Disorders of pigmentation — Part 2: Hypopigmentation

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INSIDE
General approach
Vitiligo
Infective causes
Other acquired
disorders
Genetic and
congenital
disorders
the authors
Dr Deepani Rathnayake
consultant dermatologist, Base
Hospital Dambulla, Sri Lanka.
Background
DISORDERS of pigmentation are
a common presentation in dermatology and general practice. Part 1
of this update on disorders of pigmentation outlined the physiology
of skin pigmentation and the pathological mechanisms that lead to
these disorders. It then discussed the
general approach to pigmentary disorders and focused on the diagnosis
and management of hyperpigmentary disorders.
Hypopigmentation, like hyperpigmentation, can lead to significant psychosocial problems. It can
even be a reason for social rejection. This is especially pertinent in
the cosmetic management of the
hypopigmented lesions that can be
significantly disfiguring on the face
and other exposed skin. Acquired
hypopigmentation may be associated with an underlying systemic
disorder that may be treatable. The
search and treatment for underlying
conditions are just as important as
the management of the presenting
cosmetic complaint.
This article discusses the general
approach to hypopigmented skin
lesions and then specific hypopigmentary conditions in more detail.
cont’d next page
Disorders of
pigmentation
— Part 2:
Hypopigmentation
Professor Rod Sinclair
director and head, dermatology,
Epworth Hospital, Melbourne,
Victoria.
This is the second of a two-part series on disorders of pigmentation. Part 2 covers hypopigmentary
disorders in detail.
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18 April 2014 | Australian Doctor |
23
How To Treat – Disorders of pigmentation— Part 2: Hypopigmentation
General approach
HYPOPIGMENTARY disorders
may be due to both genetic and
acquired causes. The pathogenic
mechanisms by which hypopigmentation occurs can be broadly
divided into two processes:
• Reduced or absent melanocytes;
or
• Reduced number of melanosomes and melanin in the skin
(table 1).
The use of a
Wood’s lamp can
considerably improve
the diagnosis of
hypopigmentary
lesions, especially in
patients with lighter
skin colour.
Figure 1:
Hypopigmentation
in a patient with
systemic sclerosis
on the extensor
surface of the right
elbow.
Diagnosis
Most hypopigmentary disorders
can be diagnosed with a detailed
history and examination. A hypopigmented lesion present at birth
may be a naevus or an ash-leaf
macule. A history of a preceding
skin rash favours the diagnosis of
post-inflammatory hypopigmentation. The presence of anaesthesia
in a hypopigmented lesion is an
important clue in a clinical diagnosis of leprosy. Additional investigations are necessary if the diagnosis
cannot be confirmed on clinical
grounds alone. A skin biopsy will
be useful in some patients.
Idiopathic guttate hypomelanosis
is often misdiagnosed and treated as
pityriasis versicolor. The distinction
may be better elucidated by taking
scrapings from the skin lesions in
question. Scrapings from a lesion of
pityriasis versicolor typically have a
‘spaghetti and meatballs’ appearance
under the microscope after dissolving in 30% potassium hydroxide on
a glass slide.
As mentioned in Part 1, the use
of a Wood’s lamp can considerably improve the diagnosis of
hypopigmentary lesions, especially
in patients with lighter skin colour
(table 2). The features found under
Table 1: Pathogenic mechanism in hypopigmentary disorders
Disease
Defect
Piebaldism
Congenital absence of melanocytes
Vitiligo, discoid lupus erythematosus,
systemic sclerosis (figure 1)
Acquired destruction of melanocytes
Albinism, phenylketonuria, drugs (eg,
skin-whitening creams)
Reduced melanin production
Tuberous sclerosis
Reduced melanosome transfer to
keratinocytes
Post inflammatory hypopigmentation
due to psoriasis
Increased melanin and keratinocyte
turnover
Table 2: Wood’s lamp features in hypopigmentary disorders
Hypopigmentary disorder
Features under Wood’s lamp
Pityriasis versicolor
Yellow to yellow-green fluorescence
Vitiligo
Bright areas with sharp borders varying in
location and extent
Tuberous sclerosis
Patches; characteristic ash-leaf shape
Hypomelanosis of Ito
Whorled or streaked patterns.
Naevus anaemicus
Lesion becomes inapparent
Hypochromic naevi
Off-white accentuation
Wood’s lamp examination on
hypopigmented lesions are shown
in the table below left.
