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What is Vitiligo?
Vitiligo is a disorder in which patches of white skin appear
on various parts of the body. The skin is white because the cells
responsible for producing brown pigment have disappeared from the
affected areas. Vitiligo is a common condition afflicting 3-5% of
the population and although it may appear at any age, it most commonly
commences in childhood or early adult-life.
Vitiligo is an inherited condition but it frequently skips generations
so that only 60-80% of patients know of a family member with the condition.
How a genetic defect leads to loss of pigment cells in the skin is
only poorly understood. It appears that the immune defense system
of the body recognizes the cells as "foreign" and not self
and proceeds to kill them. The fact that only some pigment cells are
killed and not all of them suggests the defect lies in the cells themselves.
Diagnosis of Vitiligo
Vitiligo can usually be readily diagnosed without resort to any special
investigation. Most patients are otherwise healthy and the disorder
is limited to the skin. However, about one in five patients have had,
or will have, increased or decreased function of the thyroid gland.
If any symptoms suggest a thyroid disturbance this can easily be investigated
by appropriate blood tests.
The Course of Vitiligo
Once vitiligo has appeared its course is erratic and unpredictable.
The only statement which can be made with certainly is that it is
very unlikely that vitiligo will go away. Some patients remain stable
without any progression for many years, while at the other extreme
some patients show rapid progression over only a few months.
Several studies, involving years of observations of large number of
patients, have attempted to identify markers to allow prediction of
the probable course in the individual patient. The only marker identified
in this way is that if the vitiligo appears at the sites of trauma
to the skin, such as an abrasion or scratch mark, then fairly rapid
progression is more likely.
Approaches to Treatment of Vitiligo
Vitiligo is often brushed aside as being "just a cosmetic defect"
with the inference that it does not require any treatment. This is
incorrect because every patient requires some treatment. The treatment
should be tailored individually to the needs of the patients, the
extent and location of the vitiligo, and the likely response to the
given treatment. The possible approaches are:
Sunscreen and Avoidance of the Sun
This is the minimum treatment that must be used by any patient with
vitiligo on exposed areas of the body.
The reason is simple: the skin in a patch of vitiligo has lost most
of its protection against the damaging effects of ultraviolet light
in sunlight. If left unprotected, premature aging of the skin and
ultimately skin cancer are inevitable consequences. A patient with
vitiligo should avoid exposing the white areas to sunlight. If exposure
is inevitable, as for example with vitiligo on the face and hands,
daily application of a sun- screen SPF 15 or higher is essential from
March to November.
Masking
Masking Dyes are available which can be applied to the
skin every few days to camouflage areas of vitiligo. However, the
usefulness of these preparations varies between individuals and in
general it is most successful in olive-skinned people. In fair-skinned
and black people, it tends to have a greenish hue. It is most important
to remember dyes do not provide any protection against sunlight.
Cosmetics are available to mask small areas of vitiligo on the face
and these can be matched to the normal skin color.
Repigmentation
Treatment with ultraviolet light therapy is the main means of restoring
pigment to the white areas of vitiligo. Two types of light therapy
are effective in vitiligo. PUVA therapy and narrow-band UVB (311)
phototherapy. PUVA therapy consists of taking a medication called
psoralens and then being exposed to ultraviolet A light. Psoralens
are distributed to the skin and there interact with the UVA light
to stimulate formation of new pigment cells in the skin. Narrow-band
phototherapy does not involve taking a medication and has a similar
but probably less powerful effect on pigment cells.
PUVA therapy has been used in India and the Middle-east for several
thousand years for treatment of vitiligo and it has been used in America
since 1952. Sunlight was used as the source of UVA light, but recently,
more effective indoor sources of light have been developed. These
improvements to the treatment have resulted in much better response
rates and also have allowed definition of what the likely response
will be in an individual patient. Narrow-band phototherapy was introduced
about 10 years ago.
Light therapy produces some repigmentation in almost all patients
but the extent of repigmentation does vary. The chief determinant
of the response is the location of the vitiligo. Vitiligo on the face
almost always responds completely, the trunk has a less favorable
response and so on down to the tips of the fingers and toes, which
almost never respond. The duration and extent of vitiligo do not influence
the response.
Treatment has to be given two or three times each week. A trial of
thirty treatments gives a fairly accurate indication of whether or
not treatment will be worthwhile. If there is no response by treatment
number thirty, it is pointless to continue. Treatment number fifty
is the next milestone: if the response is not sustained it is unlikely
that further repigmentation will occur.
Light therapy does not stop new areas of vitiligo appearing and repigmented
areas can lose pigment again. However, it is very unusual for a patient
to continue to show progression of vitiligo after 20-30 treatments.
Furthermore, if a given patch of vitiligo is completely repigmented
and filled in, it is very unusual to again lose the pigment; partial
repigmentation of a patch is frequently lost.
The most recent light treatment for vitiligo involves use of an excimer
laser. This is only practical for small areas of vitiligo and it is
regarded as experimental by most insurance carriers. *Note that other
sources of ultraviolet light such as sunlight and tanning parlors
rarely produce pigmentation in vitiligo.
Skin Grafting
This is a technique used to supplement the effect of PUVA therapy
in returning pigment to the skin. The cells that make brown pigment
are in the most superficial, outer layer of the skin and this layer
can be painlessly and easily raised by a suction machine that forms
a blister. The superficial grafts are taken from the buttocks and
transferred to white areas of vitiligo. Two or three weeks after grafting,
PUVA therapy is resumed and the grafts expand to help fill in the
white areas.
Depigmentation
A few patients have such extensive vitiligo that consideration can
be given to attempting removal of the remaining pigment so the skin
is all one color. Usually this is not worth considering unless the
vitiligo covers at least 90% of the body. The agent used to remove
pigment is applied as a cream and since it is slow acting, treatment
is necessary daily for 6-12 months. The main problem with this treatment
is that it can trigger an allergic reaction in the form of eczema
and this usually means the treatment has to be suspended.
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