New insights in segmental vitiligo: case report and review of theories.

Segmental vitiligo and generalized vitiligo are in general considered to be separate entities. The aetiopathogenesis of segmental vitiligo remains unclear, although several hypotheses have been put forward including mainly neuronal mechanisms. The typical association with other autoimmune diseases, as seen in generalized vitiligo, seems to be significantly less in segmental vitiligo, although recent insights point towards a possible immune-mediated overlap between the two subtypes. In this article, we describe a case with simultaneous presence of segmental vitiligo, alopecia areata, psoriasis and a halo naevus. To our knowledge, this is the first case with this exceptional combination. This concomitant presence could support the involvement of a shared autoimmune-mediated process, and may provide new insights into the pathogenesis of segmental vitiligo and direct future research. In the light of this remarkable case, different possible aetiopathogenetic mechanisms leading to the clinical presentation of segmental vitiligo are discussed and a new three-step theory is proposed.