Prurigo pigmentosa.

A 22-year-old Chinese woman presented with a 5-year history of an intensely pruritic eruption on her posterior neck, mid back and sacrum leaving reticulate pigmentation. The diagnosis of prurigo pigmentosa was made on the basis of the clinico-histological features and a response to minocycline. Although prurigo pigmentosa is uncommon, it has characteristic clinical and histological features. Early diagnosis and appropriate treatment result in a rapid response and prevents a progression of pigmentation.