General principles of
management
Cosmetic camouflage is an important part of managing hypopigmented skin lesions.
It is important to emphasise
to the patient that, somewhat
counter-intuitively, tanning worsens the cosmetic appearance of
hypopigmented lesions on fair or
light skin. It makes the contrast
between normal and depigmented
skin more noticeable.
Furthermore, depigmented skin
has a higher risk for chronic sun
damage and skin cancer. This risk
of sun damage is heightened in a
country such as Australia where
there are long hours of intense
sun. A broad-spectrum sunscreen
with both UVB and UVA protection helps resist tanning with additional protection against chronic
sun damage.
Vitiligo
VITILIGO is an acquired pigmentary disorder of the skin and
mucous membranes presenting
with well-demarcated depigmented macules of varying sizes
and shapes. Depending on the
clinical presentation and distribution, vitiligo can be classified as localised or generalised.
Localised disease can be further
classified as focal (one or more
macules), segmental (macules in
a dermatomal distribution) and
mucosal (mucous membranes
alone). Generalised vitiligo can
be acrofacial (distal fingers and
periorificial
areas),
vulgaris
(scattered widely distributed
patches) or mixed. Universal
vitiligo refers to extensive and
almost complete depigmentation
of the whole body.
Pathogenesis
There are several theories for the
pathogenesis of vitiligo. Genetic
factors may play a role and a positive family history is seen in some
patients. There is an absence of
melanocytes in the lesions, which
is due to the destruction of melanocytes. Autoimmune mechanisms, cytotoxic mechanisms,
intrinsic defect of melanocytes,
oxidant-antioxidant
mechanisms, and neural mechanisms are
thought to contribute to the mel-
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| Australian Doctor | 18 April 2014
Table 3: Classification of hypopigmentation/depigmentation
disorders — genetic causes
Figure 2: Large anaesthetic hypopigmented macular lesion with raised borders
due to leprosy.
anocyte destruction. Vitiligo may
be associated with other autoimmune disorders.
Diagnosis
Vitiligo is a clinical diagnosis.
Patients may present with progressive depigmentation of the skin. The
rate of progression is variable. Usually there is complete depigmentation in the lesions but in trichrome
vitiligo a mixture of complete and
partial pigmentary loss can be
seen. There may be associated leukotrichia. The lesions may appear
at sites of trauma from Koebner’s
phenomenon and this usually indicates an active disease.
Differentiating vitiligo from
other hypopigmented lesions can
be difficult sometimes and certain
specific features should be looked
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Extent of disorder
Possible causes
Localised
Piebaldism
Waardenburg syndrome
Ziprkowski–Margolis syndrome
Hypomelanosis of Ito and mosaicism
Focal dermal hypoplasia
Naevus depigmentosus
Tuberous sclerosis complex
Incontinentia pigmenti
Generalised
Albinism
Albinoid disorders (Chédiak–Higashi syndrome,
Griscelli syndrome, Prader–Willi syndrome,
phenylketonuria, homocystinuria)
for (tables 3 and 4). For example:
• Pityriasis alba has an ill-defined
border with slight scaling, usually seen on the face in children.
• Pityriasis versicolor has coalescing macules with slight scaling. It
is seen as yellow to yellow-green
under a Wood’s lamp.
• Hypopigmented mycosis fungoides has skin atrophy and illdefined lesions.
• Lichen sclerosus et atrophicus
has guttate hypopigmentation
with skin sclerosis.
• Leprosy has features of anaesthesia, and has raised borders
(figure 2).
Treatment
Treatment of vitiligo can often
be
unsatisfactory.
Complete
repigmentation is unlikely in
most patients and recurrences
are common. Treatment should
depend on the individual. Patients
should be properly counselled
about the treatment outcome and
side effects. Cosmetic disfigurement is the main reason for treatment especially in darker skin
types. Non-treatment is an option
in skin type 1 and 2.
Topical therapies are suitable
for patients with few lesions.
Topical steroid preparations are
commonly used as first-line therapy in localised vitiligo. They
are moderately successful, but
long-term application can cause
cont’d page 26
How To Treat – Disorders of pigmentation— Part 2: Hypopigmentation
from page 24
skin atrophy. Topical tacrolimus ointment (0.03% or 0.1%)
is an effective alternative, particularly when the disease involves
the head and neck. It can also be
combined with laser and phototherapy. Vitamin D analogs, calcipotriol and tacalcitol have been
used as topical therapeutic agents
immune-modulating agents for
the treatment of vitiligo.
