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Leejiham Skin Clinic and Department of Dermatology, Yonsei University College of Medicine, Seoul, Korea. BACKGROUND:
Acne scarring is a common complication of acne and yet no appropriate
and effective single treatment modality has been developed. We suggest
a technique consisting of the focal application of higher
trichloroacetic acid (TCA) concentrations by pressing hard on the
entire depressed area of atrophic acne scars. This technique is called
chemical reconstruction of skin scars (CROSS) by the authors.
OBJECTIVE: To evaluate the clinical effects of CROSS on atrophic acne
scars in dark-complexioned patients. METHODS: An analysis was conducted
of 65 patients with atrophic acne scars who were treated with CROSS in
our hospitals between July 1996 and July 2001. Thirty-three patients
were treated with 65% TCA CROSS and 32 patients were treated with 100%
TCA CROSS. All patients had Fitzpatrick skin types IV-V. RESULTS:
Patient treatment data indicated that 27 of 33 patients (82%) (the 65%
TCA group) and 30 of 32 patients (94%) (the 100% TCA group) experienced
a good clinical response. All patients in the 100% TCA group who
received five or six courses of treatment showed excellent results.
Good satisfaction rates in the 65% and 100% TCA groups were recorded.
There were no cases of significant complication. CONCLUSION: CROSS is a
safe and very effective single modality for the treatment of atrophic
acne scars with no significant complications.
Acne
Scarring
A detailed and comprehensive discussion
of acne scars starts with causes of scarring, prevention of
scarring, types of scars, and treatments for scars.
Before talking about scars, a word
about spots that may look like scars but are not scars in the sense
that a permanent change has occurred. Even though they are not true
scars and disappear in time, they are visible and can cause
embarrassment.
Macules
or "pseudo-scars" are flat, red or reddish spots that are the final
stage of most inflamed acne lesions. After an inflamed acne lesion
flattens, a macule may remain to "mark the spot" for up to 6 months.
When the macule eventually disappears, no trace of it will
remain—unlike a scar.
Post-inflammatory pigmentation
is discoloration of the skin at the site of a healed or healing
inflamed acne lesion. It occurs more frequently in darker-skinned
people, but occasionally is seen in people with white skin. Early
treatment by a dermatologist may minimize the development of
post-inflammatory pigmentation. Some post-inflammatory pigmentation
may persist for up to 18 months, especially with excessive sun
exposure. Chemical peeling may hasten the disappearance of
post-inflammatory pigmentation.
Causes of Acne Scars
In the simplest terms, scars form at
the site of an injury to tissue. They are the visible reminders of
injury and tissue repair. In the case of acne, the injury is caused
by the body’s inflammatory response to sebum, bacteria and
dead cells in the plugged sebaceous
follicle. Two types of true scars exist, as discussed later:
(1) depressed areas such as ice-pick scars, and (2) raised thickened
tissue such as keloids.
When tissue suffers an injury, the body
rushes its repair kit to the injury site. Among the elements of the
repair kit are white blood cells and an array of inflammatory
molecules that have the task of repairing tissue and fighting
infection. However, when their job is done they may leave a somewhat
messy repair site in the form of fibrous scar tissue, or eroded
tissue.
White blood cells and inflammatory
molecules may remain at the site of an active acne lesion for days
or even weeks. In people who are susceptible to scarring, the result
may be an acne scar. The occurrence and incidence of scarring is
still not well understood, however. There is considerable variation
in scarring between one person and another, indicating that some
people are more prone to scarring than others. Scarring frequently
results from severe inflammatory nodulocystic acne
that occurs deep in the skin. But, scarring also may arise from more
superficial inflamed lesions. Nodulocystic acne that is most likely
to result in scars is seen in these photos:
(Photos used with permission of the
American Academy of Dermatology
National Library of Dermatologic Teaching Slides)
The life history of scars also is not
well understood. Some people bear their acne scars for a lifetime
with little change in the scars, but in other people the skin
undergoes some degree of remodeling and acne scars diminish in size.
