What Is Vitiligo?
Vitiligo (vit-ill-EYE-go) is a
pigmentation disorder in which melanocytes (the cells
that make pigment) in the skin are destroyed. As a
result, white patches appear on the skin in different
parts of the body. Similar patches also appear on both
the mucous membranes (tissues that line the inside of
the mouth and nose), and the retina (inner layer of the
eyeball). The hair that grows on areas affected by
vitiligo sometimes turns white.
The cause of vitiligo is not known, but
doctors and researchers have several different theories.
There is strong evidence that people with vitiligo
inherit a group of three genes that make them
susceptible to depigmentation. The most widely accepted
view is that the depigmentation occurs because vitiligo
is an autoimmune disease—a disease in which a person’s
immune system reacts against the body’s own organs or
tissues. As such, people’s bodies produce proteins
called cytokines that alter their pigment-producing
cells and cause these cells to die. Another theory is
that melanocytes destroy themselves. Finally, some
people have reported that a single event such as sunburn
or emotional distress triggered vitiligo; however, these
events have not been scientifically proven as causes of
vitiligo.
Who Is Affected by Vitiligo?
About 0.5 to 1 percent of the world’s
population, or as many as 65 million people, have
vitiligo. In the United States, 1 to 2 million people
have the disorder. Half the people who have vitiligo
develop it before age 20; most develop it before their
40th birthday. The disorder affects both sexes and all
races equally; however, it is more noticeable in people
with dark skin.
Vitiligo seems to be somewhat more
common in people with certain autoimmune diseases. These
autoimmune diseases include hyperthyroidism (an
overactive thyroid gland), adrenocortical insufficiency
(the adrenal gland does not produce enough of the
hormone called corticosteroid), alopecia areata (patches
of baldness), and pernicious anemia (a low level of red
blood cells caused by the failure of the body to absorb
vitamin B12 ). Scientists do not know the
reason for the association between vitiligo and these
autoimmune diseases. However, most people with vitiligo
have no other autoimmune disease.
Vitiligo may also be hereditary; that
is, it can run in families. Children whose parents have
the disorder are more likely to develop vitiligo. In
fact, 30 percent of people with vitiligo have a family
member with the disease. However, only 5 to 7 percent of
children will get vitiligo even if a parent has it, and
most people with vitiligo do not have a family history
of the disorder.
What Are the Symptoms of Vitiligo?
People who develop vitiligo usually
first notice white patches (depigmentation) on their
skin. These patches are more commonly found on
sun-exposed areas of the body, including the hands,
feet, arms, face, and lips. Other common areas for white
patches to appear are the armpits and groin, and around
the mouth, eyes, nostrils, navel, genitals, and rectal
areas.
Vitiligo generally appears in one of
three patterns:
- focal pattern—the depigmentation is limited to
one or only a few areas
- segmental pattern—depigmented patches develop on
only one side of the body
- generalized pattern—the most common pattern.
Depigmentation occurs symmetrically on both sides of
the body.
In addition to white patches on the
skin, people with vitiligo may have premature graying of
the scalp hair, eyelashes, eyebrows, and beard. People
with dark skin may notice a loss of color inside their
mouths.
Will the Depigmented Patches
Spread?
Focal pattern vitiligo and segmental
vitiligo remain localized to one part of the body and do
not spread. There is no way to predict if generalized
vitiligo will spread. For some people, the depigmented
patches do not spread. The disorder is usually
progressive, however, and over time the white patches
will spread to other areas of the body. For some people,
vitiligo spreads slowly, over many years. For other
people, spreading occurs rapidly. Some people have
reported additional depigmentation following periods of
physical or emotional stress.
How Is Vitiligo Diagnosed?
The diagnosis of vitiligo is made based
on a physical examination, medical history, and
laboratory tests.
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