AcnePage 3 of 4
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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.
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.
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.
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.
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.
* 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.
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.
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