There are many conditions where physical damage to the hair fiber results in
hair loss. Sometimes hair fiber is damaged due to the hair being improperly
formed by the hair follicles. These conditions are usually determined by
genetic defects. There are also conditions where physical damage of the hair
fiber is caused by something environmental, most often poor or inappropriate
Hair loss as a result of physical hair defects are rare compared to other
causes of alopecia, but the most common ones are listed below.
Loose anagen syndrome or loose hair syndrome involves exactly what the name
suggests, growing hair that is "loose" and easily pulled out of the hair
follicle. Loose anagen syndrome is most often first diagnosed in young
children, more so in girls than boys. Their hair never seems to grow, they
rarely need a hair cut, and the scalp hair is usually thin, especially at the
back of the scalp.
That the hair is loose and easily pulled out helps explain why the back of
the head is most affected. The repeated rubbing of a person's head on a pillow
at night pulls out more of the hair on the back of the head, whereas the front
of the scalp has less contact with the pillow and so the hair is more likely to
remain in place. The remaining hair usually does not grow very long and it can
be unruly and difficult to comb and style.
Blond-haired children ages 2 to 5 are most likely to be affected but loose
anagen syndrome can appear later in life as well. The syndrome improves with
age of its own accord in children, but development in older individuals
indicates the hair loss will be more persistent.
Why the hair is loose is not known, but the root sheaths that normally
surround and protect the hair shaft in the skin are not produced properly in
people with loose anagen syndrome. As a result, there is a lack of adhesion
between the hair shaft and the root sheath, and the hair fiber is poorly
anchored in the follicle.
There may be a genetic problem behind the syndrome and the condition can run
in families, but there are also many isolated case reports with no family
history. There are no known effective treatments for loose anagen syndrome.
Traction alopecia and trichotillomania
In terms of the mechanical action behind hair loss, traction alopecia and
trichotillomania are exactly the same. The hair is plucked out of the skin
leaving clear bald patches or diffuse, thin hair.
Traction alopecia can be caused by tight hat bands, pulling the hair into a
tight pony tail, cornrow hair styles, and anything else that pulls on the roots
of the hair. If traction alopecia continues for a long time and the same hair
is repeatedly pulled out, then the hair follicles in the skin can become so
damaged that they stop growing hair permanently.