N E W P A G E G O E S H E R E F O R MICRODERMABRASION It is genetically determined but
is equal in both sexes. Thus, the number of hair follicles/skin
area is greater in Caucasians than in Orientals and
greater in Mediterranean than in Nordic individuals.
Hair grows from hair follicles within the skin. There
are about 50 million hair follicles covering the body
of which one fifth is located in the scalp. Only the
soles and palms are free of hair follicles. As long
as follicles are not destroyed hair continues to grow
even if it is plucked, depilated or removed in any other
fashion.
There are two types of hair as an adult; vellus hair
and terminal hair. Vellus hairs are soft, tine, and
usually short. They may be colorless giving the impression
of hairless skin. Examples of vellus hair in women can
be found on the face, chest, back, etc. Terminal hairs
are longer, coarser, and thicker such as those found
in the scalp, pubic area, and axilla of both men and
women. In men, they are also found in the face and body.
Hair growth occurs in cycles, but because hairs in
the human are usually not in phase with each other (some
are growing, some are resting, some are falling), they
give the impression of continuous growth. The duration
of this growth phase (also called anagen) determines
the maximum length of hair in a particular area. For
instance, in the scalp anagen lasts three years with
a short resting phase (telogen). Thus 10-15% of the
hairs are in the resting phase at any given time. In
other areas (for instance, the arm), a short anagen
and a tong telogen phase results in short hair of stable
non-growing length. Rapid hormonal changes (i.e. pregnancy,
birth control pills) may cause hair to synchronize growth
cycles. Thus, increasing numbers of hair grow and fall
out at the same time, giving the impression of shedding.
Various hormones control hair growth. Thyroid hormone
and growth hormone affect hair growth. The most important
hormone controlling growth are “androgens”,
commonly known as male hormones. The most important
one is testosterone. Except in the scalp, androgens
cause hair to change from vellus to terminal.
A good example is puberty, which in both sexes’
androgens induce the appearance of pubic and axillary
hair. Estrogens or female hormones have the opposite
effect. Once vellus hair has been transformed
into terminal hair, it cannot change back even if androgens
disappear. Therefore, hirsutism must he treated
promptly to minimize the number of terminal hair
induced by excess androgens.
What constitutes Hirsutism in Women? All women have terminal
hair in some parts of the body, specifically the scalp,
pubic and axillary area. A few hairs around the nipple
or over the thighs may be normal. Hirsutism or excess
body hair in women is the presence of thick (usually dark)
hair over the face, chest, abdomen, upper thighs, and
upper arms. There is no hirsutism if only the forearms
and calves are affected.
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