I have two dark spots on my big toes (brownish color) - one on each 'knuckle' area of toe. skin feels slightly rough there;no pain. what is it?

Since your: skin "spots" are BILATERAL and Symmetrical I would guess that they are caused by one of the pairs of FOOTWEAR you have RUBBING on the tope of your great toes....(Often the "closest fits"is that area) Just a thought! Hope it helps!

This may be: as a result of shoe gear rubbing on the joints causing this "hyperpigmentation" - of course I can't see it, so this is just an educated guess.

Shoes, Shoes: It certainly sound like you shoes may be responsible. You need better fitting shoes of better fitting feet.