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Menopause
Topical Estrogen
By Topical Estrogen
Mar 13, 2003, 10:00pm
Any discussion of estrogen must begin with the controversial,
highly publicized cessation of the estrogen/progestin arm of
the Women's Health Initiative during the summer of 2002. Results
from the halted phase of the National Heart, Lung, and Blood
Institute–sponsored initiative linked the study medication
with an elevated risk of breast cancer, thromboembolic disease,
and cardiovascular disease.
Physicians should note that only this hormone replacement
therapy (HRT) phase was halted; the estrogen replacement therapy
(ERT) phase, showing dissimilar results thus far, continues.
(HRT combines estrogen with progestin and is indicated for
women who have undergone natural menopause; ERT is an estrogen-only
regimen indicated for women whose menopause is surgically induced.)
The basis for topical estrogen study stems from the findings
of a correlation between natural estrogen depletion and chronologic
aging, especially aging of the skin.
Estrogen is a dynamic hormone that is matched with an equally
impressive array of exogenous replacement products. The family
of estrogen products includes estrogens in conjugated or esterified
forms, ethinyl estradiols, estradiols, estradiol derivatives
such as estradiol valerate and estradiol cypionate, estriols,
and estrones.
Effect of estrogen on the skin: Histologic evidence of decreased
skin thickness in postmenopausal women is well known. The epidermis
is thinned, exhibiting a loss of rete ridges. ERT has been
shown to reverses these alterations, buttressing the hypothesis
that it is the lack of estrogen that causes them in the first
place (Maturitas 35[2]:107-17, 2000). In a clinical trial,
Dr. A. Callens evaluated 98 postmenopausal women, comparing
the skin of patients on HRT with the skin of those not receiving
hormone therapy. Patients on HRT exhibited greater skin thickness
as assessed by B-mode ultrasound high-resolution echography
(Dermatology 193[4]:289-94, 1996).
Current theory suggests that skin thickness alterations associated
with aging are due to hormonal effects on collagen (Maturitas
15[2]:113-19, 1992), elastic fibers (Ann. Chir. Gynaecol. Suppl.
202:39-41, 1987), and dermal hyaluronic acid content (J. Invest.
Dermatol. 87[5]:668-73, 1986). By elevating acid mucopolysaccharides
and hyaluronic acid in the skin—and perhaps regulating
the function of the stratum corneum—estrogen has been
shown to maintain skin moisture (Am. J. Clin. Dermatol. 2[3]:143-50,
2001).
The decline in skin collagen that coincides with aging is
known to occur at a greater rate during the first few years
after menopause. One study found that within the first 5 years
after the onset of menopause, roughly 30% of skin collagen
is lost, with an average decline of 2.1% per postmenopausal
year over a period of 20 years (Br. Med. J. [Clin. Res. Ed.]
287[6402]:1337-38, 1983). Patients in this study who were treated
with ERT experienced an increase in skin collagen. In fact,
women on HRT had a skin collagen content 48% higher than those
not on HRT.
Estrogen levels may also be proved to alter glycosaminoglycans
content in the skin.
Wrinkles, vascularization, and hair: Type 1 collagen content,
glycosaminoglycans content, and skin thickness all play a role
in wrinkle formation. It is not surprising then that women
on HRT, which has been demonstrated to affect each of these
factors, would exhibit reduced wrinkling.
A recent study showed that HRT in postmenopausal women limited
the number and depth of wrinkles, measured by optical profilometry
and computerized image analysis (J. Am. Geriatr. Soc. 45[2]:220-22,
1997). Research also shows that topical estradiol (17--estradiol
and 17--estradiol) can promote the development of new connective
repair areas in photodamaged skin as effectively as all-trans-retinoic
acid (Arch. Dermatol. Res. 294[5]:231-36, 2002).
Research has identified both estrogen and androgen receptors
on dermal fibroblasts and epidermal keratinocytes (J. Reprod.
Med. 35[11]:1015-16, 1990). Distribution is inconsistent, with
a preponderance of estrogen receptors located on skin overlying
the female external genitalia, as well as the face, breast,
and thigh. The areas of the epidermis found to be most sensitive
to estrogen are concentrated in the granular layer, although
estrogen-sensitive structures are also present throughout the
epidermis, in hair follicles, and the sebaceous glands (Br.
J. Dermatol. 117[2]:217-24, 1987).
Although the presence of estrogen receptors on the skin is
well established, the mechanism by which estrogen affects the
skin remains unknown. Further, some have speculated that the
epidermis is not a target structure for estrogens under clinical
conditions, despite the abundance of estrogen receptors found
there (Maturitas 11[3]:229-34, 1989).
One potential benefit of estrogen therapy is increased vascularization
of the skin or limiting the devascularization that occurs in
normal aging. Women on HRT have been reported to exhibit a
20%-30% increase in nail capillary blood flow (Maturitas 22[1]:37-46,
1995), compared with those not on hormone replacement. Long-term
estrogen therapy in postmenopausal women has yet to show changes
in resting or maximal skin blood flow, however (J. Appl. Physiol.
