2. The
hair can be divided into three parts
(1) The bulb
A swelling at the base which originates
from the dermis
(2) The root
The hair lying beneath the skin surface
(3) The shaft
Which lies above the skin surface.
3.
4. In
cross-section,
(1) The medulla
An area in the core which contains loose
cells
and airspaces
(2) The cortex
Which contains densely packed keratin and
(3) The cuticle
Which is a single layer of cells arranged like
roof shingles.
5. Classification
Hairs
are classified into three main types
◦ Lanugo hair
◦ Vellus hair
◦ Terminal hair
Terminal
hairs convert to vellus hairs in male
pattern alopecia
Vellus hairs convert to terminal hairs in hirsutism.
6. Lanugo hair
Fine long hair
covering the foetus
Shed about 1
month before birth
unless born
prematurely.
May reappear
sometimes in
severe malnutrition
and anorexia
nervosa.
7. Vellus hair
Fine, short
unmedullated hair
covering much of
the body surface.
They replace the
lanugo hair just
before birth.
8. Terminal hair
Fully developed
Long coarse
medullated hair in the
scalp or pubic regions.
Their growth is
influenced by
circulating androgen
levels.
9. The hair cycle
Each
follicle passes through regular cycles of
growth and shedding.
There are three phases of follicular activity
◦ Anagen
The active phase of hair production.
◦ Catagen
A short phase of conversion from active growth to the
resting phase.
Growth stops, and the end of the hair becomes clubshaped.
◦ Telogen
A resting phase at the end of which the club hair is
shed.
10.
11. The
duration of each of these stages varies
from region to region.
On the scalp it is said to contain an average of
100,000 hairs
◦ Anagen lasts for upto 5 years
◦ Catagen for about 2 weeks
◦ Telogen for about 3 months
As
many as 100 hairs may be shed from the
normal scalp every day as a normal
consequence of cycling.
12.
13. Alopecia
The
term alopecia means loss
of hair
Alopecia has many causes and
patterns.
One convenient division is into
◦ Localized
◦ Diffused
It
is also important to decide if
the hair follicles are replaced by
scar tissue; if they have,
regrowth cannot occur.
16. Etiology
An
immunological basis is suspected because of an
association with
◦
◦
◦
◦
Autoimmune thyroid disease
Pernicious anemia
Vitiligo
Atopy
Histologically,
T lymphocytes cluster like a swarm of
bees around affected hair bulbs because cytokines
produced by the dermal papillae in lesions not only
attract lymphocytes to perifollicular region but also
stimulate them to multiply
17. Alopecia
areata is probably inherited as a
complex genetic trait
Sometimes
HLA-DQ3, -DR11 or -DR4 act as
susceptibility factors
◦ With an increased occurrence in the first-degree
relatives of affected subjects and twin concordance.
It
affects some 10% of patients with Down’s
syndrome, suggesting the involvement of genes
on chromosome 21.
Environmental
factors as well as emotional
factors may trigger alopecia areata in the
genetically predisposed.
19. Presentation
A
typical patch of hair loss area is uninflamed,
with no scaling, but with empty hair follicles
Pathognomonic
‘exclamation-mark’ hairs may be
seen around the edge of enlarging areas.
They
Are
are broken off about 4 mm from the scalp
narrowed and less pigmented proximally
20. Incidence
is most common in
the scalp and beard but
other areas, especially the
eyelashes and eyebrows, can
be affected too.
An
uncommon diffuse
pattern is recognized, with
exclamation-mark hairs
scattered widely over a
diffusely thinned scalp.
Up
to 50% of patients show
fine pitting or wrinkling of
the nails.
24. Course
The
outcome is unpredictable.
In a first attack, regrowth is usual within a few
months.
New hairs appear in the centre of patches as fine
pale down, and gradually regain their normal colour
The new hair may remain white in older patients.
Fifty percent of cases resolve spontaneously
without treatment within 1 year
Only 10% have severe chronic disease
Subsequent episodes tend to be more extensive
Regrowth is slower.
25. Hair
loss in some areas may coexist with regrowth
in others.
A
few of those who go on to have chronic disease
loose all the hair from their heads (alopecia
totalis) or from the whole skin surface (alopecia
universalis).
other variant is ophiasis which is lose of hair in a
band like patternat the periphery of scalp
Regrowth
is tiresomely erratic but the following
suggest a poor prognosis:
1. Onset before puberty
2. Association with Atopy or Down’s
syndrome
3. Unusually widespread alopecia and
4. Involvement of the scalp margin
type)
(ophiasiform
29. Treatment
A
patient with a first or minor attack can be
reassured about the prospects for regrowth.
Topical corticosteroid creams of high potency
can be prescribed
The use of systemic steroids should be avoided
in most cases
Intradermal injection of 0.2 ml intralesional
triamcinolone acetonide (5–10 mg/ml), raising a
small bleb within an affected patch, leads to
localized tufts of regrowth.
Side effects dermal atrophy evident as
depressed areas at the sites of injections.
30. Regrowth within a patch of alopecia areata after
a triamcinolone injection.
31. Ultraviolet
radiation or even psoralen
with ultraviolet A (PUVA) therapy may
help in extensive cases, but hair fall often
returns when treatment is stopped.
Contact sensitizers (e.g. diphencyprone)
seemed promising but the long-term
effect of persistent antigen stimulation is
worrying; they are still being used only in
a few centres under trial conditions.
Wigs are necessary for extensive cases.
32. A trial of diphencyprone to one side of the scalp
caused some regrowth
33. Androgenetic alopecia (malepattern baldness)
Cause
It
is because of miniaturization of hair follicles
Although
clearly familial, the exact mode of
inheritance has not yet been clarified.
