Acne
Contents
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.
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Normal Pilosebaceous Unit |
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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.
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.
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.
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.
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.
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.
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.
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