CAUSES
OF HAIR LOSS
With
the hormonal changes of aging comes a decrease in the number
of active hair follicles. Though this is an essentially
universal change in all of us, a number of hormonal, genetic,
or disease states make some of us lose hair earlier in life.
ANDROGENETIC
ALOPECIA
The most common cause of hair loss is known as androgenetic
alopecia, or male pattern baldness (in men), and female
pattern baldness (in woman).
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MALE
PATTERN BALDNESS
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Male
pattern baldness is something that 7 - 15% of American males
experience by age 25, and almost 40% by age 35. It is a
natural, age-related change in the body, and represents
over 95% of all hair loss in men. The exact reason and
cause of male pattern baldness is not known, though it is
clear that our GENETIC makeup is a huge part of it. The
HORMONE androgens discussed previously (like testosterone
and dihydrotestosterone) also play a big part. Roughly
put, the more androgens you have, the faster you lose your
hair. The loss of hair follows a horseshoe-shaped pattern
(shown in the graphic), with the hair on your sides and
back of the head generally being left untouched. You can
assess your chances of developing male pattern baldness
by looking at your male relatives, starting with dad and
grandfathers (most telling is your mother's father's hair
pattern - if he has it, you are at high risk). The male
pattern baldness genes can come from your mother just as
easily, but may be less noticeable since it's often slower
to develop in women. Male pattern baldness often begins
slowly at puberty, but may then come on very fast or not
at all.
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FEMALE
PATTERN BALDNESS
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For
woman, female pattern baldness is the most common type of
hair loss (also called androgenetic alopecia). It affects
about 20 million women in the US alone, and is highly correlated
to GENETICS. It can begin at puberty, but is most often
seen after menopause. As we discussed previously, male
and female pattern baldness happens when hair that falls
out is no longer replaced. Female pattern hair loss is
generally a change to thinning hair rather than just falling
out, and is more noticeable on the top of the head.
TELOGEN
EFFLUVIUM (STRESS TRIGGER)
Whether it's a death in the family, pregnancy, illness,
crash weight loss program, or worrying about a huge asteroid
hitting the earth, body stressors can affect the hair follicle.
What is believed that the stressor causes a major change
in a large portion of the hair follicles, moving them from
the anagen growth phase to the catagen then telogen rest
phase. The follicle then lets go of the hair that's already
there while refusing to provide a replacement. Known as
telogen effluvium / deffluvium, it is the second most common
cause for hair loss after androgenetic alopecia. Through
an unclear set of neurochemical events, the hair follicle
gets the message that the body needs all the resources it
has for more important things than hair, like childbirth
and nursing. It usually affects small, circular patches
of the scalp in no apparent pattern. The good news is, when
the stress goes, the hair comes back (about 6 months later).
Although
hair loss can occur with the stress of any illness, it is
also a particular symptom of many different diseases. Most
differ in the pattern of hair loss, and almost never resemble
Male Pattern Baldness. It's also important to recognize
that hair loss is seldom the first and only presentation
of these diseases. Most hair comes back when the disease
goes away or is adequately treated. Some of the diseases
associated with hair loss are as follows: Addison's disease,
Hyperthyroidism (Hashimoto's thyroditis), Hypothyroidism,
Iron Deficiency, Scarring, Seborrheic Dermatitis, Secondary
Syphilis , Systemic Lupus Erythematosus (SLE), and Vitiligo
(there are others).
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traction
alopecia
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traction
alopecia
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Two
particularly interesting forms of hair loss are traction
alopecia and trichotillomania. Traction alopecia
is hair loss due to excessive and chronic pulling, or traction,
on hair. It commonly occurs in people who braid or knot
their hair. There is pronounced traction alopecia in the
beard area of this Sikh man. In the Sikh religion, men
do not cut scalp or beard hair. The beard hairs are pulled
straight and then twisted and tightly knotted. Daily knotting
often results in this form of traction alopecia.
Trichotillomania
is the intentional pulling out of otherwise heathly hair.
Most commonly, it is a temporary habit of no consequence.
Sometimes, however, it is a symptom of a psychiatric or
serious emotional problem. Most often seen in children
and young adults, the pulling out of individual strands
of hair has been associated with thumb-sucking and other
habitual rituals. Usually scalp hair is pulled, though
eyebrows, eyelashes, or pubic hair may be involved. Often
the pulled hair is manipulated in a ritualized way (such
as wrapping around a finger) before being discarded.
ALOPECIA
AREATA
Alopecia
areata is the development of patches of baldness, usually
in small circular areas of the scalp. It is relatively
common, affecting about 1 out of every 100 people in the
US population. It is generally thought to be autoimmune
(where the body's own cells and antibodies attack the body
itself - in this instance the hair follicle, specifically
the papilla/bulb area).
This
disease usually affects young adults, and occurs equally
in men and woman (though it is more common in men in Italy
and Spain). About 80% of people with alopecia areata eventually
regrow most, if not all, of their hair. Many people, however,
will have recurrent battles with this condition.
A
severe form of alopecia areata is the total loss of scalp
hair (alopecia totalis) and even sometimes the complete
loss of all body hair (alopecia universalis). About 33%
of those afflicted with these rare problems will grow back
all their hair within a year, though again, recurrences
do occur.
ANAGEN
EFFLUVIUM (CHEMICAL DAMAGE)
Like
Telogen effluvium, this form of hair loss initially causes
patchy loss of hair (which often then advances to total
hair loss). In this form of hair loss, rather than just
shutting down the hair follicle, a chemical actually kills
the hair follicle and anagen hair. The most common example
of this are the effects of drugs used to treat cancer. Chemotherapy
is medicine that's injected into the body to kill cancer
cells. In effect, it's really a poison that's designed
to kill more bad cells (i.e., the tumor cells) than good
cells. One of the side effects is the poisoning of the
hair follicle. The good news is, when the chemotherapy
stops, the hair comes back (also about 6 months later).
Other
drugs also can cause hair loss. Many medicines used to treat
even common diseases can cause hair loss. Most do so by
unknown mechanisms, and most of the drugs known to do this
only cause hair loss in a small minority of patients. Click
here for a list of the medications that are known to
cause hair loss in a small percentage of patients. Obviously,
be sure to you ask your doctor before discontinuing a medication
as some of these medicines require a slow taper to avoid
complications.
