Vitiligo: what are the causes of this disease?

Vitiligo is a skin condition characterized by the appearance of white patches on the skin.

Where do these white spots come from? What are the causes of this disease?

All the answers to your questions can be found in this sheet.

Vitiligo, what is it?

Vitiligo is a skin condition characterized by the appearance of white spots on the feet, hands, face, lips or any other part of the body. These spots are caused by « depigmentation », ie the disappearance of melanocytes, the cells responsible for the color of the skin (pigmentation).

The depigmentation can be more or less important, and the white spots, of variable sizes. In some cases, the hair or hair that grows inside the depigmented areas is also white. Vitiligo is neither contagious nor painful, but it can cause significant psychological distress.

Vitiligo is a disease whose symptoms are mainly aesthetically embarrassing, the spots not being painful or directly dangerous to health. Consequently, vitiligo is often « minimized » and is still insufficiently treated by doctors. However, it is a disease that has a very negative impact on the quality of life of those affected, as confirmed by a study . People with dark skin are particularly affected.

Types of vitiligo

There are several types of vitiligo :

Segmental vitiligo

Localized on only one side of the body, for example on part of the face, upper body, leg or arm. This form of vitiligo appears more often in children or adolescents. The depigmented area corresponds to a “territory of innervation”, that is to say an area of ​​the skin innervated by a particular nerve. This form appears rapidly over a few months, then usually ceases to evolve.

generalized vitiligo

It presents in the form of spots that are often more or less symmetrical, affecting both sides of the body, in particular areas of repeated friction or pressure. The term « widespread » does not necessarily mean that the spots are extensive. The evolution is unpredictable, the spots being able to remain small and localized or to spread quickly.

vitiligo universalis

Rarer, it spreads rapidly and can affect almost the entire body.

Vitiligo: who is affected?

Vitiligo affects approximately 1% to 2% of the population. It generally appears around the age of 10 to 30 (half of those affected are affected before the age of 20).

Vitiligo is therefore quite rare in children. It affects both men and women, and occurs all over the world, on all skin types.

The causes of vitiligo

The causes of vitiligo are not well known. However, we know that the appearance of white spots is due to the destruction of melanocytes, the skin cells that produce melanin.

Once the melanocytes are destroyed, the skin becomes completely white. Several hypotheses are now put forward to explain the destruction of melanocytes . Vitiligo is probably a disease that has both genetic, environmental and autoimmune origins.

Autoimmune hypothesis

Vitiligo is a disease with a strong autoimmune component. Indeed, people with vitiligo produce abnormal antibodies that directly attack melanocytes and help destroy them. Moreover, vitiligo is often associated with other autoimmune diseases, such as thyroid disorders, which suggests the existence of common mechanisms.

Genetic hypothesis

Vitiligo is also linked to genetic factors, not all of which have been clearly identified . It is common for several people to have vitiligo in the same family. At least 10 genes are involved, as shown in a study in 201024. These genes play a role in the immune response.

accumulation of free radicals

According to several studies , the melanocytes of people with vitiligo accumulate many free radicals, which are forms of waste produced naturally by the body. This abnormal accumulation would lead to a « self-destruction » of the melanocytes.

Nervous hypothesis

Segmental vitiligo results in depigmentation of a delimited area, corresponding to the area innervated by a given nerve. For this reason, researchers have thought that the depigmentation could be linked to the release of chemical compounds from the ends of the nerves, which would decrease the production of melanin.

Environmental factors

Although they are not the cause of vitiligo strictly speaking, several triggering factors can contribute to the appearance of spots (see risk factors).

Melanocytes and melanin

Melanin (from the Greek melanos = black) is a dark pigment (of the skin) produced by melanocytes; it is responsible for the color of the skin. It is mainly genetics (but also exposure to the sun) that dictates the amount of melanin contained in the skin. Albinism is also a pigmentation disorder. Unlike vitiligo, it is present from birth and results in a general lack of melanin in the skin, body hair, hair and eyes.

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Vitiligo: what evolution?

Most often, the disease progresses at an unpredictable rate and can stop or spread without knowing why. Vitiligo can evolve in phases, with aggravations sometimes occurring after a psychological or physical triggering event. In rare cases, the plaques go away on their own.

Apart from the aesthetic damage, vitiligo is not a serious disease. However, people with vitiligo have an increased risk of having skin cancer, because the depigmented areas no longer act as a barrier to the sun’s rays. These people are also more likely to suffer from other autoimmune diseases. However, this is not the case for people with segmental vitiligo.

Vitiligo: symptoms

Vitiligo is characterized by chalky-white patches that are well-defined by a band of darker skin. The first spots appear most often on the hands, arms, feet and face, but they can occur on any area of ​​the body, including the mucous membranes.

Their size can vary from a few millimeters to several centimeters. The spots are usually painless, but they may be itchy or burning when they appear.

Vitiligo: people at risk

People with another disease of autoimmune origin. Thus, many people with vitiligo have another concomitant autoimmune disease, such as alopecia areata, Addison’s disease, pernicious anemia, lupus or type 1 diabetes. In 30% of cases, vitiligo is associated with an autoimmune disorder of the thyroid gland, namely hypothyroidism or hyperthyroidism.

People who have a family history of vitiligo (seen in about 30% of cases).

Vitiligo: risk factors

In people at risk, certain factors can trigger vitiligo:

• a great emotional shock or intense stress would sometimes be involved ²² ;
• wounds, cuts, repeated friction, strong sunburn or contact with chemicals (phenols used in photography or in hair dyes) can cause vitiligo spots in the affected area.

