The precise etiology of striae distensae (SD) remains to
be elucidated. Obesity and rapid weight gain or weight
loss have been shown to be associated with the formation
of SD.1 While many believe that mechanical stretching of
connective tissue, causing it to rupture, is the main cause, others
suggest that normal growth, associated with high serum
levels of steroid hormones may be the cause.2 Elevated serum
levels of steroid hormones have a catabolic effect on the fibroblast
activity, causing a decrease in deposits of collagen in the
substance of the dermal matrix. High risk groups include adolescents
and pregnant women who experience a rapid increase
in size of particular regions of the body. SD are two and a half
times more frequent in women, compared to men. In boys, the
outer aspects of the thighs and the lumbosacral region are the
most common sites; in girls, the thighs, upper arms, buttocks
and breasts are the most common.3
Early SD are pinkish red, so-called striae rubra (SR), and may be
slightly raised. They typically become darker purple in color, but
eventually become white and slightly atrophic, so-called striae
alba (SA). Histologically, SD are indistinguishable from scars.
Collagen bands in the upper reticular dermis are stretched and
are aligned parallel to the surface of the skin. There is overall
loss of collagen and elastin, with flattening of the rete ridges.4
SD are most likely to respond to therapy in the earliest stages
(SR). Once they become mature and whitened (SA), they are
very difficult to eradicate. Treatment consists of various topical
therapies, as well as lasers and light devices, RF devices, microdermabrasion
and needling.
Topical Therapy
Tretinoin has been shown to clinically improve the appearance
of early SR without much effect on mature SA. In one
study, 22 patients applied 0.1% tretinoin (n=10) or a placebo
(n=12) daily for 6 months. Targeted striae in the group treated
with tretinoin decreased in mean length by 14%; and mean
width by 8%, compared with an increase of 10% and 24% in
mean length and width, respectively, in patients who received
the placebo.5 In another study, Rangel et al treated pregnancyrelated
striae of the abdomen in 20 women post-partum. After
0.1% tretinoin cream was applied daily for 3 months, target
lesions decreased by 20%.6
Use of other retinoids, such as tazarotene or adapalene also
may be useful. However, no topical retinoid should be used in
pregnant or breast-feeding females due to possible absorption
and teratogenic effects.7
While there are no well-controlled published studies, glycolic
acid, an AHA, has been known to stimulate collagen production
by fibroblasts and it has been used with varying degrees of success
in treating striae.8
Trichloroacetic acid (TCA 10-35%) has also been used to treat
striae. While there is a lack of published data, many anecdotal
results reveal improvement in color and texture of striae when
a low concentration of TCA is applied at monthly intervals.9
Microdermabrasion
Microdermabrasion has been used to treat acne scars, fine
wrinkles and mottled pigmentation.10 Applied to the stratum corneum,
microdermabrasion appears to induce epidermal signal
transduction pathways that set in motion a cascade of molecular
events, capable of causing remodeling and repair.11 In an Egyptian
study, 20 patients with SD received 5 microdermabrasion
treatments at weekly intervals on half the body; the SD on the
other half of the body served as a control. There was an overall
good-to-excellent response in over half the subjects; upregulation
of type I precollagen MRNA was found in all treated SD
samples.12 Improvement was greater in lesions of SR than SA.
Lasers and Light Devices
The 585nm flashlamp pulsed dye laser (PDL) at low energy
densities is commonly used to target the dilated blood vessels
of SR. A series of treatments at 4-to-6-week intervals has
been purported to increase the amount of collagen in the extracellular
matrix.13,14 The PDL has a moderate, beneficial effect
in reducing the degree of erythema in SR, but no apparent
benefit in SA. Because of the potential for adverse effects,
PDL should be performed with extreme caution or not at all in
Fitzpatrick V-VI patients.
