Abstract
We report a nine-year-old girl who presented with a 3-month history of flat papules and erythemas on the inner side of the left lower limb. Physical examinations demonstrated flat papules, small erythemas, and irregularly shaped erythematous patches as a result of coalescence of the erythemas, forming a broad band along the Blaschko line. Histological examinations demonstrated moderate perivascular infiltration of lymphocytes and mild spongiosis and exocytosis in the epidermis. The lesions spontaneously healed one year after onset, leaving faint brown pigmentation. We diagnosed this patient as having pediatric onset blaschkitis. However, this disease entity has been controversial since its first report in 1990. The most serious problem is that blaschkitis cannot be distinguished from adult onset lichen striatus, a distinct subtype of classical lichen striatus. We consider that blaschkitis includes adult onset lichen striatus and would be differentiated from classic lichen striatus.