Vitiligo: preventive measures

Currently, there is no way to prevent vitiligo, the causes of which are not known. However, it is important that sufferers protect themselves from the sun.

Preventing Skin Cancer The bleached skin of people with vitiligo has lost its protection from the sun, making it more prone to sunburn and, in the long run, skin cancer. In addition, it happens that burns enlarge the areas of depigmentation.

Therefore, it is essential for these people to protect themselves from the sun with a minimum SPF 30 sunscreen applied 30 minutes before exposure to the sun (check that the screen protects against UVA and UVB rays). It is important to stay in the shade from 12 p.m. to 4 p.m., the sun being at its zenith.

Vitiligo: treatments

There is no treatment that can cure vitiligo. However, current treatments make it possible to limit the size and number of depigmentation spots.

In children, doctors rarely resort to vigorous treatment and most often favor protection from the sun and camouflage with clothing.

Camouflage by cosmetics

Applying cosmetics to depigmented areas, such as specialized foundations (Dermacolor®, ColorTration®, Kamaflage® in Canada, Couvrance® Unifiance®, Covermark® in France) or self-tanning creams, helps to make the discoloration less apparent. of the skin, without however treating the disease.

Likewise, self-tanning creams can be helpful, as they work even in the absence of melanocytes. Cosmetics are especially helpful for people who have vitiligo patches around the eyes, where topical corticosteroids and UV light are contraindicated.

Repigmentation treatments

The objective of these treatments is to stimulate the multiplication of melanocytes still present in the skin. Dermatologists would be able to achieve repigmentation in several cases, especially if treated early. Repigmentation can be done by two processes: phototherapy or topical (local) treatments.

Topical treatments may be prescribed to repigment small spots of vitiligo. These creams reduce the activity of the immune system (including the autoimmune reaction), which has the effect of stopping the destruction of melanocytes. They must be applied once a day for several months. Unfortunately, they are not effective in all cases. Corticosteroid creams are often prescribed to be applied to recent spots.

Be careful not to exceed the number of prescribed applications, as this can lead to thinning (atrophy) of the skin. These creams are sometimes prescribed to children, with increased supervision. Topical immunomodulators, pimecrolimus (Elidel® in Canada) and tacrolimus (Prograf® in Canada, Protopic® in France) in cream, can also be applied to the spots. They only seem effective on localized spots on the neck and face .

Photochemotherapy by the method PUVA (combination of psoralen and UVA rays) consists in combining the exposure of the skin to UVA rays with the taking (orally, topically or in the form of a bath) of a substance called psoralen. Psoralen, ingested 2 to 3 hours before phototherapy, makes the skin more sensitive to ultraviolet rays. Oral psoralen is generally reserved for extensive forms of vitiligo (more than 20% of the body surface affected).

The treatment requires great diligence since it takes place in several sessions (from 100 to 300) at a rate of 1 to 3 times a week. You have to wait about 2 or 3 months (or 200 sessions) to obtain a visible effect. “PUVAtherapy” is quite effective, but total repigmentation is only obtained in 15% to 20% of people treated22. It can cause itching, pain, and a sunburn-like burn. In the long term, this treatment slightly increases the risk of skin cancer  .

Contraindication: photochemotherapy is contraindicated for children under 12 and pregnant or breastfeeding women.

Narrow-spectrum UVB phototherapy is a newer method of phototherapy that does not require taking or applying psoralen, and is therefore simpler than PUVA photochemotherapy. It is based on exposure to ultraviolet B radiation which stimulates the repigmentation of dark spots. It is mainly intended for cases of extensive vitiligo and is especially effective on facial lesions.

Up to 3 sessions can be administered per week and there are fewer immediate side effects than with the PUVA method (less burning or pain). Doctors still lack perspective to compare UVB phototherapy to PUVAtherapy, but the first clinical trials have been very encouraging . This technique can even be offered to some children with very troublesome forms of vitiligo.

The use of the laser (308 nm excimer type) seems promising3, but there are still few clinical trials.

Depigmentation treatments

The goal here is to permanently depigment the entire skin to achieve an even appearance. This therapeutic option is quite radical and is only considered when vitiligo covers most of the body (vitiligo universalis). “Whitening” chemical solutions (eg Benoquin®) are applied every day for more than a year.

However, half of the people treated would suffer from side effects (redness and dryness of the skin, burns, etc.), and once the treatment is finished, exposure to the sun should be avoided as much as possible since the skin becomes strong there. sensitive.

Surgical treatments

In some cases, especially when the body hair and the hair itself are depigmented, skin grafts can be offered. These grafts are especially suitable for people with segmental vitiligo, that is to say, affecting only one part of the body and no longer evolving. These are autologous transplants, that is to say that the grafts are taken from the patient himself, in areas of the body that are not affected by vitiligo.

This makes it possible to avoid transplant rejection and the taking of immunosuppressive drugs. A new technique, melanocyte transplantation (or “melanocyte transplant”) makes it possible to recover melanocytes from healthy areas of skin and inject them into depigmented spots. Still experimental, this treatment is however not available everywhere.

Support group

Because it changes the appearance and often affects visible areas of the body, such as the hands, face and arms, vitiligo can cause discomfort and some embarrassment in front of others. Aesthetic damage can sometimes be the cause of real psychological distress, which should not be minimized and which must absolutely be taken care of. For people who feel the need to talk about this, support groups can provide important emotional support. Psychotherapy can also bring relief to some patients.