LAUSR

DEAR EDITOR, A 9-year-old boy presented with a 3-day history of asymptomatic brown patches that appeared suddenly on his feet (a). Diagnosis was unclear until the boy’s father noticed the boy’s socks had a similarly patterned stain (b). Further inquiry revealed the boy had been playing in a yard covered with fallen black walnuts. Three weeks later, the hyperpigmentation had self-resolved. The black walnut tree (Juglans nigra) is native to eastern North America and is used for its dark-stained wood and edible nuts. While historically it has been used for hair dye, no formal reports of use as skin dye exist. Our case highlights this unexpected source of exogenous pigmentation.