People also have differing feelings
about acne scars. Scars of more or less the same size that may be
psychologically distressing to one person may be accepted by another
person as "not too bad." The person who is distressed by scars is
more likely to seek treatment to moderate or remove the scars.
Prevention of Acne Scars
As discussed in the previous section on
Causes of Acne Scars, the occurrence of scarring is different in
different people. It is difficult to predict who will scar, how
extensive or deep scars will be, and how long scars will persist. It
is also difficult to predict how successfully scars can be prevented
by effective acne treatment.
Nevertheless, the only sure method of
preventing or limiting the extent of scars is to treat acne early in
its course, and as long as necessary. The more that inflammation can
be prevented or moderated, the more likely it is that scars can be
prevented. (Click on Acne
Treatments for more information about treatment of mild,
moderate and severe acne). Any person with acne who has a known
tendency to scar should be under the care of a dermatologist. (Click
on
Find a
Dermatologist to locate a dermatologist in your geographic
area).
Types of Acne Scars
There are two general types of acne
scars, defined by tissue response to inflammation: (1) scars caused
by increased tissue formation, and (2) scars caused by loss of
tissue.
Scars Caused by Increased Tissue
Formation
The scars caused by increased tissue
formation are called keloids or hypertrophic scars. The word
hypertrophy means "enlargement" or "overgrowth." Both hypertrophic
and keloid scars are associated with excessive amounts of the cell
substance collagen. Overproduction of collagen is a response of skin
cells to injury. The excess collagen becomes piled up in fibrous
masses, resulting in a characteristic firm, smooth, usually
irregularly-shaped scar. The photo shows a typical severe acne
keloid:
(Photo used with permission of the
American Academy of Dermatology
National Library of Dermatologic Teaching Slides)
The typical keloid or hypertrophic scar
is 1 to 2 millimeters in diameter, but some may be 1 centimeter or
larger. Keloid scars tend to "run in families"—that is, abnormal
growth of scar tissue is more likely to occur in susceptible people,
who often are people with relatives who have similar types of scars.
Hypertrophic and keloid scars persist
for years, but may diminish in size over time.
Scars Caused by Loss of Tissue
Acne scars associated with loss of
tissue—similar to scars that result from chicken pox—are more common
than keloids and hypertrophic scars. Scars associated with loss of
tissue are:
Ice-pick scars
usually occur on the cheek. They are usually small, with a
somewhat jagged edge and steep sides—like wounds from an ice pick.
Ice-pick scars may be shallow or deep, and may be hard or soft to
the touch. Soft scars can be improved by stretching the skin; hard
ice-pick scars cannot be stretched out.
Depressed fibrotic scars
are usually quite large, with sharp edges and steep sides. The
base of these scars is firm to the touch. Ice-pick scars may
evolve into depressed fibrotic scars over time.
Soft scars, superficial or deep
are soft to the touch. They have gently sloping rolled edges that
merge with normal skin. They are usually small, and either
circular or linear in shape.
Atrophic macules
are usually fairly small when they occur on the face, but may be a
centimeter or larger on the body. They are soft, often with a
slightly wrinkled base, and may be bluish in appearance due to
blood vessels lying just under the scar. Over time, these scars
change from bluish to ivory white in color in white-skinned
people, and become much less obvious.
Follicular macular atrophy
is more likely to occur on the chest or back of a person with
acne. These are small, white, soft lesions, often barely raised
above the surface of the skin—somewhat like
whiteheads
that didn’t fully develop. This condition is sometimes also called
"perifollicular elastolysis." The lesions may persist for months
to years.
Treatments for Acne Scars
A number of treatments are available
for acne scars through dermatologic
surgery. The type of treatment selected should be the one
that is best for you in terms of your type of skin, the cost, what
you want the treatment to accomplish, and the possibility that some
types of treatment may result in more scarring if you are very
susceptible to scar formation.
A decision to seek dermatologic
surgical treatment for acne scars also depends on:
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The way you feel about scars. Do acne
scars psychologically or emotionally affect your life? Are you
willing to "live with your scars" and wait for them to fade over
time? These are personal decisions only you can make.
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The severity of your scars. Is
scarring substantially disfiguring, even by objective assessment?