Narrow-band UVB phototherapy is commonly used and can be
safely used in children and pregnant or lactating women. Psoralen
photochemotherapy is a good
option in patients with widespread
disease. Psoralens can be given
either topically or orally, followed
by exposure to artificial UV light
or natural sunlight. Post-treatment
eye protection with UV protective
sun glasses is necessary. Lesions
on the face and trunk usually
respond well while lesions on the
dorsal surface of the hands show
resistance to treatment. Prolonged
treatment over many months is
required before repigmentation
appears.
Systemic oral steroid (prednisone) is an option in patients
with rapidly progressive disease.
Weekly pulses or lowest effective
doses can be given to minimise
the side effects. Once the disease
is stable it would be desirable to
change to phototherapy to induce
repigmentation.
Depigmentation therapy
Depigmentation therapy will be
an option if vitiligo is widespread
and repigmentation treatment is
Table 4: Classification of hypopigmentation/depigmentation
disorders — acquired causes
Type of
disorder
Acquired causes
Autoimmune
Vitiligo, Vogt–Kayonagi syndrome, systemic sclerosis,
discoid lupus erythematosus
Metabolic and
nutritional
Kwashiorkor
Iron deficiency
Vitamin B12 deficiency
Hypopituitarism
Hypogonadism
Cushing’s
Chemical/drugs
Liquid nitrogen, steroid (topical, intralesional, intra-articular)
Bleaching creams
Infections
Leprosy
Pityriasis versicolor
Syphilis
Post
inflammatory
Psoriasis
Pityriasis alba
Atopic dermatitis
Pityriasis lichenoides chronica (figure 3)
Melanocytic
tumours/
malignancies
Halo naevus
Melanoma-associated
Mycosis fungoides
Other
Idiopathic guttate hypomelanosis
Progressive macular hypomelanosis
Leucoderma punctata
Lichen sclerosus et atrophicus
unlikely to produce acceptable
results. Monobenzyl ether of
hydroquinone is used to achieve
permanent depigmentation. As
the depigmentation is permanent,
proper counselling is necessary.
The patient should be started on
appropriate sun protection methods to minimise sun damage of
totally depigmented skin.
Surgery
Surgical skin-grafting treatments
Figure 3:
Multiple small
depigmented
lesions on the
trunk after
resolution of the
inflammatory
changes
associated
with pityriasis
lichenoides
chronica.
A
should be considered in stable
localised disease and is a good
option in patients with segmental vitiligo. Even in very stable
disease, depigmentation of the
grafts can occur. Suction epidermal grafting, thin dermoepidermal grafts, noncultured epidermal
suspensions, cultured melanocyte
suspensions and punch minigrafting (figure 4) are some methods
that show cosmetically acceptable
results.
B
Figure 4: A: Test
grafts by mini
punch grafting
for localised
stable vitiligo
of the lower lip
to reintroduce
colour to a patch
of vitiligo. B: Test
grafts by mini
punch grafting
for localised
stable vitiligo
starting to show
repigmentation
on a follow-up
visit.
Infective causes
THERE are several infections
that may cause hypopigmentation such as pityriasis versicolor
and leprosy. Other infective causes
include syphilis, other treponematoses and onchocerciasis.
A
Pityriasis versicolor
Pityriasis versicolor, or tinea versicolor, can either be hypopigmented or hyperpigmented (figure
5). It is proposed that the hypopigmentation occurs as a result of the
inhibition of tyrosinase by dicarboxylic acids formed by Malassezia furfur. The patients often
describe poor tanning of lesions.
Figure 5:
A: Pityriasis
versicolor on
the left upper
trunk showing
hypopigmented
macular lesions.
B: Pityriasis
versicolor on the
thigh showing
hyperpigmented
macular lesions.
B
Clinical features
The pityriasis versicolor lesions
are well-demarcated oval to round
macules commonly seen coalescing to form irregularly shaped
patches. There are fine dust-like
scales covering the lesions. Wood’s
lamp examination shows yellowish-white or copper-orange fluorescence (table 2).
Treatment
Various agents can be used to treat
pityriasis versicolor. Selenium
sulfide, sodium sulfacetamide,
ciclopiroxolamine, azole and
allylamine antifungals have been
used with success.
