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Minoxidil
for alopecia areata
Alopecia areata is a non-scarring, recurrent hair disorder occurring
in 1 to 2% of the population and affecting both sexes in all racial
groups. There is no cure for this mysterious form of hair loss,
and the key challenge of managing alopecia areata lies in finding
a treatment regimen that really works. Most treatment measures
adopted for alopecia areata are immunomodulatory in nature, (i.e.
drugs that change the disordered immune process and have a corrective
effect on the immune system), with corticosteroids the mainstay
of treatment approach. There are also treatment measures available
to help promote hair growth or hide hair loss, which have a direct
action on the hair follicle.
Minoxidil is believed to directly act on hair follicles, promoting
fiber development. Minoxidil is in the class of treatments called "potassium
channel openers" that are used primarily for treating hypertension.
Although several potassium-channel openers have been used in research
for many years, minoxidil is the only approved one in this category
of drugs for use in treating hypertension in humans. Its true
method of action in averting hair loss is not completely understood.
However, it has been clinically proven that drugs that open potassium
channels seem to stimulate hair growth. The use of this drug is
still under experimental refinement for use in alopecia areata.
The medication was originally invented to treat high blood pressure.
The hair growth was seen as a side effect of the medication, and
now it is widely used as a topical solution to treat male pattern
baldness. Minoxidil is now available in two forms to treat different
conditions. Oral minoxidil is used to treat high blood pressure
and the topical solution form is used to treat hair loss and baldness.
Minoxidil for hair loss is a topically applied liquid usually
found in pre-mixed solutions. Minoxidil is an ingredient, which
acts by stimulating hair follicles into growth. Available as an
over the counter treatment, minoxidil does not require a prescription
in 2 percent and 5 percent solutions. The 5 percent solution is
not recommended for use in women because of possible increased
hair growth on the sides of the face. Ideally, topical minoxidil
is applied twice daily to the scalp. Studies indicate that it
may help to grow hair in 10% to 20% of those who use it and it
may slow the rate of the hair loss for 90%. It is usually more
effective for those whose onset of hair loss is recent.
How
does minoxidil work?
Although the exact mechanism of action of minoxidil remains unclear,
the drug is believed to have a direct effect on hair follicles
promoting fiber development. Minoxidil does not appear to have
either a hormonal or an immunosuppressant effect, but most likely
has a direct mitogenic (agent that indices cell division) effect
on epidermal cells.
It is purported that:
- Minoxidil has a well-recognized effect on the prolongation
of keratinocyte (the keratinocyte is the building block of the
epidermis and hair fiber) growth and on increasing the proportion
of hairs in anagen in monkeys and humans with androgenetic alopecia.
- Experiments also show that minoxidil appears to prolong the
survival time of keratinocytes in vitro.
- Minoxidil may oppose intracellular calcium entry. Calcium
influx normally enhances epidermal growth factors to inhibit
hair growth. Minoxidil is converted to minoxidil sulfate, which
is a potassium channel agonist and enhances potassium ion permeability,
thus opposing the entry of calcium into cells.
- Since it was originally a blood-pressure drug it was thought
that minoxidil worked by increasing the amount of blood supply
to the hair follicles. However, other vasodilators do not stimulate
the same response, so it is evident that local vasodilatation
(dilation of blood vessels) does not appear to play a primary
role in hair growth associated with minoxidil.
Minoxidil is believed to have a direct effect on hair follicles
promoting fiber development. It can directly promote hair growth
in androgenetic alopecia. Minoxidil is most often used to treat
alopecia areata by using it in conjunction with other treatments
such as corticosteroids or contact sensitizers. Such combination
treatments are believed to be more effective than using just one
or other treatment alone.
Success
rate of minoxidil in the treatment of alopecia areata
As of now, the results obtained from clinical trials using a
2% concentration are mixed with success rates ranging from 8%
- to 45% in patients with patchy alopecia areata, and no significant
re-growth apparent in patients with extensive alopecia areata.
However, there are reports that suggest a 5% minoxidil solution
elicits a better response rate than the 2% solution. While some
dermatologists are quite enthusiastic in their recommendation
of minoxidil for alopecia areata, others do not regard it as an
effective treatment. Initial re-growth can be seen within 12 weeks,
but continued application is needed to achieve cosmetically acceptable
re-growth. Studies indicate that minoxidil usually is well tolerated.
However, in the treatment of alopecia areata, minoxidil is primarily
used to stimulate hair growth and it does not succeed in stopping
the causes of hair loss - only to prevail over them. Minoxidil
is most often used to treat alopecia areata by using it in conjunction
with other treatments such as corticosteroids or contact sensitizers.
