· Baldness in men
Hair grows about an inch every couple of months. Each hair grows
for 2 to 6 years, remains at that length for a short period, then
falls out. A new hair soon begins growing in its place. At any
one time, about 85% of the hair on your head is in the growing
phase and 15% is not.
Each hair sits in a cavity in the skin called a
follicle. Baldness in men occurs when the follicle shrinks over
time, resulting in shorter and finer hair. The end result is a
very small follicle with no hair inside. Ordinarily, hair should
grow back. However, in men who are balding, the follicle fails
to grow a new hair. Why this occurs is not well understood, but
it is related to your genes and male sex hormones. Even though
they are small, the follicles remain alive, suggesting the possibility
of new growth.
Typical male pattern baldness involves a receding
hairline and thinning around the crown with eventual bald spots.
The hairline gradually recedes to form an "M" shape.
The existing hair may become finer and shorter. The hair at the
crown also begins to thin, and eventually the top of the hairline
meets the thinned crown. Ultimately, you may have only a horseshoe
ring of hair around the sides.
In addition to genes, male-pattern baldness seems to require the
presence of the male hormone testosterone. Men who do not produce
testosterone (because of genetic abnormalities or castration)
do not develop this pattern of baldness.
Hair loss in patches, diffuse shedding of hair,
breaking of hair shafts, or hair loss associated with redness,
scaling, pain, or rapid progression could be caused by other conditions.
· Baldness in women
Hair grows from its follicle at an average rate
of a 1/2 inch per month. Each hair grows for 2 to 6 years, then
rests, and then falls out. A new hair soon begins growing in its
place. At any one time, about 85% of the hair is growing and 15%
is resting. Baldness occurs when hair falls out but new hair does
not grow in its place.
The typical pattern of female pattern baldness is different than
that of male pattern baldness. The hair thins all over the head,
but the frontal hairline is maintained. There may be a moderate
loss of hair on the crown, but this rarely progresses to total
or near baldness as it may in men.
Some women also develop a particular pattern of
hair loss due to genetics, age, and male hormones that tend to
increase in women after menopause. The pattern is different from
that of men. Female pattern baldness involves a thinning throughout
the scalp while the frontal hairline generally remains intact.
The cause of the failure to grow new hair in female pattern baldness
is not well understood, but it is associated with genetic predisposition,
aging, and levels of endocrine hormones (particularly androgens,
the male sex hormones).
Changes in the levels of androgens can affect hair
production. For example, after the hormonal changes of menopause,
many women find that the hair on the head is thinned, while facial
hair is coarser. Although new hair is not produced, follicles
remain alive, suggesting the possibility of new hair growth.
Hair loss can occur in women for reasons other than
female pattern baldness. These may include temporary shedding
of hair (telogen effluvium), breaking of hair (from such things
as styling treatments and twisting or pulling of hair), patchy
areas of total hair loss (alopecia areata -- an immune disorder
causing temporary hair loss), some medications, and certain skin
diseases. Sometimes female pattern baldness is permanent.
Female pattern baldness is of cosmetic importance
only and does not indicate a medical disorder, unless diagnosed.
However, male or female baldness in men and women, respectively,
may affect self-esteem or cause anxiety with psychological stress
due to change in appearance.