Because irritation is a problem for skin, anything that irritates the skin should be avoided as much as possible. Heat is one of those things that should be avoided. As good as hot water, direct steam, or dry saunas feel on the skin, they end up causing more problems for the health of the skin. For years, I have recommended washing the face with tepid water. This is because hot water burns the skin and cold water shocks it, and both leave it irritated and dry. These two temperature extremes can also injure skin cells, dehydrate the skin, and cause capillaries to surface. Extreme temperatures in any form cause problems for the skin, but heat is the more attractive alternative (most people avoid a cold shower or bath).
Dry heat is clearly dehydrating. Whether the dry heat comes from a dry sauna or an arid desert climate, it pulls water right out of the skin cell. That’s bad for any skin type, but especially for someone with dry skin.
Wet heat is a bit more deceptive. We all know how great the skin feels initially when we exit a hot shower, Jacuzzi, or sauna. It feels plump and saturated with water because the skin absolutely loves drinking up all the water it can. After even a short soak in a tub, your skin can swell and become engorged with water. When you leave a bathtub and your fingers are all thick and wrinkly, it isn’t because they are dry, but because they are distorted and swollen with water-saturated skin cells. Because the surface layer of skin likes water so much, hot water can enter the skin, stay there, and cause a burn-like reaction. As a general rule, if water feels hot to the touch, it’s too hot for the skin, especially the face. Be very skeptical about facial treatments that involve the use of heat or washing your face with hot (or cold) water; down the line, they could cause more trouble for your skin than you want.