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Hair loss (Alopecia)
These lectures are not meant to replace your physician and are simply provided as
a free educational service to all our visitors. If you feel that you have a
skin problem, please see your doctor.
In the past few years, dermatologists have seen an increasing number of adult
coming for consultations because of hair loss. In most of these cases,
examination of the scalp and a careful history seeking the common diseases that
cause hair loss does not show any abnormality. These hair loss problems usually
are the result of an alteration in the rate of hair production as controlled by
the natural cycle that the scalp follows in growing hair, or a hereditary
natural decrease in the amount of hair a person is to have with aging and
hormonal changes, or an increased hair fall related to an improper grooming
technique which causes excessive pulling or traction of the hair.
Dermatologists believe that these types of hair loss were always around but
that the increasing emphasis on cosmetic appearance in our society makes people
more aware of an hair loss. The availability of dermatologic consultation and
the educational emphasis on medical examination and treatment for all diseases
is bringing more patients with alopecia to dermatologist.
Where there is no specific infectious or inflammatory scalp disease known to
cause hair loss there is no treatment that will cause hair to grow unless the
body intends to do it on its own. Hereditary pattern hair loss in not
benefitted by any non-surgical treatment whatsoever. Dandruff and seborrheic
dermatitis of the scalp do not cause baldness. Many persons have spent large
sums of money on worthless special creams, shampoos and treatments, have bought
special combs, brushes and other apparatus only to learn that it was all a
waste.
HOW HUMAN HAIR GROWS: THE HAIR CYCLE
To best understand the problems of hair loss you must first understand how hair
grows. Hair does not grow like grass. If it did you would expect every hair to
be growing at the same rate on your scalp. At the end of a even period of time
all the hairs would end their life span together and fall out together. This
would leave you totally bald until a new crop began to grow. The hair growth
cycle, which is affected by many things, prevents these episodes of total
baldness. Every hair is growing at a different rate on your scalp. At any one
time about 80% of the hairs are in a growing phase. About 15% have stopped
growing and are waiting to enter the stage when they can fall. About 5% of the
hairs are available to fall at any given point in time. You can normally lose
up to 500 hairs per day. Once a hair falls, the body immediately gets busy in
growing a new hair. There is nothing you can rub on the scalp or take as a
medicine that will make this new hair grow out faster if the body wants to grow
a new hair there.
HAIR LOSS DUE TO EFFECTS ON THE HAIR CYCLE
Many circumstances effect the hair cycle so that at a given time more than 5%
of the hairs are available to fall out. These conditions must be tolerated by
the patient until natural factors correct the hair cycle or stabilize it at a
new percentage. Factors such as heredity, age, hormones, and shocks to the
system such as fever, infection, pregnancy, and medications such as birth
control pills all affect this system.
Pregnancy and birth control pills act in a similar way to keep a large number
of hairs, through hormonal support, in a growth phase for a long period of
time. When the pregnancy ends or the pills are stopped or the body escapes from
the effect of the pill on the hair cycle a large number of hairs which should
have fallen out a long time ago are now going to fall out over a short period
of time until the hair cycle recovers This condition will last a short period
of time until the hair cycle "normalizes". This condition will last up until
all of the hairs are lost that must fall - about six months. Treatments here
are of no value since the body will correct the condition itself.
GROOMING TECHNIQUES AND HAIRLOSS
Tight roller curlers, tightly braided hair styles and teasing are a frequent
cause of hair loss as a result of constant low grade traction or pulling on the
hair. This removes the 5% of the hairs destined to fall at a faster rate and
may even remove some of the older resting hairs. Where this is the condition,
the recommendation will be to stop this grooming style completely and try a
different hair style that does not require this. In all cases of hair loss this
should be avoided in order to hold in the hairs you have for as long as
possible.
Male pattern Baldness/ Female pattern Baldness
Common "male pattern" baldness results from the combination of adequate
androgen (gonad derived hormone) levels and the appropriate genetic background.
The term androgenetic alopecia is appropriate and makes reference to both
requisite factors: androgens and a genetic predisposition. Both men and women
are affected by this process but the patterns of hair loss are quite distinct.
In males hair loss usually occurs in the frontotemporal and vertex (top) areas.
In females, it tends to be more diffuse and generalized.
Androgenetic alopecia results from transformation of terminal hair follicles
into vellus-like (immature) follicles, which then become atrophic and waste
away. The progression is gradual and the process may become noticeable after
puberty in either sex.
Topical treatments such as minoxidil (Rogaine) have been shown to slow the
progression of hair loss as well as cause hair regrowth. The mechanism is not
completely understood but may be related to the effect of minoxidil directly
stimulating the hair follicles. Recently, oral therapy with finasteride
(Propecia) has been shown to be effective at halting hair loss and causing hair
regrowth. The mechansim of this medication is directly related to the
inhibition of production of androgens and thus dimished stimulation of
transformation of terminal hair follicles to vellus hair follicles.
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