Hyperpigmented patches on the back

A 56-year-old Asian-American man presented with an intensely pruritic rash on his back that had worsened over the past several months. Initially attributing the itch to dry skin, he began to use a daily moisturizer, but the itch did not improve. The man reported constant use of a back-scratcher. No associated fevers, myalgia, joint pains, paresthesias, or prior injuries to ...