[Lichen planus in children: role of the campaign for hepatitis B vaccination].

INTRODUCTION

Cutaneous lichen planus in children is a rare entity. To study its specific clinical and therapeutic features, we report on 8 cases seen in 5 years in a pediatric dermatology clinic. In parallel, this study addresses the role of HBV immunization campaigns in childhood lichen planus.

OBSERVATIONS

Six boys and two girls with a diffuse form of lichen planus were studied. The mean age was 11 years. Four children were of skin types V and VI. Lesions followed Blaschko's lines in two children. One case was associated with atopic dermatitis. In half the cases--the most recent--the eruption was noted after HBV immunization. Biopsy specimens from seven children were reviewed and confirmed the diagnostic of lichen planus. Oral retinoids or corticosteroids were used successfully in six cases.

DISCUSSION

Half of our cases confirmed the atypical features of lichen planus in childhood. This study confirms the predominance of lichen planus in children with pigmented skin suggesting a genetic predisposition. The eruption following Blaschko's lines suggests that a clonal keratinocytic population is the target of lichenoid inflammation. HBV immunization could be a stimulus triggering a cytotoxic lymphocyte-mediated reaction. The proportion of affected children was low in comparison with all children immunized. So lichen planus arises probably in predisposed children. This justifies surveillance in the pediatric and dermatologic medical communities.