Skin wrinkling in cystic fibrosis.

It had been noticed that in cases of cystic fibrosis the palmar 
skin of the fingers and the plantar skin of the toes 
wrinkled very quickly when immersed in water. Almost without exception, the 
children with cystic fibrosis had noticeable wrinkling of the fingers within 
2 min of immersion in hand-hot water, whereas normal children showed 
no (or minimal) wrinkling after 10 min. This wrinkling is due 
to an excess of salt in the skin, which increases water-binding 
capacity of keratin. The test would thus appear to provide a 
simple and cheap screening method for cystic fibrosis, but one that 
may not be absolutely reliable. 