Urea in the treatment of dry skin.

Urea is a unique physiological substance. It has frequently been used in dermatological therapy for more than 20 years. The relevant properties of urea with regard to its use in dermatological preparations are discussed in this brief review. Urea's natural presence in the horny layer, its water solubility, dipolar character and relation to concentrated solutions of electrolytes, are highlighted. The clinical use of urea creams is discussed with respect to indications, side-effects and combinations with other substances.