There are different topical regimens. Selenium sulfide lotion is
applied daily for two weeks to
affected areas and washed off after
10 minutes. Leaving the applica-
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| Australian Doctor | 18 April 2014
to the increased risk of liver toxicity.
Recurrences can be common
even with oral therapy. Hypopigmentation may persist after successful treatment and sometimes
take months to resolve.
Leprosy
tion on overnight can be helpful in
resistant cases. Topical azole antifungals can be applied every night
for two weeks. Subsequent weekly
applications of any of the topical
agents for a few months may help
prevent recurrence.
In patients with widespread
disease oral antifungal therapy
is more convenient and effective.
Ketoconazole, fluconazole and
itraconazole are all effective and
there are different dosing regimens. However, the side effects of
oral therapy should be discussed
with the patient. Fluconazole
150-300mg weekly for 2-4 weeks
or itraconazole 200 mg daily for
seven days are used in extensive
and resistant cases. Ketoconazole
200mg daily for 10 days is also
effective but its use is limited due
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Even though it is rare in Australia,
leprosy should be suspected in
patients who have migrated from
endemic countries and present
with persistent hypopigmented
lesions. The initial lesion is a
sharply demarcated oval or round
hypopigmented macules with dry
scaly centre and erythematous
borders. Localised anaesthesia and
thickened cutaneous nerves give
clues to the diagnosis.
Even though it is
rare in Australia,
leprosy should be
suspected in patients
who have migrated
from endemic
countries and present
with persistent
hypopigmented
lesions.
cont’d page 28
How To Treat – Disorders of pigmentation— Part 2: Hypopigmentation
Other acquired disorders
Vogt–Koyanagi–Harada
syndrome
Figure 6: Guttate
hypopigmented
macules on the
shin.
VOGT–Koyanagi–Harada
syndrome is a rare disease with a presumed autoimmune aetiology. It
is characterised by chronic, bilateral granulomatous uveitis with
dermatological, neurological and
auditory involvement. The disease
has four stages:
• The prodromal stage, where the
patient has flu-like symptoms
with headache, nausea, meningism, auditory discomfort and
tinnitus.
• Acute uveitic stage. In this stage
there is onset of blurring of
vision in both eyes and bilateral
granulomatous anterior uveitis.
• Convalescent
stage,
which
occurs several weeks later with
skin changes including vitiligo,
alopecia and poliosis.
• The chronic recurrent stage,
where the patient may subsequently experience repeated
bouts of uveitis.
Early diagnosis and steroid
therapy help to reduce the complications and recurrent attacks.
Long-term ophthalmological monitoring is necessary. Skin depigmentation is treated the same way
as vitiligo.
Post-inflammatory
hypopigmentation
Figure 7:
Pityriasis alba
lesions on the
face of a child.
Idiopathic guttate hypomelanosis is a benign hypopigmentation
disorder of unknown aetiology. It
is commonly seen in middle-aged
women. The lesions are typically
seen on the anterior lower legs
initially and gradually spread into
the sun-exposed areas (figure 6).
The lesions are hypopigmented
or depigmented, discrete, angular
or circular macules of 1-3 mm in
diameter. Treatment is mainly
for cosmetic reasons. Topical or
intralesional corticosteroids, retinoids, pimecrolimus have shown
variable results. Surgical treatments with trichloroacetic acid,
cryosurgery and dermabrasion
have some success. Fractional carbon dioxide laser has been a safe
and effective treatment.
Figure 8:
Depigmentation
on the wrist
following intraarticular steroid
injection for
de Quervain’s
tenosynovitis.
Progressive macular
hypomelanosis
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| Australian Doctor | 18 April 2014
Post-inflammatory hypopigmentation is more noticeable in darkskinned individuals and can be the
consequence of both primary cutaneous conditions and secondary to
therapeutic interventions. These
may include seborrhoeic dermatitis, pityriasis versicolor, pityriasis lichenoides, atopic dermatitis,
psoriasis, lichen planus, lichen
striatus, cryotherapy, and intralesional and intra-articular steroid
injections (figure 8). The hypopigmentation is attributed to a loss
of functional melanocytes due to
the inflammation. Repigmentation can take weeks to months.
The underlying disease should be
treated. Cosmetic camouflage can
be maintained until repigmentation occurs.
