Many factors can contribute to dark skin on your knuckles. Your darker knuckle pigmentation could be inherited. It could also be a side effect of a medication you’re taking, such as an oral contraceptive, a strong corticosteroid, or niacin.
Darker skin on your knuckles may also indicate an underlying condition that requires treatment, such as diabetes or Acanthosis nigricans (AN). This is a skin condition that causes small patches of skin to darken, thicken, and become velvety to the touch, usually near the knuckles. There are treatments available to get rid of dark-knuckles.
