it's normal 
Normally,
about 90% of our scalp hairs are growing and 10% are resting.
The resting hairs stay in place for several months, but when a new
hair is formed and begins its own growth cycle, the old one is
pushed up and out. We normally lose 50 - 100 scalp
hairs per day as old hairs are shed to make room for new
ones.
Many events
can cause a definite change in the hair cycle. A temporary
increase in the rate of shedding may occur 3 - 4 months after
childbirth, or following a high fever, major illness, major
surgical procedure, blood loss, or severe emotional stress.
It has also been seen recently in association with rapid
weight-loss diets involving severe restriction of calories (less
than 800 per day) or protein. In these situations, hair will
literally come out by the handful, but it always regrows some
months later. Various drugs can also cause hair
shedding. In other instances, hair loss is not increased but
replacement is inadequate. This can occur as a result of
thyroid disease, cancer, iron deficiency, and some cases of
diabetes.
So-called
"male-pattern" hair thinning, the all-too-familiar receding
hairline seen earliest at the temples and over the top of the
scalp, is very common in men. It may also occur in women, in
whom it normally appears 15 - 20 years later than in their male
relatives. The age of onset, degree of thinning, and ultimate
hair pattern are determined by male hormone (androgen) stimulation
and by heredity. In other words, the eventual development of
male-pattern thinning is a normal and inevitable response to the
same stimuli (androgen) which promote normal sexual
development. Although seborrhea (oilness) and dandruff are
sometimes associated with this type of hair loss, treating these
conditions does not influence the regrowth of hair.
In women,
genetic hair thinning is more difficult to diagnose with certainty
at an early age, but it seems to be quite common. The hair
loss is more diffuse and less patterned. If one can exclude
other common causes of hair loss, if there is a family history of
the condition, and if the onset is gradual and not associated with
irregular menstrual periods or excessive growth of hair elsewhere
on the body (hirsutism), it is likely that this hair loss is a
normal event.
Familial
(or genetic) hair thinning has never been shown to be helped by
local applications or injections, by radiation, or by any other
physical treatment in either sex. There are no foods or
vitamins which will specifically help hair growth, though food
health and nutrition are generally important.