Such combination treatments are believed to be more effective
than using just one or other treatment alone.
Following are some advantages of opting for minoxidil for stimulating
hair re-growth:
- It is available without a prescription
- As it is applied topically, there is less chances of systemic
side effects
- It is safe to use both in men and women
Topical minoxidil is not normally effective in individuals with
100% scalp loss, as seen in alopecia totalis and alopecia universalis.
Even in alopecia areata, topical minoxidil acts as a temporary
measure bridging the gap until hair start growing again on its
own. It is important to remember that minoxidil is a treatment,
not a cure. Sustained progress is only possible by using minoxidil
continuously over the long term to oppose the hair loss. Lapses
in therapy or discontinuation in therapy can cause follicles artificially
kept in the growth phase to enter the resting phase.
Topical anthralin (an irritant that can induce hair growth) and
minoxidil used together appear to have a synergistic effect in
patients with alopecia areata. A common protocol for this form
of treatment is to apply 0.5% anthralin cream to the affected
scalp for 5 to 10 minutes daily. The scalp is then thoroughly
washed with soap or shampoo and topical 5% minoxidil, is then
applied in the usual fashion to the scalp. Minor irritation and
mild facial hypertrichosis occasionally occur with this treatment.
No single best treatment has been identified for alopecia areata,
but treatment with minoxidil usually leads to improvement, at
least with the less extensive variants. If a response is not evident
within 4 to 6 months, an alternative treatment should be tried.
Side
effects of minoxidil use
An increase in the absorption of minoxidil from the scalp can
occur in patients with inflamed or abnormal scalps, leading to
side effects. These side effects of Minoxidil can be minimized
by keeping dosage to the recommended levels. The most common side
effects are limited to itching, inflammation and redness at the
site of application. Rare cases of allergic contact dermatitis
and photo allergic contact dermatitis have been reported with
topical Minoxidil use. The facial hypertrichosis (abnormal growth
of unwanted hair) resolves within months of stopping the drug.
Oral minoxidil can also cause a fall in blood pressure, an increase
in the heart rate, and weight gain (fluid retention). Patients
with heart failure or significant coronary heart disease should
avoid minoxidil because of these side effects.
Minoxidil
for alopecia areata references
- Shapiro J, Tan J, Ho
V, Abbott F, Tron V. Treatment of chronic severe alopecia
areata with topical diphenylcyclopropenone and 5% minoxidil:
a clinical and immunopathologic evaluation. J Am Acad Dermatol.
1993 Nov;29(5 Pt 1):729-35.
- Khoury EL, Price VH, Abdel-Salam MM,
Stern M, Greenspan JS. Topical minoxidil in alopecia areata:
no effect on the perifollicular lymphoid infiltration. J Invest
Dermatol. 1992 Jul;99(1):40-7.
- Ranchoff RE, Bergfeld WF, Steck WD, Subichin
SJ. Extensive alopecia areata. Results of treatment with 3%
topical minoxidil. Cleve Clin J Med. 1989 Mar-Apr;56(2):149-54.
- Fransway AF, Muller SA. 3 percent topical
minoxidil compared with placebo for the treatment of chronic
severe alopecia areata. Cutis. 1988 Jun;41(6):431-5.
- Fiedler-Weiss VC, Rumsfield J, Buys CM,
West DP, Wendrow A. Evaluation of oral minoxidil in the treatment
of alopecia areata. Arch Dermatol. 1987 Nov;123(11):1488-90.
- Fiedler-Weiss VC. Potential mechanisms of minoxidil-induced
hair growth in alopecia areata. J Am Acad Dermatol. 1987 Mar;16(3
Pt 2):653-6.
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(1% and 5%) in the treatment of alopecia areata. J Am Acad Dermatol.
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minoxidil. Arch Dermatol. 1984 Apr;120(4):457-63.
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stimulation. Br J Dermatol. 1987 Dec;117(6):759-63.
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characterization of the cellular infiltrate in severe alopecia
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JA. Topical minoxidil dose-response effect in alopecia areata.
Arch Dermatol. 1986 Feb;122(2):180-2.
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used topically for severe alopecia areata. Acta Derm Venereol.
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areate alopecia. Acta Derm Venereol. 1985;65(2):172-5.
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in the treatment of alopecia areata. Br Med J (Clin Res Ed).
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treated with topical minoxidil. J R Soc Med. 1982 Dec;75(12):963-5.
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