Halo naevus
Idiopathic guttate hypomelanosis
Progressive macular hypomelanosis is an uncommon disease in
Australia but can be commonly
seen in patients with skin types
IV-VI. The condition is often
misdiagnosed and treated as for
pityriasis versicolor. It is a disease
of young adults presenting with
ill-defined asymptomatic hypopigmented macules on the trunk.
The lesions spread slowly and
coalesce in and around the midline. They are more commonly
seen on the back and can spread
to the abdomen. In contrast to
pityriasis versicolor, progressive
macular hypomelanosis does not
show scaling. Propionibacterium
acnes causing depigmentation has
been suggested as the causative
factor.
Currently 1% clindamycin
lotion during the daytime, 5%
benzoyl peroxide gel at night-time
is commonly used. UVA, UVB
or even natural sunlight hastens
repigmentation. Recurrences can
occur when treatment stops.
Pityriasis alba usually resolves
spontaneously. Low-potency topical steroids may help with erythema and pruritus.
Figure 9: Halo
naevi on the
right jaw.
Pityriasis alba
Pityriasis alba is more commonly
seen in children and young adults.
The disease is characterised by illdefined irregular hypopigmented
patches with scaling and mild
erythema. There can be multiple
lesions on the face (figure 7). The
upper arms, neck, or shoulders
may also be involved. Pruritus
may be a clinical feature. Pityriasis
versicolor, vitiligo, leprosy, hypowww.australiandoctor.com.au
pigmented mycosis fungoides,
nummular eczema and pityriasis
rosea on the face may all mimic
pityriasis alba. Atopy and excessive sun exposure can predispose
the development of these lesions.
Halo naevus is also known as
‘Sutton naevus’. It is a mole with
a white ring, or ‘halo’, around it
(figure 9). They are more common
in children and young adults. They
are also seen more commonly in
people with multiple melanocytic
naevi.
The halo naevus has a characteristic progression. A halo appears
around a pre-existing melanocytic naevus and the naevus then
disappears gradually. It leaves a
hypopigmented macule that takes
months to repigment. It is considered an autoimmune process. For
unknown reasons the body reacts
against certain moles and make
them disappear. Usually these
moles are benign. However, all
halo moles need to be examined
carefully by a medical practitioner
because malignant melanomas can
have this halo phenomenon. Apart
from the exclusion of a melanoma
and patient reassurance, a halo
mole itself does not require treatment.
Hypopigmented mycosis
fungoides
Hypopigmented mycosis fungoides is an atypical, unique variant of mycosis fungoides usually
observed in dark-skinned individuals. It is characterised by gradually progressive hypopigmented
macules and patches with skin
atrophy. The lesions are commonly seen in the trunk. Pruritus
may be a clinical feature. Hypopigmented mycosis fungoides
should be included in the differential diagnosis of any persistent
hypopigmented macule or patch
that is resistant to treatment.
Multiple skin biopsies are usually done to obtain a histological
diagnosis and sometimes repeated
biopsies after a few months will be
needed if the diagnosis remains in
doubt. Most cases have a benign
course but follow-up of these
patients will be necessary to detect
recurrences.
Hypopigmented
mycosis fungoides responds well
to UVA and UVB, resulting in
long-term remission.
Lichen sclerosus
Lichen sclerosus, or lichen sclerosus et atrophicus, is a chronic
inflammatory dermatosis of the
skin presenting as white plaques
with epidermal atrophy, scarring
and skin sclerosis. Lichen sclerosus
has both genital and extragenital
presentations. Extragenital lichen
sclerosus is usually asymptomatic
(figure 10). Vulvar lichen sclerosus usually presents with atrophic
hypopigmented lesion, pruritus,
dyspareunia, dysuria or genital
bleeding. Penile lichen sclerosus is
usually pruritic and the skin sclerosis later results in phimosis.
Lichen sclerosus in the skin usually starts as white papules that
coalesce into plaques. On the
Asymptomatic
extragenital lichen
sclerosus usually
does not require any
treatment.
Figure 10:
Extragenital
lichen
sclerosus
showing
guttate
hypopigmented
atrophic
plaques in the
trunk.
surface of the plaque there are
comedo-like plugs and telangiectasia that may be easily identified
with dermoscopy and is a useful
clue to differentiate it from other
hypopigmented lesions. With time,
the plugs will disappear and leave
a smooth, porcelain-white plaque.
The size of the lesions can range
from a few millimetres to very
large areas. A skin biopsy can confirm the clinical diagnosis.
