Volume 18, No. 1, Winter 2010
By Paul M. Marz, M.D.
The weather outside is Frightful! Cold and low humidity and wind all take a toll on any and all exposed skin! Everyone takes skin for granted until there is some change in it. We even irradiate it with the sun for a “healthy” tan, even if that is actually harmful and dangerous. But so what? It’s just skin.
Skin is the largest, heaviest, most visible organ of the body, but what does it actually do?
To start, your skin keeps the outside out and the inside in.
Next, it is a natural thermometer/thermostat, turning pink when too warm and pale when too cold. On hot days, perspiration serves as a coolant. On cold days, to save on heating costs and prevent the body from getting too cold, it gets little to no blood at all. This keeps all that warmth deep inside.
Finally, there is a defensive mission. Bug bites or scratches inspire a brisk response by the skin, as with hives.
So, let’s talk about eczema or dry skin: This is a problem of keeping the inside in. Skin also serves as a moisture barrier that protects the body (97 percent water) from drying out. As a barrier, skin is really quite effective. It’s flexible, self-repairing, sensing, regenerating and never sleeps.
Anatomically, the top-most layer is called the epidermis. This layer is dead, so it can take quite a bit of abuse with few complaints. This top layer is the problem in eczema. It’s where that waterproofing material is located.
Examine any blister. The roof is good old epidermis. Not painful in itself, it looks the same over this little water pocket and does a great job of keeping in the fluid. In eczema, the waterproofing quality of the skin is just not as good as it could be.
In summer, when the humidity is high, eczema is not a big problem since it’s just as wet outside as in. But in the winter, when your household furnace is running and drives down the humidity to 3 percent or so, there is a big difference. Few skins can tolerate this severe challenge.
In children with eczema, this vapor barrier fails and you lose the skin’s moisture to the air. That causes the skin to shrink and lose flexibility, like old dry leather. With movement, that dry skin fractures, cracks and splits, creating more leakage and widening involvement.
The most common sites for this rash are behind the ears, elbows and knees, all areas of high movement that need flexibility to remain intact.
What to do?
First, to help your body to restore the skin’s waterproof state—most critical in winter—you can use easily available nostrums like mineral oil, baby oil, Vaseline or petroleum jelly. Make sure any moisturizer includes one of these elements. Then, apply frequently to make sure your child’s hide stays soft, flexible…and waterproof.
Wash with non-soap cleaners. Let’s not remove the natural oils in the skin that aid in this waterproofing every time we wash. Pat dry only. Rubbing damages the skin even further. The best time to apply moisturizer is when the skin is still damp or wet and has just absorbed all the fluid it can hold. You then seal the fluids in with the waterproofing agent of choice. In winter, regularly run a vaporizer/humidifier. Just raising the humidity in the home helps quite a bit.
Easily available steroid creams do help. But limit their use to severe episodes only. Long-term steroid use is not a good thing. But occasional use limits possible side effects. Always use a moisturizer even with the steroid cream.
Eczema is a basic skin problem. There will be good times and bad. But, like all basic problems, it will require appropriate care and attention until you no longer need your skin.
(Dr. Marz, a board-certified pediatrician, is supervising physician for the Town of Barnstable school system. He practices with Bass River Pediatrics in South Yarmouth.)