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Hair loss can be caused by a wide range of factors,
including genetic factors, aging, local skin conditions, diseases
that affect the body generally, and use of certain medications,
eg anti-cancer drugs.
from mechanical damage to skin infections. It is essential for
you to consult a physician to determine the exact cause of hair
loss. The followings are the most common types of
hairloss. 1,
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| 1. |
Alopecia areata
1, 2 |
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This condition generally causes coin-sized bald
patches on the scalp or beard. Rarely, all body hair may be
lost. The hair usually grows back in several months, except
in people with widespread hair loss, for whom re-growth is unlikely
(or other parts of the body). Scientists are not sure what causes
alopecia areata. It is probably caused by a combination of factors
including genetic predisposition, predisposition to allergy,
immune and autoimmune system responses, and emotional stress.
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| 2. |
Telogen effluvium 1 |
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Telogen effluvium is a type of hair loss that
occurs when hair follicles are shifted into the telogen (or
resting) phase prematurely. It causes a general thinning of
the hair. Telogen effluvium can be triggered by nutritional
status, stress, medication, childbirth, febrile illness and
surgical operation. This type of hair loss usually remits within
3-6 months after the 3 causes is removed. |
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| 3. |
Male Pattern Hair Loss
1,
2, 3 |
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Male Pattern Hair Loss is the most common type
of hair loss in men. This is caused by genetic pre-disposition
and can affect male in any age after puberty. With male pattern
hair loss, your hair begins to thin at the temples and at the
crown. As time goes on, the hair at the temples recedes further,
leaving a central spur of hair at the front, and an increasing
bald spot at the crown. Eventually the areas of hair loss at
the front and crown meet, and the top of the head becomes increasingly
bald. Eventually all that remains is a border of hair around
the side and back of the head. |
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High Levels of
DHT Shorten the Hairs Growth Phase
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The hair roots receive nutrients from blood vessels
which contain blood cells and a hormone called testosterone.
Testosterone is converted to another hormone called dihydrotestosterone
(DHT) by the actions of enzyme called 5 alpha reductase. |
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When high levels of DHT are present in the scalps
of men genetically disposed to male pattern hair loss, the following
happens: |
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- the anagen growth phase is shortened so the
hair is shorter when it stops growing. |
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- over the life cycle of a few hairs the hairs
get progressively shorter and shorter. |
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| Stages:
4
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Adapted from Norwood OT. |
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¡@ |
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Reference: |
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| 1. |
Whiting
& Howsokn. The Color Atlas of Differential Diagnosis
of Hair Loss. Canfield Publishing. (1998) |
| 2. |
The
Merck Manual of Medical Information, Home Edition (1997) |
| 3. |
Data
on File, MSD HK. |
| 4. |
Norwood
OT. Male Pattern Baldness: Classification and Incidence.
South Med J, 68: (U): 1359 - 65. |
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