This problem of dark knuckle can sometimes be hereditary.
FADE OFF THOSE DARK KNUCKLE….Here is the perfect and most effective remedy for dark knuckle, knees elbows, feet and ankles. OUR NATURALLE DARK KNUCKLE SETS ARE 100% national products which will gradually fade off those difficult dark areas with consistent use. #Sensitive-skin

What comes in your knuckle set:

-Knuckle Scrub 
-Knuckle Cleanser
-Knuckle Cream 

Directions on how to use your Knuckle set:

Knuckle SCRUB: apply and massage gently on your dark knuckles area for 5-10minutes, rinse off with warm water
(Use 3times weekly)

Knuckle Cleanser: Soak cotton wool with cleanser swipe it over your dark knuckles area Twice daily.

Knuckle CREAM: Apply on damp hands and feet twice daily after washing or toning.

Make sure you apply your knuckle set 2-3 times a day until it clears completely.
Thanks for your support.