Why does your skin wrinkle when you get out of a shower or bathtub? — Grace Seymore, Ortonville, Michigan

Dear Grace:

After spending about half an hour soaking in a nice, hot bathtub you look down at your hands and feet and realize that you have been attacked by a case of wrinkly, raisin skin. Especially the tips of your fingers and toes have shriveled up like prunes. What happened to your skin to make it wrinkle?

Your skin is made up of two layers. The outer layer is called the epidermis and the lower level is the dermis. The outer layer (epidermis) produces an oily substance called sebum. You can see this substance when you touch a window or mirror and your "oily" fingerprint is left there. One job sebum does is it keeps water out of your skin—a job that it does very well. However, after long periods of time in a swimming pool, shower, or bathtub, much of the sebum is washed off and your outer layer of skin starts to absorb water. As it absorbs water it swells, but since the epidermis is "tied" down to your dermis in certain spots, it expands more where it is not "tied" down and this causes your skin to wrinkle. The difference between your skin and a raisin is that raisins wrinkle because they shrink, but your skin wrinkles because it is getting bigger.

But, don’t worry. Once you get out of the pool or tub, the water that your skin absorbed will evaporate, your skin will return to its usual size, and you body will produce more sebum. Your fingers and toes will be back to normal in no time. Isn’t your body amazing? Let’s remember to thank God for giving us such well-designed bodies.