Segmental vs Non-segmental Vitiligo: What are the differences?

Vitiligo is an autoimmune disease affecting skin pigmentation that does not always present in the same way. Two main forms can be distinguished: segmental vitiligo and non-segmental vitiligo, which differ in their distribution, progression, and underlying biological mechanisms.

• An asymmetric vs symmetric distribution.

  The first distinction between segmental and non-segmental vitiligo lies in the distribution of lesions. Indeed, segmental vitiligo only affects one part of the body, of varying size. It is often a dermatome, an area of skin innervated by a single nerve root. This type is also distinguished by its unilateral distribution on the body. In contrast, non-segmental vitiligo manifests as bilateral and often symmetrical hypochromic macules, which appear simultaneously or progressively on both sides of the body, on the face for example, but also the hands or feet.

  The differences in distribution between segmental and non-segmental forms of vitiligo could be explained by variations in their pathogenesis. In the case of segmental vitiligo, some scientists hypothesise that the localised damage is due to overactivity in a dermatome, releasing pro-inflammatory neuropeptides and free radicals, causing targeted destruction of melanocytes in the area. Conversely, the bilateral distribution of non-segmental vitiligo is thought to be linked to its systemic nature, where the immune system attacks melanocytes in a more widespread manner throughout the body.

• A stable evolution vs unpredictable.

  The vitiligo segmental is known for its rapid progression followed by stabilisation. Indeed, after the appearance of lesions in a specific area, they generally progress for a few months before stabilising. This differs from non-segmental vitiligo, which spreads unpredictably, sometimes over several years, with a alternation of progression and regression phases. Certain triggering factors, such as stress, skin trauma or exposure to mites, can be implicated. The instability of vitiligo non-segmental makes its management more complex.

• Different ages of onset.

  We also observe a certain disparity in the age of onset between segmental and non-segmental vitiligo. Indeed, segmental vitiligo typically manifests quite early in life. It is estimated that about 40% of cases begin before the age of ten. This is different for non-segmental vitiligo. Although it can occur at any age, it tends to develop during adolescence. It should be noted that the majority of cases of vitiligo non-segmental are diagnosed before the age of 30.

• Different approaches to care.

  Finally, it is interesting to note that treatment modalities vary slightly depending on whether it is a case of segmental vitiligo or non-segmental. Indeed, the management of active non-segmental vitiligo is generally done by combining a short course of cortisone treatment and UVB phototherapy. In over 90% of cases, this treatment allows to halt the progression. If this is not sufficient, creams based on immunosuppressants, such as tacrolimus or pimecrolimus, can be prescribed in addition to UVB phototherapy.

  However, these treatments are generally ineffective on segmental vitiligo. Most often, it is necessary for patients to resort to a autologous melanocyte graft, that is, the grafting of melanocytes directly from their own skin. After this procedure, repigmentation gradually takes place, usually reaching its maximum between three and six months.

  Note : An autologous melanocyte transplant can also be considered for patients with non-segmental vitiligo who have not responded to traditional treatments.