Male pattern baldness is a form of baldness which affects most
men and some women. It is also known as common baldness or androgenetic
alopecia, a name which suggests it has something to do with
androgens and genes.
Male pattern baldness may be due to three factors:
Androgens
Androgens are influential for the following reasons.
Women who produce excess androgens can develop very severe
male pattern baldness. It has also been found that the hair
follicles of individuals with male pattern baldness convert
circulating androgens to more potent androgens at a faster rate
than normal follicles. These androgens accumulate in the skin
and cause the hair follicles there to regress.
Male pattern baldness develops as a result of this. The increase
in androgens occurs locally, which is why many individuals with
male pattern baldness have normal levels of circulating androgens,
and women with male pattern baldness still look feminine and
can conceive and have babies normally.
The importance of androgens is further illustrated by the following
report by Dr James B. Hamilton of the State University Medical
Center in New York City in the American Journal of Anatomy.
In an identical twin study, one twin who had been castrated
before puberty retained all his hair at 40 but his uncastrated
twin brother had slowly become bald. When the castrated twin
was treated with testosterone (an androgen), he became as bald
as his twin brother within six months.
Genes
Genes are the blueprints of our body, and several thousands
of these can be found on paired structures called chromosomes.
We inherit one chromosome from each of our parents. Many of
our characteristics such as the colour of our hair and eyes,
height and facial appearance are inherited. This is why there
is often a resemblance between family members.
The tendency to develop male pattern baldness is also believed
to be inherited. According to one theory, men who inherit one
or both genes for male pattern baldness will develop it whereas
only women who inherit both genes are affected.
Genetic Make-up Men Women
Bb Bald Normal
BB Bald Bald
bb Normal Normal
(where B is the gene for male pattern baldness.)
However, not everyone agrees with this theory and it is likely
that the genetics of male pattern baldness is much more complex.
The importance of inheritence is illustrated by Dr Hamilton's
observations that a eunuch with normal male relatives did not
develop male pattern baldness, whereas one whose male relatives
were affected tended to develop male pattern baldness when treated
with the same amount of androgens.
Age
Male pattern baldness becomes more common as a person ages.
Significant male pattern baldness, defined as at least a deep
receding of the front hairline, occurs in 5% of men under 20,
30% of men at the age of 30, and 50% of men at the age of 50.
You may recall that the number of hair follicles decreases
with increasing age and hair becomes thinner as a result. It
seems to affect the same areas affected by male pattern baldness,
accentuating it.
Theoretically, male pattern baldness can occur at any age after
puberty. In men, it commonly develops during the 20s and 30s.
Women usually develop male pattern baldness after menopause
unless they have inherited susceptible genes. If so, male pattern
baldness may begin just as early.
Fortunately, male pattern baldness in women is never as severe
as in men because the female hormone, oestrogen, Counteracts
the effect of androgens on the hair follicle. However, if it
is severe in young women, this may indicate excess androgen
secretion. Besides menstrual qisturbances, these women usually
suffer from infertility, hirsutism (excessive and coarse facial
hair, particularly on the upper lip, chin and cheeks), and severe
acne. Hormone investigations need to be done.
In men, male pattern baldness usually begins as a receding
hairline along the front and temples (Fig. 8) and then a thinning
of the crown. In severe cases, these areas merge until only
a horseshoe rim of hair remains on the sides and back.
Severe male pattern baldness in young men is, fortunately,
not very common and affects only 2% of them by the time they
reach 30. Severe male pattern baldness is not normally seen
in women and the pattern of baldness is also different. Women
usually develop diffuse thinning of the crown rather than a
receding hair line. Figs. 9 and 10 illustrate the pattern of
male pattern baldness in men and women.
In male pattern baldness, there is a reduction in the duration
of anagen and a consequent increase in telogen hairs. This is
reflected in a lower anagen:telogen (A:T) ratio. Shorter hairs
are produced because of the shortened anagen stage. The hair
follicle also shrinks in size over each successive hair cycle.
Consequently, the hairs produced are finer and lighter in colour.
Initially, indeterminate hairs are produced. These are intermediate
in length, thickness and colour between terminal and vellus
hairs. Eventually, even these are reduced to a fluff. Another
characteristic finding in male pattern baldness is the discovery
of telogen hairs of different thickness. It is due to hair follicles
of different sizes entering telogen.
You may recall that under the influence of androgens, vellus
hair on some parts of the body such as the face, chest, armpits,
and pubic region changes to coarse, pigmented terminal hairs.
On the scalps of individuals with male pattern baldness, however,
the same androgens seem to do the opposite-cause terminal hairs
to revert back to vellus hairs. That androgens should exert
opposite effects on hairs on the scalp and hairs elsewhere is
a paradox.
There is also racial variation in the severity of male pattern
baldness. Caucasians, for example, have the most severe form
of male pattern baldness. Blacks have less severe forms and
Orientals the least.
Seborrhoea (increased sebum or oil production) often accompanies
male pattern baldness. This is because the sebaceous glands
are stimulated by the same androgens that cause male pattern
baldness.
