When I was in medical school on my dermatology rotation, we joked that all skin treatments boil down to three decrees: If it’s wet, dry it. If it’s dry, wet it. And if in doubt, use steroids.
Some other time I’ll discuss the “drying” of skin, or the use of steroids (which are not, by the way, the kind of steroids taken illegally by athletes!) Today I’ll cover how to keep the skin “wet” – and some principles of moisturizing.
Skin is our first line of defense against disease. Bacteria, viruses, parasites – dangers lurk everywhere. But our epidermis (the outer layer of our skin) blocks them almost always. When people have inflamed skin, the epidermis becomes disrupted and infectious particles can enter their body.
The key to keeping the epidermis intact is keeping it moist. Now, I’m talking about moisture just below the surface of the skin (within the epidermis), so the outside surface doesn’t feel wet. There are molecules within the epidermis that hold onto water, and which draw water to the area – from both directions. That is, from deeper inside the body and from the outer surface of the skin.
Dry skin is itchy skin. There are skin diseases which lead to excessive water loss from the epidermis, the most common being eczema, or “atopic dermatitis”. Even those of us without eczema, however, can benefit by keeping our epidermis as moist as possible.
There are three basic types of moisturizers: lotions, creams, and ointments. A lotion is water based, which means that after you rub it in, the water in the lotion will evaporate. This makes lotions not the best option for dry skin, for you may end up having less moisture in the epidermis than you did before.
A cream has a small amount of water and more oils than a lotion, in addition to various chemicals which help to keep it from feeling greasy. An ointment has no water at all, which makes it a barrier keeping water from evaporating.
The most effective way to keep water in the epidermis is to apply either a cream or an ointment right after a bath or shower. During the shower, it’s best not to scrub the skin, but just gently wash with soap or another cleanser. Then, immediately after toweling off, apply a cream or ointment. The water from the shower is trapped on the skin, and is slowly absorbed into the epidermis.
Oily skin benefits from moisturizers, also, but it’s best to use one that doesn’t fill the pores, which might lead to an acne flare. Look for “non-comedogenic” on the label.
Three creams which many dermatologists recommend are Eucerin, Cetaphil and Nutraderm. For ointments, the cheapest way to go is plain old petroleum jelly (brand name Vaseline). Dermatologists also often recommend the ointment Aquaphor.
As people get older, their skin tends to be less oily because the glands that produce oil become less active. That means that more water evaporates from the surface of the skin, and less is trapped within the epidermis. So often older people find themselves needing a moisturizer, generally an ointment, for the first time.
*This blog post was originally published at Making Sense of Medicine*