Why are the bottoms of my feet dark yellow? -

Why are the bottoms of my feet dark yellow? -

I have been trying to stop smoking for the past two months and recently have been successful finally. My husband thinks that the yellowing on the bottoms of my feet are excess nicotine coming out of my system (I smoked for 22 years), but who knows? Anyone out there know what is going on with my feet??It may be Crest syndrome. It has to do with an abnormal, thickening of the skin. There are other symptoms as well. Fatigue, stress, etc.

Why are the bottoms of my feet dark yellow? -