Asymptomatic
extragenital
lichen sclerosus usually does not
require any treatment. Superpotent topical steroids, topical
testosterone, topical retinoids,
tacrolimus and pimecrolimus have
proven useful in treating female
genital lichen sclerosus.
Genetic and congenital disorders
Albinism
ALBINISM is a group of inherited
disorders of melanin synthesis and
is characterised by a congenital
reduction or absence of melanin
pigment in the skin, hair and eyes.
There are two types of albinism:
ocular cutaneous albinism and
ocular albinism. Ocular albinism
only affects the optic system and
does not affect the skin and hair
colour.
In ocular cutaneous albinism,
there is a reduction or absence of
melanin in the skin, hair and eyes.
The lack of skin pigment results
in a pale skin appearance and an
increased risk of skin cancer. Ocular cutaneous albinism is divided
further into several subtypes based
on the genetic mutation. Chédiak–
Higashi syndrome is a rare autosomal recessive disorder that has an
immunodeficiency associated with
ocular cutaneous albinism.
Patients with ocular cutaneous albinism should be advised
to apply broad-spectrum sunscreens with an SPF of at least 30,
together with other methods that
prevent sun exposure. Eyes should
be protected by wearing dark, UVblocking sunglasses. They should
be referred to an ophthalmologist
and regularly screened for skin
cancers.
Piebaldism
Piebaldism is a rare autosomal
dominant disorder caused by the
congenital absence of melanocytes. The patient typically presents with white forelock and
Figure 11:
A baby with
hypomelanosis
of Ito on the
trunk.
tion. Treatment is not required for
naevus anaemicus. Camouflage
makeup may help cover the lesion.
Achromic naevus (naevus
depigmentosus)
Achromic naevus is usually a solitary
hypopigmented macule seen from
birth or early childhood. The lesions
are well defined with irregular borders resembling a splash of paint.
Achromic naevus appears offwhite on Wood’s lamp examination. Excimer laser, phototherapy
and skin grafting have been tried
for the treatment but reassurance
is generally adequate.
Tuberous sclerosis
Patients with ocular
cutaneous albinism
should be referred to
an ophthalmologist
and regularly
screened for skin
cancers.
multiple symmetrical hypopigmented or depigmented macules.
The lesions are commonly seen on
the face; the trunk and extremities are also involved. The skin
lesions can mimic vitiligo. Piebaldism is a benign disorder. However,
patients are at risk for actinic damage. Cosmetic camouflage and sun
protection are important aspects
in the management. Skin grafts
are effective and stable. Piebaldism is one of the cutaneous signs
of Waardenburg syndrome, along
with heterochromia of the irides,
lateral displacement of inner canthi, and deafness.
Naevus anaemicus
Naevus anaemicus is a congenital vascular anomaly presenting
as a hypopigmented macule or
patch since birth that grows with
the child. It is a pale macule with
irregular margins and persists
throughout life. Diascopy helps
to differentiate naevus anaemicus
from vitiligo and hypochromic
naevi. This test involves applying pressure on a skin lesion with
a glass slide and observing for
a colour change. When applied
to naevus anaemicus it becomes
indistinguishable from the surrounding skin as the surrounding
skin is blanched with pressure.
Wood’s lamp examination does
not accentuate naevus anaemicus
and may make the lesion inapparent, whereas in vitiligo the lesions
become prominent and hypochromic nevi show off-white accentua-
Tuberous sclerosis or tuberous
sclerosis complex is a neurocutaneous disorder that causes hamartomas in various organs including
the skin. Ash-leaf hypopigmented
macules are usually the only lesion
seen at birth. Ash-leaf macules can
be multiple and become prominent
when examined under Wood’s
lamp.
Hypomelanosis of Ito
Hypomelanosis of Ito presents as
hypopigmented whorls of skin
along the Blaschko lines (figure 11)
and can be associated with neurological, skeletal, hair and dental
defects. The skin lesions present
from birth and are asymptomatic.
Hypopigmented macules along the
lines of Blaschko are seen sometimes involving more than one
dermatome. Wood’s lamp examination enhances the pattern.
Case study
DILAN, a 21-year-old medical
student, was referred by his GP to
the dermatology clinic with hypopigmented lesions on the trunk for
over six months. His mother had
noted the lesions first when they
were on his back. These were then
observed to spread towards the
shoulders and the lateral abdomen. There is no itching or any
other symptoms associated with
the lesions. He had had the lesions
for over two months before he presented to the GP.