Diagnosis
The pattern of male pattern baldness is quite characteristic
in men, but the diagnosis may be more difficult to make in women.
A positive family history, if present, may help. If necessary,
the diagnosis can be confirmed by determining the anagen:telogen
(A:T) ratio.
The A:T ratio is normally at least 4: 1, but in male pattern
baldness, it is reduced in the areas that are affected by it.
The presence of telogen hairs of different diameters also suggests
male pattern baldness.
Treatment
Treatment is not necessary if male pattern baldness is mild
and the person is not distressed by it. But the following treatments
are available:
Minoxidil
Minoxidil is a drug used for the treatment of severehypertension
(high blood pressure). One of its side effects is increased
hair growth, often in unwanted places. However, its potential
as a hair growth restore-r largely went unrecognized until Dr
Anthony R. Zappacosta, an American cardiologist, reported in
the New England]ournal of Medicine that one of his patients,
a bald man of 38, had experienced hair re-growth after treatment
with minoxicil. Soon, dermatologists were dissolving minoxidil
and applying the lotion on bald scalps.
Upjohn Company, the manufacturer of minoxidil, also started
its own trials on minoxidil. Initial studies were conducted
on stumped tail macaque monkeys who also developed male pattern
baldness during adolescence. The results were impressive; the
animals started to grow new hair.
Subsequently, trials in human were conducted in several centers
throughout the world. These more or less confirmed that 2% minoxidil
lotion helps some cases of male pattern baldness affecting the
crown.
However, the following points need to be emphasized about minoxidil:
1. Minoxidil lotion only helps male pattern baldness affecting
the crown. It does not seem to help the receding hairline.
2. Not all patients respond to minoxidil lotion. The commonly
quoted figure is 20_SO% cosmetically acceptable improvement.
The term "cosmetically acceptable" means a satisfactory improvement
in appearance, not complete re-growth. In my experience, minoxidil
does not produce complete re-growth. Some patients show dense
re-growth, but this is rare and occurs in less than 10% of cases.
3. Minoxidil works better in men below the age of 40 if the
baldness is less than 10 years old, if the bald patch is less
than 10 centimeters in diameter, or if there are more than 100
indeterminate hairs in a 2.S_centimetre diameter area in the
centre of the bald area.
4. The minoxidil lotion has to be used for at least. four months
before signs of re-growth become visible. Perseverance is necessary
during this period.
5. Maximum re-growth is seen at eight to 10 months, after which
there is little improvement.
6. Once regrowth is achieved, minoxidil must be continued or
the re-grown hair will start to fall out. Minoxidil is expensive
and the cost of treatment is considerable.
Minoxidil is no miracle drug, but it is the best treatment
available for male pattern baldness. It is up to you to decide
whether it is worth spending your money on it, keeping in view
the above considerations.
Some studies have suggested that although minoxidil does not
induce regrowth in some patients, it does appear to prevent
further loss as long as it is used regularly. Minoxidil may
therefore have a prophylactic (preventive) action against baldness.
Again, the problem is cost.
However, minoxidil lotion appears to be safe to use on people
with a normal heart. Systemic side effects such as lowered blood
pressure and palpitations are uncommon because very little minoxidil
is absorbed through the skin. Still, patients on it should have
their blood pressure checked regularly.
Minoxidil should also not be used on scalps that are damaged
by eczema or cuts because of the possibility of increased absorption
through the damaged skin. Minor side effects such as itching,
prickling and dryness of the skin and skin allergy may sometimes
occur.
Minoxidil promotes hair growth by prolonging anagen (the growth
stage). There are two possible mechanisms of action. Minoxidil
reduces blood pressure by causing the blood vessels to dilate,
and it has been suggested that the dilation of the small blood
vessels in the papilla of the hair follicle stimulates hair
growth.
Interestingly, another anti-hypertensive drug, diazozide, reduces
blood pressure in the same way and also causes increased hair
growth as a side effect. This theory presumes that male pattern
baldness is partly due to a reduction of blood flow to the papilla,
but this is unlikely because grafts of hair-bearing skin transplanted
onto the bald areas do not start to lose hair, which it should
do if the blood supply to the papilla is the determining factor.
The second mechanism is a direct stimulation of hair follicle
cell growth. Experiments have confirmed that minoxidil can stimulate
the division and prolong the survival of these cells. This,
I feel, is the most likely mechanism.
Most of the published studies on minoxidil have involved men
and the question on many people's minds has been: "Does minoxidil
help male pattern baldness in women?"
Theoretically, at least, minoxidil should work but the question
is how well. Unfortunately, this question cannot be answered
at the moment because there is very little published data on
the use of minoxidil in women with male pattern baldness.
There has also been a recent report that treatment with low
concentration minoxidil and tretinoin is even more effective.
Topical tretinoin
Tretinoin is a vitamin-A derivative originally developed for
the treatment of acne (pimples). It is known to stimulate the
division of epithelial cells and also promotes the formation
of new blood vessels in the skin.
