Hi,
Wrinkles on the skin of knuckles is normal.However the pigmentaation is probably due
to extremely dry skin or a reaction
to friction.The
wrinkles might appear more prominent to you due to the dryness of the skin.
Hyperkeratosis is a thickening of the skin that occurs to protect it against rubbing, pressure and irritation. It is due to excessive accumulation of keratin in the outer layers of the skin.
The majority of the forms of hyperkeratosis are painless.