the jaw
to the hairline. It is important that patients thoroughly rinse their
skin after washing it. Astringents are not recommended unless the skin
is very oily, and then they should be used only on oily spots. Doctors
also recommend that patients regularly shampoo their hair. Those with
oily hair may want to shampoo it every day.
Avoid Frequent Handling of the Skin
People who squeeze, pinch, or pick their blemishes risk
developing scars or dark blotches. People should avoid rubbing and touching
their skin lesions.
Shave Carefully
Men who shave and who have acne can test both electric
and safety razors to see which is more comfortable. Men who use a safety
razor should use a sharp blade and soften their beard thoroughly with
soap and water before applying shaving cream. Nicking blemishes can
be avoided by shaving lightly and only when necessary.
Avoid a Sunburn or Suntan
Many of the medicines used to treat acne can make a person
more prone to sunburn. A sunburn that reddens the skin or suntan that
darkens the skin may make blemishes less visible and make the skin feel
drier. However, these benefits are only temporary, and there are known
risks of excessive sun exposure, such as more rapid skin aging and a
risk of developing skin cancer.
Choose Cosmetics Carefully
People being treated for acne often need to change some
of the cosmetics they use. All cosmetics, such as foundation, blush,
eye shadow, and moisturizers, should be oil free. Patients may find
it difficult to apply foundation evenly during the first few weeks of
treatment because the skin may be red or scaly, particularly with the
use of topical tretinoin or benzoyl peroxide. Oily hair products may
eventually spread over the forehead, causing closed comedones. Products
that are labeled as noncomedogenic (do not promote the formation of
closed pores) should be used; in some people, however, even these products
may cause acne.
What Research Is Being Done
on Acne?
Medical researchers are working on new drugs to treat
acne, particularly topical antibiotics to replace some of those in current
use. As with many other types of bacterial infections, doctors are finding
that, over time, the bacteria that are associated with acne are becoming
resistant to treatment with certain antibiotics. Research is also being
conducted by industry on the potential side effects of isotretinoin
and the long-term use of medicines used for treating acne.
Scientists are working on other means of treating acne.
For example, researchers are studying the biology of sebaceous cells
and testing a laser in laboratory animals to treat acne by disrupting
sebaceous glands. Scientists are also studying the treatment of androgenic
disorders, including acne, in men by inhibiting an enzyme that changes
testosterone to a more potent androgen.
Where Can People Find More
Information on Acne?
National Institute of Arthritis and Musculoskeletal
and Skin Diseases (NIAMS)
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301-495-4484 or 877-22-NIAMS (226-4267) (free of charge)
TTY: 301-565-2966
Fax: 301-718-6366
www.niams.nih.gov
NIAMS provides information about various forms of arthritis
and rheumatic disease and bone, muscle, joint, and skin diseases. It
distributes patient and professional education materials and refers
people to other sources of information. Additional information and updates
can also be found on the NIAMS Web site.
American Academy of Dermatology
P.O. Box 4014
Schaumburg, IL 60168-4014
Phone: 847-330-0230 or 888-462-3376 (free of charge)
Fax: 847-330-0050
www.aad.org
This national organization can provide referrals to dermatologists.
It also publishes a brochure on acne for adults and a fact sheet for
young people. These are available on the organization's Web site or
can be obtained by calling or writing to the academy.
Acknowledgments
The NIAMS gratefully acknowledges the assistance of Robert
Katz, M.D., Rockville, MD; Larry Miller, M.D., Chevy Chase, MD; Alan
Moshell, M.D., NIAMS, NIH; Gary Peck, M.D., Washington Hospital Center,
Washington, DC; and Maria Turner, M.D., National Cancer Institute, NIH,
in the preparation and review of this booklet.
The mission of the National Institute of Arthritis and
Musculoskeletal and Skin Diseases (NIAMS), a part of the National Institutes
of Health (NIH), is to support research into the causes, treatment,
and prevention of arthritis and musculoskeletal and skin diseases, the
training of basic and clinical scientists to carry out this research,
and the dissemination of information on research progress in these diseases.
The National Institute of Arthritis and Musculoskeletal and Skin Diseases
Information Clearinghouse is a public service sponsored by the NIAMS
that provides health information and information sources. Additional
information can be found on the NIAMS Web site at www.niams.nih.gov.
This booklet is not copyrighted. Readers are encouraged
to duplicate and distribute as many copies as needed.
Additional copies of this booklet are available from
National Institute of Arthritis and Musculoskeletal
and Skin Diseases (NIAMS) Information Clearinghouse
National Institutes of Health (NIH)
1 AMS Circle
Bethesda, MD 20892-3675
NIH Publication No. 01-4998