First Thank you all for the information provided!! Yes I take 10Mg of METHOTREXATE one day a week and the other six days a week I take mg of folic acid. The tops of my feet are dis colored. I have bumps that itch on my arms and legs and blisters in my mouth. What I need to know is what types of chemical may cause this issue. Chemicals such as Diesel oil, red lead paint, acetone and Zinc Chromate. Any types of Heavy metals use in chipping paint off of Boat bottoms and marker buoys used in sault water.