Before committing to treatment of acne
scars, you should have a frank discussion with your dermatologist
regarding those questions, and any others you feel are important.
You need to tell the dermatologist how you feel about your scars.
The dermatologist needs to conduct a full examination and determine
whether treatment can, or should, be undertaken.
The objective of scar treatment is to
give the skin a more acceptable physical appearance. Total
restoration of the skin, to the way it looked before you had acne,
is often not possible, but scar treatment does usually improve the
appearance of your skin.
The scar treatments that are currently
available include:
Collagen injection.
Collagen, a normal substance of the body, is injected under the
skin to "stretch" and "fill out" certain types of superficial and
deep soft scars. Collagen treatment usually does not work as well
for ice-pick scars and keloids. Collagen derived from cows or
other non-human sources cannot be used in people with autoimmune
diseases. Human collagen or fascia is helpful for those allergic
to cow-derived collagen. Cosmetic benefit from collagen injection
usually lasts 3 to 6 months. Additional collagen injections to
maintain the cosmetic benefit are done at additional cost.
Autologous fat transfer.
Fat is taken from another site on your own body and prepared for
injection into your skin. The fat is injected beneath the surface
of the skin to elevate depressed scars. This method of autologous
(from your own body) fat transfer is usually used to correct deep
contour defects caused by scarring from nodulocystic acne. Because
the fat is reabsorbed into the skin over a period of 6 to 18
months, the procedure usually must be repeated. Longer lasting
results may be achieved with multiple fat-transfer procedures.
Dermabrasion.
This is thought to be the most effective treatment for acne scars.
Under local anesthetic, a high-speed brush or fraise used to
remove surface skin and alter the contour of scars. Superficial
scars may be removed altogether, and deeper scars may be reduced
in depth. Dermabrasion does not work for all kinds of scars; for
example, it may make ice-pick scars more noticeable if the scars
are wider under the skin than at the surface. In darker-skinned
people, dermabrasion may cause changes in pigmentation that
require additional treatment.
Microdermabrasion.
This new technique is a surface form of dermabrasion. Rather than
a high-speed brush, microdermabrasion uses aluminum oxide crystals
passing through a vacuum tube to remove surface skin. Only the
very surface cells of the skin are removed, so no additional wound
is created. Multiple procedures are often required but scars may
not be significantly improved.
Laser Treatment.
Lasers of various wavelength and intensity may be used to
recontour scar tissue and reduce the redness of skin around healed
acne lesions. The type of laser used is determined by the results
that the laser treatment aims to accomplish. Tissue may actually
be removed with more powerful instruments such as the carbon
dioxide laser. In some cases, a single treatment is all that will
be necessary to achieve permanent results. Because the skin
absorbs powerful bursts of energy from the laser, there may be
post-treatment redness for several months.
Skin Surgery.
Some ice-pick scars may be removed by "punch" excision of each
individual scar. In this procedure each scar is excised down to
the layer of subcutaneous fat; the resulting hole in the skin may
be repaired with sutures or with a small skin graft. Subcision
is a technique in which a surgical probe is used to lift the scar
tissue away from unscarred skin, thus elevating a depressed scar.
Skin grafting may be necessary
under certain conditions—for example, sometimes dermabrasion
unroofs massive and extensive tunnels (also called sinus tracts)
caused by inflammatory reaction to sebum and bacteria in sebaceous
follicles. Skin grafting may be needed to close the defect of the
unroofed sinus tracts.
Treatment of keloids.
Surgical removal is seldom if ever used to treat keloids. A person
whose skin has a tendency to form keloids from acne damage may
also form keloids in response to skin surgery. Sometimes keloids
are treated by injecting steroid drugs into the skin around the
keloid. Topical retinoic acid may be applied directly on the
keloid. In some cases the best treatment for keloids in a highly
susceptible person is no treatment at all.
In summary, acne scars are caused by
the body’s inflammatory response to acne lesions. The best way to
prevent scars is to treat acne early, and as long as necessary. If
scars form, a number of effective treatments are available.
Dermatologic surgery treatments should be discussed with a
dermatologist.
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