More than just dermatitis: The multifaceted nature of chronic itch through the historical perspective of Napoleon Bonaparte.

Derived from the survival advantage needed to eradicate harmful irritants from the skin's surface, itch, also known as pruritus, is an intriguing phenomenon and a key feature of many dermatologic diseases. The pathologic form, chronic itch, is a condition that precedes itself by its complex pathophysiology, numerous etiologies, and interplay of mechanisms that often make it difficult to diagnose and treat. One particular sufferer of this condition, the 18th-century French emperor Napoleon Bonaparte, makes for a compelling case study of the complexity of chronic itch. We delve into the many etiologies and mechanisms of chronic itch, using Napoleon's lifelong struggle with this condition as our model, identifying potential environmental, neurologic, psychiatric, and immunologic origins of his condition.