Male-pattern
In
baldness is androgen dependent
females, androgenetic alopecia (female-pattern
hair loss), with circulating levels of androgen within
normal limits, is seen only in those who are strongly
predisposed genetically.
34. Presentation
The
common pattern in men is the loss
of hair first from the temples, and then
from the crown
However,
in women the hair loss may be
much more diffuse, particularly over the
crown
In
bald areas, terminal hairs are replaced
by finer vellus ones.
38. Complications
Anxiety
Bald
scalps burn easily in the sun
It has been suggested recently that bald
men are more likely to have a heart
attack and prostate cancer than those
with a full head of hair
41. Treatment
Scalp
surgery
Hair transplants
Wigs
Topical application of minoxidil lotion may slow early hair
loss and even stimulate new growth of hair but the results
are not dramatic
◦ Small and recently acquired patches respond best.
◦ When minoxidil treatment stops, the new hairs fall out
after about 3 months.
Antiandrogens help some women with the diffuse type of
androgenetic alopecia.
42. Treatment
Finasteride
(Propecia), an inhibitor of human type
II 5α-reductase, reduces serum and scalp skin
levels of dihydrotestosterone in balding men and
at the dosage of 1 mg/day, it may increase hair
counts
◦ Lead to a noticeable improvement in both frontal and
vertex hair thinning.
◦ However, the beneficial effects slowly reverse once
treatment has stopped.
◦ This treatment is not indicated in women or children.
Side-effects
are rare, but include
◦ Decreased libido, erectile dysfunction and altered
prostate-specific antigen levels
43. Telogen effluvium
All
the hair follicle are not synchronous
in their cycle
If anagen phase of several adjoining hair
follicles is aborted and these follicles
enter telogen phase at the same time and
several hair are shed simultaneously this
is called telogen effluvium
45. Clinical
features: hair loss occurs after 23mths after the precipitating factor
Severe cases associated with anemia and
beau’s lines of the nails.
Treatment: stops spontaneously after23mths
47. Hirsutism and hypertrichosis
Hirsutism
is the growth of terminal hair in a
woman which is distributed in a pattern
normally seen in a man (for example,
mustache, beard, central chest, shoulders,
lower abdomen, back, and inner thighs).
Hypertrichosis
is an excessive growth of
terminal hair in either sex that does not
follow an androgen-induced pattern
48. Types of hypertrichosis
Congenital
Hypertrichosis is very rare.
◦ A fetus is covered with lanugo and it does not fall
off but continues to grow.
Acquired
Hypertrichosis
◦ Occurs after birth.
◦ Unpigmented vellus hair or pigmented terminal
hair.
◦ The excessive hair may cover the entire body
(Generalized), or it could be localized to one
area.
52. Causes of hypertrichosis
Generalized
Anorexia nervosa, starving, malnutrition
Drug induced- minoxidil, diazoxide, ciclosporin
anabolic steroids.
porphyrias
Fetal alcohol syndrome
Fetal phenytoin syndrome
Hypertrichosis lanuginosa(congenital or acpuired)
General systemic illness (such as advanced HIV infection)
Hypothyroidism or other endocrine disorders
53. Hirsutism
Cause
Increased level of androgens or an oversensitivity of hair follicles to androgens
Racial or familial trait (Mediterranean, Caucasians and Asians)
Idiopathic hirsutism
Hormonal:
Polycystic Ovarian Syndrome
Cushing's disease
Tumors in the ovaries or adrenal gland
Congenital adrenal hyperplasia
postmenopausal women
Itragenic:
Drugs- androgens or progesterones, anabolic steroids.
54.
55. Presentation
An
in
◦
◦
◦
◦
◦
◦
◦
excessive growth of hair
Beard area and side burn
Chest
Shoulder-tips
Around the nipples
Abdomen
Male pattern of pubic hair
Androgenetic alopecia
Signs
◦
◦
◦
◦
◦
◦
◦
of virilization
Temporal hair recession
Acne
Deep voice, increased size of Adam's apple
Oily perspiration
Breast atrophy
Muscle hypertrophy
Loss of female body contour
56.
57.
58. Investigations
Significant
hormonal abnormalities are not usually found in
patients with a normal menstrual cycle.
Investigations
◦
◦
◦
◦
are needed if:
Hirsutism occurs in childhood
There are features of virilization
Hirsutism is of sudden or recent onset
There is menstrual irregularity or cessation
59. The tests sent are
Total and free testosterone
Sex hormone binding globulin
Free androgen index
Dihydroxyepiandrosterone sulfate
Androstenedione (drawn after 10 a.m.)
If there is also menstrual disorder, additional tests may be requested.
◦ Luteinizing hormone (LH) and follicle stimulating hormone (FSH)
◦ Oestradiol, 17-hydroxy progesterone
◦ Prolactin
Tests may be requested to evaluate other related aspects of health, for
example:
◦ Thyroid function
◦ Cortisol or overnight dexamethasone test
◦ Glucose
◦ Lipids (cholesterol and triglyceride)
Pelvic ultrasounds
60. Treatment
Treat
underlying disorder
Home remedies for minor hirsutism include
commercial, waxing or shaving, or making its
appearance less obvious by bleaching
Plucking should be avoided as it can stimulate hair
roots into Anagen.
The abnormally active follicles can be destroyed by
electrolysis.
If numerous, by laser
Topical therapy with eflornithine, an inhibitor of
ornithine decarboxylase, can slow regrowth.
61. Oral
antiandrogens
◦ Oral contraceptive pills with oestrogen and
cyproterone- antiandrogenic activity
◦ Cyproterone acetate 50-200 mg for 10 days
each cycle
◦ Spironolactone 50-200 mg daily can slowly
reduce excessive hair growth-long term.
Pregnancy
must be avoided during such
treatment as it carries the risk of feminizing
a male fetus.