The skin on your palms and the soles of your feet is one of the few places on the body that never grows hair. So when a young woman with a rare autoimmune disease twice grew fine, downy hairs on the pad of her thumb, her doctors wrote it up as a finding they had not seen described before.
The case, published March 27 in the journal Medicine, raises a bigger question than one patient can answer. Is hairless skin truly incapable of making hair, or is hair growth there simply being switched off? A separate line of mouse research points toward the second answer.
