Association rare: lichen scléroatrophique extragénital et vitiligo inflammatoire chez un enfant

Scleroatrophic lichen (SL) and vitiligo are two depigmenting disorders which may occur separately or, rarely, in combination. Their association may seem logical because both these disorders are characterized by the suspicion of an autoimmune pathogenesis. We here report the case of a 8-year old girl, with no notable medical history, presenting with achromic macules and papular nonpruritic lesions evolving over 6 months. Clinical examination showed two types of lesions (A): ovalaire achromic macules measuring 1-3 cm along their longer axis, located at the level of the front, of the neck, of the shoulders, as well as of the peri-mamelonar and of the genital region. These lesions exhibited slightly raised peripheral inflammatory border as well as a poliosis. The patient also had pearly white atrophic papular plaques at the level of the interscapular and abdominal regions as well as of the anterior face of the knees. Two biopsies were performed. Histological examination of an achromic macula showed vitiligo with inflammatory reaction while histological examination of an infiltrated lesion allowed the diagnosis of scleroatrophic lichen. Significant clinical improvement was obtained by local treatment with dermocorticoids. Therefore, this pathological association between scleroatrophic lichen and vitiligo in our patient, highlights the key role of epidermal lichenoid inflammatory process in the disappearance of melanocytes and, possibly, in the induction of a auto-immune process.