What causes vitiligo?
There are many theories about what causes vitiligo, and no one is positively
certain. However, many doctors and researchers believe that a genetic predisposition or
susceptibility to vitiligo exists in most people who develop vitiligo.
Vitiligo may result from a number of factors -- autoimmune, oxidative stress (excess of
hydrogen peroxide), neurotrophic (interaction of melanocytes and the nervous system), and toxic
(substances formed as a part of normal melanin production actually being toxic
to melanocytes) hypotheses have been advanced. The mechanism involves progressive
destruction of selected melanocytes, probably by cytotoxic T-cell lymphocytes.
Many believe that vitiligo is a type of autoimmune disorder,
in which the body's immune system sees the pigment cells in the skin as foreign
bodies, and attacks them. The basis for this autoimmune disorder is believed
by many to be genetic. Stress, traumatic events,
injury, or severe sunburns, may trigger or exacerbate vitiligo in those who
are susceptible, though this has not been substantiated.
Other theories include the possibility that an abnormally functioning nervous
system may produce a substance that injures melanocytes. Some believe that melanocytes
in vitiligo patients may self-destruct, releasing toxic byproducts that then
destroy other pigment cells. Another theory suggests that vitiligo is entirely
genetic, and that there is a defect in the melanocytes that makes them more
susceptible to injury.
We know that some cases of vitiligo arise from exposure to certain chemicals,
for example, phenols used in photography. Surgery wounds or injuries to the
skin have also been known to result in vitiligo, which can spread. The question
is, are those people susceptible to vitiligo to begin with. Many experts say
yes.
Finally, there are alternative theories about vitiligo that suggest diet, nutrition,
and digestive disorders may play a role in the destruction of melanocytes. Some
believe that internal pathogens within the digestive tract, such as yeast proliferation,
might relate to vitiligo.
What is oxidative stress?
This is one theory about what may cause or contribute to the onset or exacerbation of vitiligo. Oxidative stress is an over-accumulation of hydrogen peroxide in the skin. Every person
develops hydrogen peroxide in the skin, as a result of natural biological processes.
An enzyme called "catalase" normally breaks down the hydrogen peroxide
in the skin into water and oxygen. However, some people with vitiligo may have a
problem manufacturing, using or delivering catalase to the skin.
Is it true that genetics may play a part in vitiligo?
Most experts believe that there is a genetic base to vitiligo which leads to
susceptibility. In about 12% of families where a person has vitiligo, the condition is seen in another family member. Though
no one else in your family may show signs of vitiligo, it is still possible
that it is passed on genetically. The most likely reason for this is that more
than one gene is responsible for the development of vitiligo. In fact, a combination
of genes that may prove to be involved. In some cases, an independent stimulus may cause the condition to onset.
Genes are inherited in a random fashion from both parents, so only sometimes
will the genes which make a person susceptible to vitiligo come together in the same person.
Those who do not inherit a complete set of the abnormal genes are unlikely to develop the disorder. Those
people who do inherit a complete set may also need some other factor to trigger
the vitiligo patches to appear. In this way vitiligo genes can pass through
several generations of a family without anyone actually developing vitiligo.
Currently, researchers are studying the genetic aspects of vitiligo, using gene-sequencing
computers and the mapping of the human genome to determine how genetic therapy
and technology might help treat or arrest vitiligo.
What is genetic susceptibility?
This is the theory that the susceptibility or predisposition to vitiligo is
genetic, and that some defect in the genetic structure, makes people more susceptible
to vitiligo. While we do see vitiligo in more than one family member about 20%
of the time, about 80% of patients report no other family members with vitiligo.
Many experts agree that not everyone who is susceptible to vitiligo will necessarily
develop it. Recent genetic studies, which ran the DNA of hundreds of people with
vitiligo through gene sequencing computers, have produced important information about
the enzyme operations in the bodies of those with vitiligo, which may help researchers
better understand how to treat the underlying cause of vitiligo.
As with all genes, people may carry the defect that causes vitiligo,
and even pass it on to their children, without ever developing vitiligo themselves.
Thus other factors, including environmental and personality factors, may play
a role in the onset (beginning) of vitiligo.
Is it true that exposure to certain chemicals can cause vitiligo?
Some chemicals, particularly photography chemicals such
as Phenols, can trigger vitiligo in those who are susceptible. Phenols can also be found in many types of
hair colorings, household stains, and similar products. There are other
industrial chemicals and substances which may also trigger the onset of vitiligo.
Are there things that a person with vitiligo should avoid?
In addition to the phenol type chemicals listed in the previous paragraph, there are other things and activities which people
with vitiligo should avoid. Unfortunately, the list of activities, products and chemicals to avoid varies, depending
on who you talk to. Our Main Message Board has numerous topics about this subject, however, we will be updating this section shortly, with a list of some of the things many people agree may make vitiligo worse.
Are there any other symptoms? Will Vitiligo lead to other conditions or diseases?
Other than the white patches of skin, there are no other physical symptoms of
vitiligo. As a secondary effect, vitiligo patches will tend to sunburn more
easily, and sunscreen is often recommended. Though some websites suggest eye
color and vision may be affected by vitiligo, experts indicate that any
effect on eye color or the retinal pigment is extremely rare, and any impairment
of vision, even rarer.
Are there other conditions related to vitiligo?
Vitiligo in of itself does not appear to "lead" to other conditions. However,
there are other autoimmune-related conditions, which may arise in vitiligo patients,
and that may even arise from the same genetic disorder that results in vitiligo.
Thyroid disorders (especially hypothyroidism) are quite common in those with
vitiligo, and many doctors feel treating thyroid disorders is important in treating
vitiligo. Other related autoimmune conditions are much rarer, but include alopecia
areata, pernicious anemia, lupus, and occasionally diabetes. To worry that these
other conditions will arise is unwarranted, as they are not very common. But
understanding these other conditions, and knowing about their symptoms, may
be wise.
Nevertheless, most people with vitiligo have no other autoimmune disorders.
How is thyroid function related to vitiligo?
Thyroid disorders are extremely common in every ethnic and racial group on the
planet.
The thyroid is a small, butterfly-shaped gland just below the Adam's apple.
This gland plays an important role in controlling the body's metabolism,
that is, how the body functions. It does this by producing thyroid hormones
(T4 and T3), chemicals that travel through the blood to every part of the body.
Thyroid hormones tell the body how fast to work and use energy.
Because vitiligo may well be related to numerous functions within the body,
a properly functioning thyroid (or sufficient supplemental hormone) could be
important in treating vitiligo.
which teaches children that there are many different people in the world,
and that they really are very much alike, despite their obvious differences.
