Prurigo pigmentosa is a rare inflammatory cutaneous disorder associated with ketosis that resolves with reticulate hyperpigmentation. A 19-year-old man was admitted to the hospital with diabetic ketoacidosis. He also had developed reticulate papules coalescing into plaques over the posterior neck, back, and abdomen. Histopathological findings consistent with the clinical findings suggested the diagnosis of prurigo pigmentosa. After treatment with topical triamcinolone and oral doxycycline along with resolution of his ketosis after insulin administration, the patient's rash healed with reticulate hyperpigmentation.