Hi,

I found the article below on Medscape -- it's actually from the
Jan/Feb '05 edition of SkinMed.

Take care,
Matija

Need to register to see it here. Registration is free.
http://www.medscape.com/viewarticle/499712_2


Rosacea in a New Light

Stephen C. Romagnolo, MD; Anthony V. Benedetto, DO

Rosacea is a common skin condition, whose prevalence in the United
States appears to be on the rise.{1,2,3] Even though there are
numerous topical and oral therapies with efficacy in controlling the
papulopustular component of rosacea, their effects on the
telangiectasias, erythema, and flushing associated with rosacea have
been varied and often lacking. Recent studies have shown (by Laser-
Doppler flowmetry) that lesional blood flow in rosacea patients was
three to four times that of control subjects.[4]

Pulsed Dye Lasers for the Treatment of Rosacea
Pulsed dye lasers have been used to treat persistent and recalcitrant
rosacea since the early 1990s.[1] The pulsed dye laser was the first
laser developed based on the theory of selective photothermolysis.[3]
By using the appropriate wavelength of light and pulse duration,
selective coagulation necrosis of the target tissue can be
accomplished, while minimizing damage to surrounding structures and
reducing the risk of scar formation. The pulsed dye laser can be used
to treat rosacea because it selectively targets the hemoglobin within
the increased vascular structures seen in rosacea and eliminates
them. The prototype pulsed dye laser—the flash lamp-pumped pulsed dye
laser—was specifically developed for the treatment of cutaneous
vascular lesions such as port wine stains and hemangiomas. This
initial model had a wavelength of 577 nm, which corresponded to the
third absorption peak of oxyhemoglobin. The wavelength was then
adjusted to 585 nm, which provided for greater depth of dermal
penetration without loss of vascular specificity. A pulse duration of
1–5 milliseconds is the range of thermal relaxation time of small-to-
medium blood vessels. Thus the heat produced by each laser pulse is
confined to the targeted blood vessels and is dissipated before it
can diffuse to adjacent normal structures, thereby minimizing
scarring.[1] The fact that many patients with rosacea did not obtain
satisfactory results indicated that this older model of pulsed dye
laser might not have been ideal for clearing the telangiectatic mats
and angiomas of rosacea. This is likely due to the fact that many of
the vessels were too large and too deep for the available wavelength
(585 nm) and pulse duration (0.45 milliseconds) of this laser.

Recent improvements in the pulsed dye laser have included a longer
wavelength to enable deeper penetration, a longer pulse width to
enable destruction of larger vessels, and the attachment of a dynamic
cooling device to the laser tip to decrease the pain of the procedure
and the potential for epidermal scalding. This conveniently allows
for the safe use of higher available fluences.[5] These long-pulsed
lasers, emitting light at 590–600 nm with pulse durations ranging
from 1 to 10 milliseconds, can be used to treat large-caliber and
deep dermal blood vessels.[6] The vessels associated with rosacea are
of the size, and are usually located within depths that are suitable
for the selective targeting by these long-pulsed tunable dye lasers.


Intense Pulsed Light for Treatment of Rosacea
Intense Pulsed Light (IPL) systems are a relatively new addition to
the list of available treatments for rosacea. These systems utilize
high intensity pulsed light sources that emit noncoherent,
polychromatic light from 515– 1200 nm. The mechanism of action of IPL
systems is that of selective photothermolysis described by Anderson
and Parrish.[7] By utilizing knowledge of the absorption coefficients
for the main chromophores in the skin, one can effectively choose the
wavelength(s) of light that would most selectively destroy the target
of interest while sparing surrounding tissue. For instance,
hemoglobin absorbs primarily at a wavelength of 580 nm, whereas
melanin takes in the entire visible spectral range

When using IPL systems one chooses cutoff filters (515–755 nm) which
filter out the spectrum of light of wavelengths less than the number
designated on the filter. As with laser systems, longer wavelengths
in the visible spectral range penetrate more deeply. Choice of an
appropriate cut-off filter should be guided by the absorption spectra
of the target and surrounding tissue, as well as the depth of the
target of interest.[8] Keeping the pulse duration (generally between
0.5–88.5 milliseconds) lower than the thermal relaxation time of the
target structures may spare the surrounding tissue from excess
heating.[8,9,10] When treating larger target vessels, a high fluence
may be split into multiple pulses with intervening delays of between
1–300 milliseconds. The delay allows the nontarget tissues to cool
down between pulses while the heat is retained in the target of
interest.[9]

The nonfixed wavelengths in IPL systems, ranging from visible to
infrared, may offer the advantage of treating telangiectasias at
different dermal depths since longer wavelengths penetrate more
deeply.[11] In addition, the larger spot size with IPL may make it
simpler to treat an entire face.[12] A recent study evaluating the
efficacy of intense pulse light treatment on rosacea patients found
that 83% of patients had reduced redness, 75% noted reduced flushing
and improved skin texture, and 64% noted fewer acneiform breakouts.
[12] Treatments were given with the Vasculite Plus IPL system
(Lumenis Inc., Santa Clara, CA) at 2.4/4.0 milliseconds double pulse
with a 20 milliseconds delay time. Fluences varied from 32–36 J/cm2
when a 570 nm filter was used or 27–32 J/cm2 with a 560 nm filter.
Patients received treatments at 3-week intervals, with an average of
3.6 treatments and average follow up of 3.7 months. In another small
series, treatment of rosacea patients with a Photoderm VL (Lumenis
Inc., Santa Clara, CA) system resulted in a statistically significant
decrease in blood flow in the treated area, decrease in actual area
of the cheek occupied by telangiectasia, and decrease in the
intensity of erythema.[13] Each patient was treated five times at 3-
week intervals with the Photoderm VL using a 515 nm filter, single-
pulse duration of 3 milliseconds, and various fluences. Assessments
were made at baseline and 1 month after the last treatment.

Work that remains to be done in optimizing the use of pulsed dye
lasers and IPL systems in the treatment of rosacea includes
clarifying treatment parameters, the effect of treatment frequency,
and the utility of adjuvant light-based therapies. Moreover, larger
studies are needed in assessing the effect of light-based treatments
on the papulopustular component of rosacea.

Stephen C. Romagnolo, MD,1 and Anthony V. Benedetto, DO1,2 ,
University of Pennsylvania School of Medicine, Philadelphia, PA,1 and
The John Hopkins School of Medicine, Baltimore, MD2