85[2]:505-10, 1998).
Estrogen also has been shown to regulate the anagen-telogen
cycle (Proc. Natl. Acad. Sci. USA 93[22]:12,525-30, 1996).
The higher levels of estrogen during pregnancy cause the hair
to grow by increasing the amount of hair in the anagen phase.
The hair loss often seen in postmenopausal women is likely
the result, at least partially, of the increased amount of
hair in the telogen phase.
More research with topical estrogen: Research shows that topical
estrogen acts like oral HRT in preserving skin thickness and
increasing collagen and glycosaminoglycans content of the skin.
Dr. J.B. Schmidt and colleagues examined the effects of topical
0.01% estradiol and 0.3% estriol, and after 6 months of treatment,
the investigators found improvements in skin elasticity, firmness,
and wrinkle depth similar to that seen in studies using oral
or transdermal HRT (Int. J. Dermatol. 35[9]:669-74, 1996).
In light of the observed effects of topical estrogen on skin
thickness and connective tissue, interest emerged on the potential
results for facial skin of topical estrogen administration.
Side effects: Adverse local side effects, such as allergic
contact dermatitis, are seen in about 20% of patients who use
transdermal estradiol (J. Reprod. Med. 47[6]:507-09, 2002).
Patch testing can be used to identify susceptibility. Women
who use topical estrogen and typically have close contact with
children should be aware that gynecomastia, rapid growth, and
advanced bone age can result when prepubescent children are
indirectly exposed to excessive amounts of topical estrogen
(Pediatrics 105[4]:E55, 2000). It should be noted that the
Food and Drug Administration does not regulate custom-compounded
topical estrogen formulations, which can contain high levels
of estrogen.
Products: Although Premarin is better known as an oral ERT,
this product is available as a vaginal cream and has been tested
for facial use. In a randomized, double-blind, parallel group
study, Premarin was found to be significantly more effective
than placebo at enhancing the appearance of fine wrinkles after
12 and 24 weeks. The Premarin group also exhibited significantly
greater skin thickness at week 24 (Maturitas 19[3]:211-23,
1994). A 1-month supply of Premarin cream is available for
$50.
Estrace is the most commonly prescribed oral estradiol. One
milligram of Estrace is comparable to 0.625 mg of Premarin.
Because Estrace can be easily excreted from the system, patients
are often advised to take a half dose by mouth in the morning
and a half dose at night. A 1-month supply of Estrace cream
sells for $42.
Climara is an estradiol patch available at 3.8 mg ($15 per
package of four patches) and 7.6 mg ($22 per package of four
patches). Estraderm is another estradiol patch available in
packets of eight: 0.025 mg ($20), 0.05 mg ($22), and 0.1 mg
($36).
Vivelle-Dot is the smallest transdermal estradiol patch delivery
system. This product is available in dose strengths of 0.025,
0.0375, 0.05, 0.075, and 0.1 mg per day. The smallest dose
strength is indicated only for the prevention of postmenopausal
osteoporosis.
Estrogel became available 4 years ago as the first estrogen
gel to treat natural or surgically induced estrogen deficiency
or menopausal symptoms such as hot flashes, vaginal atrophy,
mood swings, and sleep disturbances. This ERT is a transdermal
preparation combining a hydroalcoholic gel and 0.06% 17--estradiol
derived from yam. Estrogel has a low side effect profile and
is associated with a lower incidence of skin irritation, compared
with transdermal estrogen patches, and has a 20-year track
record of safe, effective use in Europe.
Estrasorb, an estradiol topical emulsion, might be the first
FDA-approved ERT in a topical lotion. Estrasorb (3 g contains
7.5 mg estradiol) incorporates 17--estradiol in a soy-based
oil formulation designed to deliver systemic levels of estrogen
through the skin. A new drug application was withdrawn in April
2002 to address chemistry, manufacturing, and controls questions,
but Estrasorb manufacturer Novavax Inc. resubmitted the new
drug application at the end of October 2002. Estrasorb is intended
for short-term therapy.
There are also several generic forms of estradiol available.
In all cases, they're made from plant sources (phytoestrogens)
and micronized.
With an increasing number of women from the baby boom generation
entering menopause, it is safe to assume that pharmaceutical
manufacturers with an already significant stake in hormone
and estrogen replacement therapies are expanding research efforts
to find safer, more effective estrogen therapies. It is likely
that the positive effects that topical estrogens may confer
on facial skin will achieve greater prominence in the coming
years.
I prescribe topical Estrace for all postmenopausal women not
on HRT who do not have a contraindication. These women usually
report decreased dryness, increased tone, and plumpness of
the skin within 2 weeks. Although this evidence is anecdotal,
I plan to pursue future clinical trials using these topical
estrogens.
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