Hi-Have become aware in the last few weeks of a darkening (blackish) area on several of my knuckles. The skin is also thicker and seems scaly. I am a 61 yr.old female who had eczema as a baby. I am being treated for high blood pressure and underactive thyroid, and take RX meds for pain. I should also mention that my fingers may begin to itch terribly to the point that I break the skin scratching. It may also help to know that I have cats so handle litter. Have been checking online myself-am really worried about the possible link to diabetes, for which I am regularly tested and have had no problem with thus far. Thoughts?