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Scalp Hair Disorders
1) Trichoschisis,
Trichoclasis, and
Trichoptilosis
2) Pohl-Pinkus Marks
3)
Monilethrix(Beaded
Hair)
4) Pseudomonilethrix
5) Pili
Torti(Twisted Hair)
6) Trichorrhexis
Invaginata(Bamboo
Hair)
7) Trichorrhexis
Nodosa
8) Menke`s Kinky
Hair Syndrome
9) Trichonodosis
10) Pilli
Annulati(Ringed
Hair)
11)
Trichothiodystrophy
Aside from
performing specific
blood tests and
scalp biopsy when
indicated, hair loss
diagnosis
encompasses a
systematic approach
consisting of a
directed history,
physical examination
of the scalp, and
specific clinical
assessments that can
be performed at the
time of the initial
consultation. One of
these assessments is
microscopic hair
shaft evaluation.
Although it is felt
by some that every
patient with a hair
complaint should
undergo a
microscopic hair
shaft examination,
it is clearly
indicated in cases
where hair breakage
or fragility is
suspected.
The technique
involves grasping a
group of 10-20 hairs
from an affected
area and cutting
them transversely
adjacent to the
scalp with a small
scissors. It is
suggested that both
short and long hairs
be chosen because
different lengths
along the shaft may
show a different
pathology. The
clipped hairs are
examined by 10 x
power light
microscopy.
Sometimes we use
polarizing lens to
reveal additional
findings.
Hair shaft anomalies
can be hereditary or
acquired. Some are
encountered as
isolated findings
while others are
associated with a
disease or syndrome.
Below is a brief
summary about these
anomalies for you to
become more
familiarize with
them.
1) Trichoschisis,
Trichoclasis, and
Trichoptilosis
These are different
types of fractures
of the hair shaft.
Trichoschisis
is a clean,
transverse fracture
through both the
hair shaft cuticle
and hair cortex.
Trichoclasis
is a transverse
fracture only
through the cortex
in which the hair is
held together by the
intact cuticle.
Trichoschisis and
Trichoclasis can be
caused by trauma and
are also seen in
trichothiodystrophy,
which will be
described later.
Both of these
conditions result in
very fragile hairs.
Trichoptilosis
is commonly known as
`Split ends` and
consists of
longitudinal
splitting or fraying
of the distal end of
the hair shafts. It
is generally seen
with long hair and
is caused by
excessive combing or
brushing, chemical
damage.
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2) Pohl-Pinkus Marks
Pohl-Pinkus Marks
represent zones of
decreased shaft
diameter or
constrictions. They
are secondary to
systemic diseases,
surgery, or
chemotherapy and can
be seen sometimes
after hair
transplantation.
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3)
Monilethrix(Beaded
Hair)
Monilethrix is
characterized by the
presence of altering
nodes with a medulla
and narrower,
internodal areas
without a medulla.
It is a congenital,
autosomal dominant
disorder that
presents with
alopecia of the
occipital region
which slowly extends
over the entire
scalp. The severity
of involvement
varies from
generalized to only
localized scalp
involvement. The
condition generally
improves with age.
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4) Pseudomonilethrix
Pseudomonilethrix is
an artifact caused
when pressure from
the microscopic
slides is applied on
two overlapping
hairs. A lateral
flattening of the
hair shaft occurs
that looks like a
node. When the
affected hair shaft
is rotated 90˚, the
node is seen as an
indentation caused
by pressure from the
overlapping hair.
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5) Pili
Torti(Twisted Hair)
In this disorder,
the hair shaft makes
irregular
longitudinal twists
along its long axis
rotating 90˚ to
360˚. The hairs are
flattened, brittle,
and break easily. It
can be seen as an
isolated congenital
anomaly or
associated with
other ectodermal
defects.
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6) Trichorrhexis
Invaginata(Bamboo
Hair)
In Trichorrhexis
Invaginata hairs are
short, thin, dull,
and friable.
Multiple nodules
along the hair shaft
are revealed under
the microscope. The
nodules resemble a
`ball and socket`
joint or the `joints
of a bamboo cane`.
Netherton`s syndrome
is composed of atopy,
ichthyosis (a
disorder of skin
keratinization), and
Trichorrhexis
Invaginata.
7) Trichorrhexis
Nodosa
This disorder is
usually produced by
trauma to the hair
shaft, either
physical (combing,
brushing, drying,
sun exposure) or
chemical. There are
also congenital
forms. The hairs
exhibit one or more
nodules that consist
a longitudinal
fracture along the
hair shaft with the
appearance of `two
broom whisks end to
end.
The affected hairs
are friable and
break at the nodes.
The chief complaint
is usually of having
observed `little
balls` in the hair
or that the hair
does not grow and
does not need to be
cut.
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8) Menke`s Kinky
Hair Syndrome
This syndrome is due
to a disorder in
intestinal
absorption and
intercellular
transfer of copper.
It is a sex-linked
recessive disorder
characterized by
kinky hair,
Trichorrhexis Nodosa,
Pilli Torti, and
fatal neurologic
abnormalities.
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9) Trichonodosis
Trichonodosis is
characterized by
spontaneous knotting
of the hair in
patients with curly
hair and is caused
by physical trauma.
The hair is short
due to fragility
with subsequent
fracture at the
knotted area.
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10) Pilli
Annulati(Ringed
Hair)
This defecit is seen
in hereditary forms
with variable
expression although
sporadic cases have
been reported. It
manifests during
infancy as hair with
alternating dark and
light bands without
fragility. The dark
bands are composed
of air bubbles in
the cuticle and
cortex that do not
permit transmitted
light to pass
through. Under
reflected light, the
colors reverse and
the dark bands
appear shiny.
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11)
Trichothiodystrophy
Trichothiodystrophy
is an autosomal
recessive disorder
characterized by
short, brittle,
ftattened hair of
low-sulfur content
and other
neuroectodermal
abnormalities. The
alopecia involves
the scalp, eyebrows,
and eyelashes. On
light microscopy,
the hairs have an
undulating, wavy
pattern with
Trichoschisis
fractures.
Examination under
polarized light
shows a
characteristic
`Tiger-Tail` or
alternating dark and
lighting pattern.
When evaluating a
patient with hair
fragility and
breakage, the hair
shaft disorders
should be kept in
mind as part of the
differential
diagnosis.
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