It had been thought that most hair found in the
sink or shower, on the brush etc. was broken hair due to damage and
weathering. Studies have now shown this not to be the case. In fact at
least 80% of hair loss is from the root, not breakage.
The hair shaft is a remarkable structure that takes a great deal of
abuse, ranging from exposure to the environment, and to frequent combing
and brushing. Normal hair keeps its resiliency, flexibility, and
strength for up to 7 years, unless there are genetic defects present.
During the time that hair is on the scalp and before it is shed, there
may be some breakdown. This is often called “weathering,” which is
characterized by changes in the hair structure, generally limited to
cosmetic occurrences. Weathering is due to: “combing, brushing, and
permanent waving...natural friction, wetting, and ultraviolet
radiation.”
It had been thought that most hair found in the sink
or shower, on the brush etc. was broken hair due to damage and
weathering. Studies have now shown this not to be the case. In fact at
least 80% of hair loss is from the root, not breakage.
Data
generated by hair experts confirms this observation and extended it to a
range of ethnic communities globally. The highest rates of shedding
from the root appear in China (>90%) and in all cases (Mexico, India,
Turkey, Thailand, UK) shedding from the root was always greater than
80%.
BREAKAGE:
Breakage is characterized by broken and/or blunted ends and differs from growing hair that may have pointed or tapered tips.
Fragile
hair will easily break off near the ends: hence hair breakage. If there
is a question of broken hair, this can be confirmed in two ways:
•
Card test - hold an index card behind the hair in question (white for
darker colors and black for lighter colors). This will highlight the
broken or blunted tips of breakage.
• Tug test – grasp a few
centimeters or inches of hair from the ends. If the hair is damaged, the
held areas will fragment.10 Bubble hair can result from excessive blow
drying, flat ironing, or hot curlers due to the high temperatures
involved. This may lead to broken hair, as well as changes in texture
and strength. The hair will show bubbles within the shaft under
magnification.
Acquired trichorhexis nodosa: Although
this hair shaft fracture, which gives the picture of two brooms meshed
together, is usually due to heredity, heat, straighteners, and excessive
combing or brushing can induce it. The fractured hair gives the
appearance of nodes being present. This condition also shows cultural
differences: distal disruption is often found in Caucasian and Asian
women, while women of African descent have the problem closer to the
scalp. Attempting to brush the nodes out can cause even more damage.
HAIR LOSS:
TELOGEN EFFLUVIUM:
This represents the loss of hair due to abnormal hair cycling. The
amount of daily shedding is in excess of 100 hairs per day. If telogen
effluvium lasts for less than six months, it is called acute, and if
more than six months, it is referred to as chronic. At least 50% of the
scalp hair needs it to become lost for the loss to be clinically
visible. Acute telogen effluvium may be due to anything that increases
the body’s metabolism, such as severe illness, certain drugs, fevers, or
even iron and vitamin D deficiency. Acute telogen effluvium occurs
three to six months after pregnancy and can even appear when birth
control pills, which create a pseudo-pregnancy state, have been stopped.
The hair cycle usually returns to normal within a few to several
months.
ANAGEN EFFLUVIUM: This type of hair loss
occurs most frequently after treatment with cancer therapeutic agents
or with radiation. Mostly broken hairs, rather than hair loss,
characterize anagen effluvium. Such hair loss usually begins seven to
ten days after the start of treatment but does not become noticeable for
one to two months. It generally continues for another month after the
last treatment cycle.13 Occasionally, the new hair is weaker and more
brittle. At other times, some patients believe their hair grows back
healthier and with different coloring. In addition, people with curly
hair may find their hair straightened and vice versa. Anagen effluvium
can also occur with arsenic or thallium poisoning.
ANDROGENIC ALOPECIA (PATTERNED HAIR LOSS):
This is the most common type of hair loss (95%) in both men and women,
where there is a progressive loss of hair diameter, length, and
pigmentation.14 There is a genetic influence, but the causative genes
have yet to be found. While the precipitating factors are often unknown,
a few people have lost hair from massive weight gain or losses or from
taking prescription medicines with androgenic effects. Oral
contraceptives and hormonal replacement agents have rarely been held
responsible for inducing or aggravating androgenic alopecia.
PRESCRIPTION MEDICINE INDUCED HAIR LOSS: Infrequently,
some therapeutic agents have been known to cause hair loss. These
include: allopurinol for the treatment of gout, heparin and warfarin for
preventing blood clots, and clofibrate and gemfibrozil for lowering
cholesterol levels. ALOPECIA AREATA: This condition occurs, often
suddenly, with small, frequently rounded, patches of hair loss on the
scalp. There is the noticeable appearance of abnormal club hairs that
resemble exclamation points. While the cause is unknown, the hair
usually returns spontaneously within six to twelve months, but the
condition can recur.
TRICHOTILLOMANIA: This
self-induced hair loss results from frequent pulling and tugging of the
scalp hair, eyebrows, and even eyelashes. It occurs twice as often in
girls or women than in boys or men. Trichotillomania represents a
psychiatric problem of children and adolescents. The bald spots have
irregular borders and contain many broken hairs.
TRACTION ALOPECIA:
Such hair loss results from chronic insults to the hair follicle. When
the hair is pulled too much or placed in tight curlers, the follicle
eventually gives up and no longer is able to produce hair. This is often
accompanied by chemical alopecia, where the follicles have been injured
by frequent use of straighteners or relaxers. Applying a hot comb or
hot rollers, or using a heated iron without being careful, can also lead
to hair loss (hot comb alopecia: when the scalp is burnt by the
instrument or the melting petrolatum, or the hair shaft is weakened and
broken due to thermal injury).
TINEA CAPITIS: Also
known as ringworm, this is a fungal infection of the scalp, where the
hair breaks off, and there are scaling, crusted, reddened areas on the
scalp. With some fungal infections, bacteria co-infect these patches,
which then swell and are referred to as a kerion. This is usually a
condition of children and is rarely seen in adults.
