Chapter 054. Skin Manifestations
of Internal Disease
(Part 9)

a
Absence of melanocytes.
b
Normal number of melanocytes.
c
Platelet storage defect and restrictive lung disease secondary to deposits of
ceroid-like material; one form due to mutations in β subunit of adaptor protein.
d
Giant lysosomal granules and recurrent infections.
The differential diagnosis of localized hypomelanosis includes the
following primary cutaneous disorders: idiopathic guttate hypomelanosis,
postinflammatory hypopigmentation, tinea (pityriasis) versicolor, vitiligo,
chemical leukoderma, nevus depigmentosus (see below), and piebaldism (Table
54-9). In this group of diseases, the areas of involvement are macules or patches
with a decrease or absence of pigmentation. Patients with vitiligo also have an
increased incidence of several autoimmune disorders, including hypothyroidism,
Graves' disease, pernicious anemia, Addison's disease, uveitis, alopecia areata,
chronic mucocutaneous candidiasis, and the polyglandular autoimmune syndromes
(types I and II). Diseases of the thyroid gland are the most frequently associated
disorders, occurring in up to 30% of patients with vitiligo. Circulating
autoantibodies are often found, and the most common ones are antithyroglobulin,
antimicrosomal, and antithyroid-stimulating hormone receptor antibodies.
There are four systemic diseases that should be considered in a patient with
skin findings suggestive of vitiligo—Vogt-Koyanagi-Harada syndrome,
scleroderma, onchocerciasis, and melanoma-associated leukoderma. A history of
aseptic meningitis, nontraumatic uveitis, tinnitus, hearing loss, and/or dysacusis
points to the diagnosis of the Vogt-Koyanagi-Harada syndrome. In these patients,

al
Characterist
ics
Woo
d's Lamp
Examinatio
n (UV-
A;
Peak = 365
nm)
Skin
Biopsy
Specimen
Patho
genesis
Tre
atment
Idiopath
ic guttate
hypomelanosis

Com
mon;
acquired; 1–
4 mm in
diameter
Shins
and extensor
forearms
Less

Type
of
inflammatory
infiltrate
Block
in transfer of
melanin
from
Trea
t
underlying
inflammato
subacute
lupus, or
after the
lesion fades,
as in
dermatitis
Usual
ly less
enhancemen
t than in
vitiligo
depends on
specific
disease
melanocytes
to
keratinocyte
s could be

on of
stratum
corneum by
the yeast
Sele
nium
sulfide
2.5%;
topical
neck
Shawl
-like
distribution
Youn
g adults
Macul
es have fine
white scale
when
scratched
corneum
Malassezia

Yeast
is lipophilic
and
produces C
9

and C

Possi
ble
autoimmune
phenomenon
that results
in
destruction
of
Topi
cal
glucocortic
oids;
topical
calcineurin
inhibitors;
UV-B;
Perior
ificial—
around
mouth, nose,
eyes, nipples,
umbilicus,
anus
Other
areas—
flexor
wrists,
extensor
distal
extremities

widespread

Chemica
l leukoderma
Simila
r appearance
to vitiligo
Often
begins on
hands
Satelli
te lesions in
areas not
exposed to
chemicals
More
apparent
Chalk
-white
Decrea
sed number
or absence of
melanocytes
Expos
ure to
chemicals
that
selectively
destroy
melanocytes,

White
forelock
Areas
of
hypomelanos
is contain
normally
pigmented
and
hyperpigmen
ted macules
of various
Enha
ncement of
leukoderma
and
hyperpigme
nted
macules
Hypo
melanotic
areas—
few to
no
melanocytes
Defec
t in
migration of
melanoblasts
from neural

upper and
lower
extremities
the tyrosine
kinase
receptor for
stem cell
growth
factor
Note: PUVA, psoralens +ultraviolet A irradiation; UV-B, ultraviolet B.