Acne
vulgaris is the most common skin disorder affecting humans. Nearly
4 out of 5 young adults face this problem at sometime during their
lives. While for many, the disease is simply a nuisance and personal
embarrassment, for others it can be a permanent and disfiguring ailment
resulting in isolation and having a tremendous impact on personal
and social development. While there are many products and therapies
available to treat or prevent acne, the key is in understanding the
multiple processes that lead to the development of the disease and
knowing how to go about preventing the process.
Acne
typically begins in the early teen and preteen years. It is in the
pre-pubertal period that the small glands located on top of both kidneys,
called the adrenals, begin releasing increasing amounts of the hormone
androgen. Androgen in turn stimulates the glands at the base of hair
follicles, principally on the face and trunk, known as sebaceous glands,
to secrete an oily substance known as sebum. While this is a natural
and appropriate response to androgen, most individuals who suffer
from acne have an increased sensitivity to androgen stimulation leading
to increased sebum production. This process alone does not lead to
acne, however. In addition to increased sebum production, the blocking
of the follicles by dead skin cells, which occurs through the process
of desquamation, traps the sebum in the follicle and leads to the
formation of a micro comedo or comedo, which is often noticed by the
individual as either a blackhead (if the comedo is open) or a whitehead
(if the comedo is closed). Finally, a bacteria known as Propionibacterium
acnes, grows inside of the hair follicle, living off of the trapped
sebum. It is this three step process; increased sebum production,
blocking of the hair follicles and bacterial infection, that leads
to the formation of acne vulgaris. In addition it provides the basis
for therapies aimed at clearing up the acne prone skin.
The first target for treatment is the elimination of the bacteria
that live in the hair follicles themselves. Most commonly used are
over-the-counter preparations of Benzoyl peroxide in 1,2.5,5
and 10 % solutions. Benzoyl peroxide easily enters the hair
follicle and kills the bacteria, which is found there. In addition,
topical antibiotics can be used to suppress bacterial growth. The
most commonly used formulations are erythromycin, metronidazole and
clindamycin. The advantage of the antibiotic formulations over benzoyl
peroxide is that they also prevent the formation of inflammatory
mediators produced due to the bacteria, which were not killed by the
antibiotic. Using any of the above treatments once or twice a day
can effectively treat most minor acne. However some individuals with
moderate acne will benefit from an antibiotic taken orally for four
to six weeks until a particularly severe outbreak is under control.
The most commonly used oral antibiotics include tetracycline, minocycline,
doxycycline, clindamycin, tetracycline and trimethoprim-sulfamethoxazole.
These can usually be taken on a once daily regimen.
The second strategy for treating acne involves decreasing the number
of epithelial (skin cells) that clog hair follicles. At present there
are three medications used to slow the sloughing of epithelial cells.
These include tretinoin, isotretinoin and salicylic acid.
Salicylic acid is available as an over-the-counter medication
and sold in 0.5 and 2 percent formulations. Tretinoin is available
by prescription only and is available in 0.025, 0.05 and 0.1 percent
creams and a 0.01 or 0.025 percent gel. These therapies are often
very irritating to the skin and must be used with caution, starting
with the lowest strength and increasing as tolerated. In addition
these products are reserved for moderate to moderate-severe acne and
are often used in combination with systemic antibiotics.
The final mechanism of acne formation is the production of sebum as
described above. Sebum can be removed by washing the face with soap,
however this in no way effects the formation of sebum. In addition,
continued washing and facial scrubbing can lead to local irritation
of the skin and actually worsen the skin's appearance. There is one
prescription medication that can decrease the production of sebum
named isotretinoin. This medication is taken orally and often has
dramatic effects on clearing up acne. It is, however, reserved only
for the most severe form of acne known as cystic acne due to the drugs
side effects, which include elevated lipids, arthralgias, and tendinitis.
In addition the medication is toxic to the fetus requiring all women
on the medication to take some form of birth control.
Another method of decreasing sebum production is with estrogens. Estrogen
itself will decrease the production of sebum, however the doses required
are usually higher then those found in modern birth control. If taken
over several months some women do notice an improvement in their acne,
but this is not an indication for starting birth control.
In conclusion, there are three processes to the formation of acne,
including increased sebum production, blocking of hair follicles by
skin cells and bacterial infection of the hair follicle. Most individuals
with acne can easily treat their symptoms with over-the-counter benzoyl
peroxide. Those with more severe acne may want to see their doctor
and start a prescription antibiotic either topically or orally. A
medication such as tretinoin may be added to the antibiotic
to achieve the desired result. Finally, those with a severe form of
acne known as cystic acne may benefit from oral isotretinoin,
given under close observation of a physician who follows-up on appropriate
lab values.
While acne is a benign disease, it is a condition that may be very
stressful to some. There are many treatments available both over-the-counter
and by prescription that may be used to fight this frustrating condition.
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