The GP gave him topical 2%
ketoconazole cream to be applied
twice a day for four weeks. The
Figure 12:
Progressive
macular
hypomelanosis
on the back with
hypopigmented
macular lesions
coalescing in
and around the
midline.
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lesions spread despite the treatment and he had not applied any
further treatment over the past
two months.
Dilan was worried because the
lesions were spreading, and he
was ashamed to take his shirt off
to swim.
On examination, there were
hypopigmented
macules
on
the back, shoulders and lateral
abdominal wall. The lesions coalesced at the midline, forming large
macules. There was no visible scaling (figure 12). The lesions were
not anaesthetic. Scrapings from
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How To Treat – Disorders of pigmentation— Part 2: Hypopigmentation
from previous page
the lesions for pityriasis versicolor
were negative.
A diagnosis of progressive macular hypomelanosis was made. The
benign nature of the condition was
explained to Dilan. He was started
on 1% clindamycin gel in the morning and 5% benzoyl peroxide gel at
night to be continued for 4-8 weeks.
Dilan was advised to expose the
lesions to natural sunlight around
10-11am for 10-15 minutes so that
he could hasten repigmentation of
the lesions. He had a good response
after four weeks but he was asked to
continue the treatments for another
four.
Progressive macular hypomelanosis is a benign condition but its
appearance and progressive nature
cause distress in affected patients.
Careful examination of its distribution on the back — with the lesions
coalescing in the midline, an absence
of any scaling, and a slowly progressive nature towards the anterior
abdominal wall — helps to differentiate it from many similar hypopigmented lesions.
Dilan was advised
to expose the lesions
to natural sunlight
around 10-11am for
10-15 minutes so
that he could hasten
repigmentation of the
lesions.
3. Which TWO statements are correct
regarding the clinical features and
diagnosis of vitiligo?
a) A skin biopsy is necessary to confidently
diagnose vitiligo
b) Vitiligo lesions may not be completely
depigmented
HYPOPIGMENTATION
disorders, while often not as cosmetically common in Australia as
hyperpigmentary disorder, may
cause as much psychological distress to the patient as hyperpigmentary disorders. Some of the
hypopigmentary disorders will
also be associated with an underlying systemic disease and a reasonable level of suspicion is required
to pick up acquired causes of
hypopigmentation such as hormonal disorders and vitamin deficiencies. A thorough history and
clinical examination will guide
appropriate investigations and
prompt referral to the specialist if
it is required. It should be remembered that regardless of whether
the underlying cause is able to be
cured, cosmetic camouflage, sun
protection and psychosocial support are important principles in the
management of these conditions.
eMedicine
www.emedicine.com/derm/
DermNet NZ
dermnetnz.org
Further reading
1. Wolff K, et al. Fitzpatrick’s
Dermatology in General Medicine.
7th edn. McGraw-Hill Inc, New
York, 2007.
2. James WD, et al. Andrews’
Diseases of The Skin: Clinical
Dermatology. 11th edn. Elsevier
Inc., Edinburgh, 2011.
3. Burns T, et al. Rook’s Textbook
of Dermatology. 8th edn. WileyBlackwell, Hoboken NJ, 2010.
References
Available on request from
[email protected]
Complete this quiz online and fill in the GP evaluation form to earn 2 CPD or PDP points.
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Disorders of pigmentation— Part 2:
Hypopigmentation — 18 April 2014
2. Which THREE statements are correct
regarding the Wood’s lamp features of
hypopigmentary disorders?
a) Wood’s lamp examination of pityriasis
versicolor shows dark areas with silver
borders
b) Wood’s lamp examination of vitiligo shows
bright areas with sharp borders
c) Wood’s lamp examination of hypochromic
naevi shows off-white accentuation
d) Naevus anaemicus under the Wood’s lamp
becomes inapparent
Online resources
Instructions
How to Treat Quiz
1. Which TWO statements are correct
regarding the general approach to and
management of skin hypopigmentation?
a) History of a preceding rash or anaesthesia
over a hypopigmented lesion can both point
to a diagnosis
b) Skin scrapings for mycology are not useful in
the diagnosis of skin hypopigmentation
c) Sunscreens should not be applied
to depigmented skin lesions to avoid
exacerbating the problem
d) Cosmetic camouflage can aid management of
hypopigmented skin lesions
Conclusion
c) Vitiligo is indistinguishable from lichen
sclerosus
d) Vitiligo patches that appear at sites of trauma
indicates an active disease
4. Which TWO statements are correct
regarding the treatment of vitiligo?
