Page 162 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-77 Integumentary System
VITILIGO
Vitiligo affecting
both skin and hair
Vitiligo is a common acquired skin disease with multi-
ple clinical variants. Vitiligo occurs because of loss of
function or complete loss of melanocytes within the
epidermis and follicular epithelium. There are many
theories as to its development, but it is believed to be
an autoimmune skin disease. Vitiligo may be seen in
association with other autoimmune conditions. Patients
afflicted with vitiligo can be psychologically affected by
the disease.
Clinical Findings: Approximately 1% of the popula-
tion is affected by vitiligo. It has been reported to occur
at any age, but it is most common in the teenage years
and the early twenties. There is no sex or racial predilec-
tion. A small percentage of cases are familial in nature.
The exact inheritance pattern and the reason for this
configuration are unknown. Many clinical variants of
vitiligo exist. All forms have varying degrees of involve-
ment of the skin. When melanin is no longer produced,
patients are left with depigmented macules. These
macules appear as stark white areas of skin, which can Localized burning within the areas
be a few millimeters to many centimeters in diameter. of vitiligo secondary to phototherapy
The areas of involvement have a well-defined border is a potential side effect
region. Hair within the areas of depigmented skin may
also be depigmented. With time, the loss of pigment in
the hair becomes more prominent. Hair depigmenta-
tion within the regions of vitiligo is not universal, and
normal-appearing pigmented hair may grow within
such an area. Most commonly, no inflammation is seen,
and the areas are completely asymptomatic in nature. Symmetric
Patients with Fitzpatrick type I skin are less obviously vitiligo
affected than those with Fitzpatrick type VI skin. The
areas of vitiligo will not tan after sun exposure. Sun
exposure typically makes the difference between
affected and nonaffected skin more noticeable, because
it increases melanin production in the unaffected skin,
resulting in a darkening or tanning of the skin around
the vitiliginous region. The areas of vitiligo are prone
to easy burning and must be protected.
Various clinical variants or classifications of vitiligo
exist, including localized, generalized, linear, trichrome,
and blaschkoid variants. The generalized form can
cause near-universal involvement of the skin, with a
only few tiny islands of normal-appearing skin remain- Various clinical presentations of vitiligo
ing within the areas of vitiliginous skin. Linear areas of
involvement are rare and typically affect a limb. Blasch-
koid vitiligo follows the embryological Blaschko lines.
Histology: There is no inflammation, and hematoxy-
lin and eosin staining of the biopsy specimen may
appear normal unless compared with a biopsy specimen
from unaffected skin. When this is done, the lack of
melanin production and melanocytes is appreciated.
Special staining to accentuate melanocytes can make
them much more visible.
Pathogenesis: The exact cause of vitiligo has yet to
be determined. The leading theory on its development
is the autoimmune theory. An unknown trigger causes
the immune system to begin destroying melanocytes.
The immune system recognizes melanocytes as
somehow abnormal and causes their destruction. The
autoimmune theory also may explain why vitiligo is immunomodulators such as tacrolimus and pimecroli- centered on the hair follicles. The hair follicle is
seen clustered with diabetes, thyroid disease, and other mus have been used. Phototherapy with narrow- believed to be a reservoir of melanocytes for repopula-
autoimmune conditions. band ultraviolet B light (UVB) and with psoralen + tion of areas that are devoid of their normal comple-
Treatment: Patients with vitiligo should be screened ultraviolet A light (PUVA) has been used successfully. ment of melanocytes.
for underlying autoimmune conditions such as diabe- The risk of burning is very high in the affected regions, Rarely, complete depigmentation is undertaken, for
tes and thyroid disease. The treatment of these con- and care should be used when starting this treatment. those who are so severely affected that only a few islands
ditions has not been shown to help the vitiligo. No Small areas have been treated successfully with surgical of normal-appearing skin remain, to allow for a uniform
therapy is needed. For those patients who seek treat- techniques involving autotransplantation of skin from skin tone. Monobenzylether of hydroquinone is used to
ment, many therapies are available, mostly on an anec- unaffected regions. If the therapy works, melanocyte eliminate any remaining melanocytes and depigment
dotal basis. Potent topical corticosteroids and topical rejuvenation typically occurs in a speckled pattern the skin.

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