Cameron Kerr, of King's High School, asks :-

Why do the ends of my fingers go wrinkly when washing dishes?

Bruce Turnbull, a dermatologist at Dunedin Hospital, responded.

Our skin is composed of two layers. The inner layer is soft and is composed of fibrous tissue and blood vessels. The outer layer is not unlike a rock wall when seen under a microscope. It is composed of cells which reduce in size and flatten out until finally they flake off as tiny flat discs. If we look at the skin of our fingers we can see the typical finger print pattern which we call dermatoglyphics.

When the skin is immersed in water for a long time the upper flat layer of cells in our epidermis absorb water and swell. This increase in size accentuates the normal finger print pattern and also causes new wrinkles as the outer layer of cells has become larger whereas the inner layer has not. We can liken this to a carpet which has been lifted and cleaned and during the process has stretched. When placed back on the floor on the original underlay it will be wrinkled.

This happens to anyone who immerses their hands in water for some time, for example swimmers and sub-aqua divers. This is completely normal and the skin soon returns to its usual state when allowed to dry out.