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Alopecia, commonly known as baldness, is
a set of disorders which involves the state of lacking hair where it
would normally grow, especially on the head. The most common form of
baldness is a progressive hair-thinning condition that occurs in
adult humans and other primate species. Nonetheless, the severity
and nature of condition can vary greatly; it ranges from male and
female pattern alopecia (alopecia androgenetica), to alopecia areata,
which involves the loss of some of the hair from the head, alopecia
totalis, which involves the loss of all head hair, to the most
extreme form, alopecia universalis, which involves the loss of all
hair from the head and the body. Treatment for alopecia has limited
success. The more hair lost, the less successful the treatment will
be. The psychological implications of alopecia include stress,
anxiety and depression, and can in many cases involve issues
relating to identity change, particularly when the eyebrows and
eyelashes are also lost. Hair loss is sometimes the result of
chemotherapy treatment for cancer sufferers.
Male pattern baldness is thought to occur in varying forms in about
66% of adult males at some point in their lives.[1] It is
characterized by hair receding from the lateral sides of the
forehead, known as "receding hairline" or "receding brow." An
additional bald patch may develop on top (vertex). The trigger for
this type of baldness, which is also known as androgenic alopecia,
is currently believed to be 5-alpha reductase, an enzyme that
converts the hormone testosterone into dihydrotestosterone (DHT),
which, in genetically-prone hairs on the scalp, inhibits hair
growth. Onset of hair loss sometimes begins as early as end of
puberty, and is mostly genetically determined. Male pattern baldness
is classified on the Hamilton-Norwood scale I-VIII. Early baldness
of the ordinary type(alopecia) has been thought to be autosomal
dominant in males and to be autosomal recessive in females (who
transmit the trait if heterozygous but are bald only if homozygous).
Therefore, there is no correlation between pattern baldness and the
"mother's father" myth. If this myth were the case, the condition
would have to x-linked dominant. Genes that are X-linked, and
dominant are the only type of gene in which fathers are guaranteed
to pass the gene to daughters. Looking at the condition of a
mother's father would only help in determining who will be affected
if the gene for alopecia was x-linked and dominant, which it is not.
Female pattern baldness, in which the midline parting of the hair
appears broadened, is less common. It is believed to result from a
decrease in estrogen, a hormone that normally counteracts the
balding effect of testosterone, which normally occurs in women's
blood. Female pattern baldness is being classified on the Ludwig
scale I-III.
There are several other kinds of baldness. Traction alopecia is most
commonly found in people with ponytails or cornrows that pull on
their hair with excessive force. Wearing a hat shouldn't generally
cause this, though it is a good idea to let your scalp breathe for 7
hours a day. Traumas such as chemotherapy, childbirth, major
surgery, poisoning, and severe stress may cause a hair loss
condition known as telogen effluvium. Some mycotic infections can
cause massive hair loss. Alopecia areata is an autoimmune disorder
also known as "spot baldness" that can result in hair loss ranging
from just one location (Alopecia areata monolocularis) to every hair
on the entire body (Alopecia areata universalis). |