Prurigo pigmentosa (PP) is a rare skin disorder presenting as erythematous urticarial papules on the chest and leaving reticulated pigmentation. Although the etiology of PP is unknown, conditions associated with ketosis such as diabetes mellitus, ketogenic diet (KD), and anorexia nervosa are implicated. Herein, we report a 21-year-old woman who developed PP after adhering to a KD and responded to resuming a regular diet.