Tretinoin has aroused great interest recently because it was
reported to delay skin ageing and reverse early wrinkles. There
has been a report by Dr Gail Bazzano and her colleagues in New
Orleans which suggests that tretinoin lotion also stimulates
hair growth. The investigators treated patients with 0.5% minoxidil,
0.025% tretinoin, a combination of both drugs, and placebo (dummy
drug). No hair growth was observed with minoxidil (however,
note that this is lower than the 2 % concentration recommended
for male pattern baldness) or placebo, but 58% of the patients
treated with tretinoin showed signs of re-growth.
Re-growth was even more impressive with the combination of
minoxidil and tretinoin-66% responded positively. This study
suggests that tretinoin has potential as a hair-growth restorer
and is particularly effective when combined with a low concentration
of minoxidil. This is certainly interesting but needs further
confirmation.
Cyclical anti-androgen therapy
Oestrogen, you may remember, protects against male pattern
baldness whereas androgens encourage it. It has been combined
with anti-androgens to block the effects of androgens on the
hair follicle to treat male pattern baldness.
The anti-acne drug, Diane, combines ethinyl oestradiol (an
oestrogen) with cyproterone acetate (an anti-androgen) and has
been reported to induce hair growth in some women With male
pattern baldness. It cannot be used in men because of the risk
of feminization.
Some dermatologists feel that the dose of cyproterone acetate
in Diane is too low and usually give patients an extra tablet
of cyproterone acetate.
Steroid-oestrogen therapy
This involves the use of a steroid like prednisolone and an
oestrogen. Prednisolone suppresses the production of androgens
by the adrenal glands and oestrogen counteracts the effects
of androgens on the hair follicle. This form of treatment has
been reported to help some women. Unfortunately, it is also
unsuitable for men because of the risk of feminization.
Topical (applied) oestrogen and progesterone
Oestrogen and progesterone are female sex hormones. Topical
oestrogen works by inhibiting androgen production, but this
may have undesirable effects in men.
Topical progesterone has been advocated on the basis that application
to the pubic skin of normal males inhibited the conversion of
testosterone to DHT (a potent androgen). It may retard the progression
of male pattern baldness.
ToPical ant-androgens
Anti-androgens block the effect of androgens on the hair follicle.
However, they cause feminization when taken orally. Topical
(applied) anti-androgens have been used instead in men, but
the results have not been encouraging.
One topical anti-androgen, 11 alpha-hydroxypro gesterone, has
been reported to have an effect, but this was based on very
fine measurements such as the diameter of the hair shaft rather
than observable re-growth (which is important when dealing with
a cosmetic problem). Nonetheless, this is a very promising area
for research and it is possible that an effective topical anti-androgen
will eventually be found.
Spironolactone
This is an oral drug used for treating water retention or oedema.
It also has anti-androgenic properties and has been reported
to help women with male pattern baldness.
However, spironolactone commonly causes menstrual irregularities
in women if taken on its own. This can be avoided by taking
a combined birth control pill during. the first 21 days of a
28_day menstrual cycle. Spironolactone cannot be used in men
because it causes gynaecomastia (breast enlargement).
Cimetidine
This is an oral, anti-ulcer drug which also has anti_ androgenic
properties. It has been reported to help a few women with male
pattern baldness. However, cimetidine is also known to cause
hair loss as a side effect. This seems strange for a drug that
is supposed to help hair grow. Other side effects include diarrhoea,
rashes and dizziness.
Cyclosporin
It suppresses the body's immune system and is used to prevent
the rejection of transplanted organs. It promotes hair growth
as a side effect and has been reported to induce re-growth in
some patients with alopecia areata.
There has also been a report of a male patient re-growing hair
while taking cyclosporin. It may work by directly stimulating
hair follicle cell growth. Unfortunately, cyclosporin is rather
toxic (especially to the kidneys) when taken orally, so doctors
have tried to overcome this by applying it externally instead.
Unfortunately, the results have been disappointing, probably
because topical cyclosporin has difficulty penetrating the skin
and cannot reach the follicles. Doctors are still trying out
different formulations of topical cyclosporin to overcome this.
Diazozide
This is another drug used for treating hypertension. Like minoxidil,
it too causes the blood vessels to dilate (thus lowering blood
pressure) and hair growth as a side effect.
Trials are already in progress to determine the effectiveness
of topical diazozide in the treatment of male pattern baldness.
Its manufacturer, Schering USA, is rather tight lipped about
the results and any information apart from the fact that trials
were in progress could not be obtained. It remains to be seen
whether topical diazozide will eventually prove to be effective.
Cosmetic therapy
This includes creative hair styles, wigs and surgery to disguise
hair loss.
People suffering from hair loss often worry that frequent shampooing
aggravates the loss. This is not true. Indeed, the reverse may
be correct in male pattern baldness. Dr Ronald Rizer and colleagues
at the New York University Medical Center have found that the
scalp sebum contains androgens and claimed that these may re-enter
the scalp and aggravate male pattern baldness if the scalp is
not regularly shampooed.
