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Alopecia occurs in both men and
women, and is considered normal in adult males. Also
known as male
pattern baldness, (It is easily
recognized by the distribution of hair loss
over the top and front of
the head (leaving a horseshoe pattern of
hair) and
by the
healthy condition of the scalp.
Women with androgenetic alopecia experience hair thinning, particularly
over the
top of
the scalp. The disorder is
considered
to be caused
by a genetic predisposition
that
triggers the production of certain
enzymes that convert testosterone into the
hormone dihydrotestosterone
(DHT).
Alopecia areata and
alopecia circumscripta refer to hair loss conditions that can be
patchy
or extend to complete baldness. The exact
cause of alopecia areata is
unknown, but it is thought to be triggered
by an immune system disorder.
Many times, conditions
affecting the skin of the scalp will result in hair loss. The first
clue
to the specific cause is the pattern of
hair loss, whether it be complete baldness ,
patchy bald spots,
thinning, or hair loss confined to certain areas.
Sometimes only the
hair is affected; sometimes the skin is visibly
diseased as well.
Fungal infections of
the scalp usually cause patchy hair loss. The fungus, similar to the
ones that cause athlete’s foot and ringworm, often
glows under ultraviolet light.
Complete hair loss is a
common result of cancer chemotherapy, due to the toxicity of
the drugs
used.
Systemic diseases often affect hair growth either selectively or by
altering the skin of
the scalp for example thyroid disease.
Several autoimmune
diseases like lupus erythematosus also cause hair loss.
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