History of urea as a dermatological agent in clinical practice.

Urea, also known as carbamide, is a polar, hygroscopic molecule produced by the human body that was first discovered in urine in 1773 by the French chemist Hilaire Rouelle and was artificially synthesised from inorganic precursors in 1828 by the German chemist Friedrich Wohler. The importance of urea in dermatology is twofold: it primarily has a physiological key role for the maintenance of skin hydration, and it secondarily has been used for more than a century in different topical preparation and concentration in various skin conditions. One of the first uses of urea was the topical treatment of wounds because of its antibacterial and proteolytic properties. Since the second part of the 20th century, urea became one of the most common moisturisers and keratolytic agents, useful for the treatment of xerosis, atopic dermatitis, ichthyosis and psoriasis.