What Causes Dryness And Darkening Of Fingers And Knuckles

Hi, my fingers and knuckles (on both hands) are red and they are darker than the rest of my hand. The skin is dry as well. I realise that it s red and dry because I wash my hands all the time, but I don t understand why it s darker than the rest of my hand. I ve read that it could be a result of CO poisoning. Could that be true?