Laser hair removal in Asian skin
Three studies evaluated the effect and results of Alexandrite
laser hair removal on darker Asian skin types. This hair removal
was successful on lighter skin. Doctors used one, two or three
treatments on the study groups. They evaluated effectiveness of
multiple treatments and if they cause skin problems for the study
groups. They determined the benefits of test patches before treatments.
One hundred forty four people were in the study. They each people
had Type III, IV or V Fitzpatrick skin types. Cooled laser fluences
of 16 to 24 J/cm squared were used. A test patch was done before
the treatments began. Participants were divided into three groups.
Group A contained 35 people with 66 sites, and received three
treatments. Group B contained 35 people with 66 sites, and were
given two treatments. Group C contained 74 people with 124 sites,
and had one treatment. Their evaluation covered nine months.
Each group was checked for significant hair reduction nine months
after their final treatment. Group A experienced 55% reduction
of hair, Group B had 44% reduction and Group C had 32% reduction.
The researchers checked for scarring and long term changes to
skin pigmentation, but they found none. Researchers concluded
Asian skin responds well overall to Alexandrite laser treatments,
although there are some temporary complications.
The Study
Familiar hair removal methods include: shaving, waxing, tweezing,
depilation and electrolysis. These methods provide temporary hair
removal. Laser hair removal is an option being tested with various
laser wavelengths. Wavelength changes and different number of
treatments, give varying results.
This study will evaluate complications associated with laser
skin removal on darker skin. Researchers want to identify the
effects of this treatment and what complications are experienced.
It would determine if there was any relevance between use of test
patches and future complications. The final reason was to determine
whether additional treatments were more effective.
The Methods
Healthy Asians from 18-48 were involved. 144 people participated.
The researchers eliminated participants who “were pregnant,
had infections, systemic diseases or a history of skin problems”.
An alexandrite hair removal laser was used. “This laser
emits a 755 nm laser with irradiation through a lens-coupled optical
fiber”. During these treatments, cold air cooling is used
to cool the skin. The temperature can be -30 degrees with a flow
of 500-1000 Liters per minute.
The study subjects had 256 areas which needed to be treated.
2cm x 2cm test patches were done beside the affected areas, 72
hours before the treatments began. The fluency was determined
based on each skin type and the site to be treated.
Researchers took digital pictures before treatment and when treatment
finished. They also counted the number of hairs in each location
before treatment and after completion. Hairs were counted by hand
and figured digitally.
Before treatments began, the areas were treated with hydroquinones
or glycolic acid, shaved and cleaned. The “laser parameters
included a fluence of 16 to 24J/cm squared, 40-ms pulse duration
and 12.5 mm diameter spots”. Each parameter was determined
by the test patch results. These patches gave indications of skin
problems, such as: crusting, whitening, blistering and so on.
After the tests, the researchers picked the highest fluence that
was safe.
The study subjects were instructed to use sun screen during the
study. They would have the treatments, and then checked for complications.
The schedule would be “after 24 hours, 1 week, 1 month,
2 months, 3 months, 6 months and finally at 9 months after the
treatment was completed”. Any complications were documented
through notes and photographs.
The Results –
The results varied between the groups. However, the group with
three treatments had greater hair reduction. Group A had a 77%
reduction three months after the treatments ended and 55%, 9 months
after treatment. Group B had 62% reduction at 3 months after two
treatments and 44%, 9 months after their final treatment. Group
C had the least reduction with 44% after three months and 32%,
9 months after their initial treatment.
No important difference was noticed in effects to the skin types.
There were minimal short term side effects. They didn’t
note scarring or long term changes to the skin. Researchers knew
that darker skin types usually had short term side effects, but
not all study subjects had problems.
Most complications disappeared within 9-14 days. One subject
had severe crusting, which was gone within four weeks. Another
subject had widespread folliculitis on her legs, which began two
weeks after her treatments, but was gone within ten weeks. The
researchers did not find any connection between the test patches
and later results.
The Discussion –
Even though this process is accepted, questions remain. Are the
effects dictated by the number of treatments? Is this treatment
(755 nm wavelength) safe for Asian skin? Were the reactions to
the test patches indicative of later complications?
Other studies were done, but there were too many differences
to compare them. The wavelengths used in this study were based
on reactions on the test patches. However, they believe increased
sun exposure before the treatments could lead to complications.
Minor complications were experienced and most passed quickly
with no permanent difficulties. A stronger fluence could cause
damage to Asian skin. Keeping the skin cool during the treatments
limits the possible problems.
The researchers waited nine months to verify if treatment results
were permanent. Additional treatments provided better results.
The Conclusion –
The researchers found that caution must be exercised when using
laser hair removal techniques on individuals with Asian skin.
Their results show that a 755nm alexandrite laser with longer
pulse duration should be used. More hair can be removed if the
doctor uses a higher pulse, but that brings a higher chance of
complications. As mentioned earlier, there is no connection between
the test patches and final results. Another study could test the
time between test patches and the actual treatments are done.
This change could produce different conclusions
Laser
hair removal in Asian skin references
- Hussain M, Polnikorn N, Goldberg DJ. Laser-assisted
hair removal in Asian skin: efficacy, complications, and the
effect of single versus multiple treatments.
Dermatol Surg. 2003 Mar;29(3):249-54.
PMID: 12614418
- Chan HH, Alam M, Kono T, Dover JS. Clinical application of
lasers in Asians. Dermatol Surg. 2002 Jul;28(7):556-63.
PMID: 12135505
- Hussain M, Suwanchinda A, Charuwichtratana S, Goldberg D.
A new long pulsed 940 nm diode laser
used for hair removal in Asian skin types. J Cosmet Laser Ther.
2003 Jun;5(2):97-100.
PMID: 12850801
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