[Association of lupus erythematosus and vitiligo (author's transl)].

The authors report two cases with both true vitiligo and cutaneous lupus erythematosus (LE). The latter was found only on the vitiliginous areas on both exposed and non-exposed skin. A study of the literature shows that this association is very rare and, like the association between vitiligo and antinuclear antibodies, not statistically significant. It is therefore not possible to explain the pathogenesis of this association by a common autoimmune theory, although vitiligo is well known to coexist with other autoimmune disorders and although antimelanocyte antibodies are exceptionally found in certain cases of vitiligo. The coexistence of lupus erythematosus and vitiligo must be clearly distinguished from post lupus depigmentation which is much more common. In the latter there is clinically an irregular hypomelanosis and an atrophic epidermis and, histologically, there is a pigmentary incontinence with an increased number of melanocytes. Even if it is fortuitous, the appearance of LE lesions on light exposed vitiliginous areas may be explained by the common photosensitivity of these two disorders. However, this superimposition does not explain the common points between these two diseases nor the localization on non-light exposed skin. The localizing role of vitiligo in these exceptional cases could represent a more complex disorder of the dermo-epidermal junction. This disorder could affect more than the melanocytic system and subsequently favour the occurrence of the LE. Nevertheless, the mechanism of this coexistence still remains unknown.