a) Vitiligo should be treated with weekly highdose prednisone orally until repigmentation
occurs
b) Surgery with skin grafts may be a good option
for stable segmental vitiligo
c) Depigmentation therapy is used for small
areas of localised vitiligo
d) Phototherapy for repigmentation of vitiligo
requires treatment over many months
5. Which TWO statements are correct
regarding the diagnosis and management
of pityriasis versicolor and other infective
causes of hypopigmentation?
a) Lesions of pityriasis versicolor are usually
covered by fine dust-like scales
b) Hypopigmentation generally clears
immediately after successful treatment of the
underlying infective cause
c) Other infections that may causes skin
hypopigmentation include syphilis and
onchocerciasis
d) Oral ketoconazole is safe and may be given
for a few months to prevent recurrence of
pityriasis versicolor
6. Which TWO statements are correct
The mark required to obtain points is 80%. Please note that some questions have more than one correct answer.
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regarding the clinical features of acquired
hypopigmentary disorders?
a) Vogt-Koyanagi–Harada syndrome presents
initially like a flu with uveitis
b) Idiopathic guttate hypomelanosis is
commonly seen on the anterior lower legs of
middle-aged women
c) Genital lichen sclerosus usually presents
with asymptomatic atrophic hypopigmented
lesions
d) Hypopigmented mycosis fungoides is usually
a clinical diagnosis based on asymptomatic
persistent hypopigmentation on the digital
webs
7. Which TWO statements are correct
regarding the management of acquired
hypopigmentary disorders?
a) Apart from reassurance a halo naevus does
not require further management
b) Pityriasis alba is self-limiting and usually
resolves spontaneously
c) Asymptomatic extragenital lichen sclerosus
usually does not require any treatment
d) Cosmetics should not be applied to postinflammatory hypopigmentation
8. Which TWO statements are correct
regarding genetic or congenital causes of
hypopigmentation?
a) Skin lesions in hypomelanosis of Ito develop
along the lines of Blaschko
b) Naevus anaemicus becomes erythematous
on diascopy
c) Achromic naevus lesions resemble a splash
of paint
d) Hypopigmented lesions in tuberous sclerosis
usually present as large papulotubercles
9. Joshua is a 56-year-old man who returned
recently from India after a six-month
medical mission. He had developed several
pruritic hypopigmented lesions on his
trunk. Which TWO statements are correct
regarding his assessment and diagnosis?
a) Skin atrophy and ill-defined lesions may point
to hypopigmented mycosis fungoides
b) Leprosy may be diagnosed clinically based on
the history of a prolonged stay in an endemic
area
c) Dermoscopic findings of comedo-like plugs
and telangiectasia may suggest the diagnosis
of psoriasis
d) Differential diagnoses include syphilis and
nutritional deficiency
10. Skin biopsies confirmed a diagnosis of
hypopigmented mycosis fungoides. Which
TWO statements are correct regarding
Joshua’s ongoing management?
a) Topical antifungal treatment is effective in
30% of cases
b) Ultraviolet therapy is effective in achieving
long-term remission
c) Follow-up is not necessary after resolution of
the hypopigmentation
d) Joshua may be reassured that his condition
will most likely be benign
CPD QUIZ UPDATE
The RACGP requires that a brief GP evaluation form be completed with every quiz to obtain category 2 CPD or PDP points for the 2014-16 triennium.
You can complete this online along with the quiz at www.australiandoctor.com.au. Because this is a requirement, we are no longer able to accept
the quiz by post or fax. However, we have included the quiz questions here for those who like to prepare the answers before completing the quiz online.
how to treat Editor: Dr Steve Liang
Email: [email protected]
Next week Zoonoses are infections or infectious agents transmitted from vertebrate animals to humans. The next How to Treat discusses the common zoonoses — Q fever, leptospirosis and
brucellosis – and several more uncommon conditions that should be considered in patients who present with unusual symptoms after having been in rural Australia and/or having had close contact
with farm animals. The author is Associate Professor Neil Parker, adjunct associate professor, school of public health, tropical medicine and rehabilitation sciences, James Cook University,
Townsville, Queensland.
30
| Australian Doctor | 18 April 2014
www.australiandoctor.com.au