Erythema dyschromicum perstans is a rare, chronic, pigmentary disorder with unknown etiology. It clinically presents with oval to round, gray, blue, or brown macules of various sizes. The etiology remains unknown; however, cobalt allergy, radio contrast media, intestinal parasites, human immunodeficiency virus, and hypothyroidism have been proposed as causative factors. In addition, vitiligo is characterized by depigmented macules and patches that are widely and symmetrically distributed. It

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... been suggested that autoimmune mechanisms play an important role in the etiopathogenesis of vitiligo. Physical and emotional stress can trigger vitiligo in genetically predisposed patients. However, coexistence of erythema dyschromicum perstans and vitiligo is extremely rare, and similar immune mechanisms have been implicated in the pathogenesis of these cutaneous pigmentary disorders.