Dehydrated skin is often confused with dry skin - however, dry and dehydrated skin are two different phenomena. Dehydrated skin lacks water - dry skin lacks natural oils or sebum. Therefore, dry skin is a skin type, while dehydration is considered a condition. DEHYDRATED SKIN Dehydration happens when you use or lose more fluid than you ingest, and your body doesn't have enough water or liquids to carry out expected functions. If you don't replace lost fluids, you will get deh