I am experiencing itch and skin rash over finger joints.

May be eczema: Eczema on the fingers and hands doesn't have to look like the dry, crackly surface skin texture of eczema elsewhere. Fingers can have itchy flesh-colored bumps, called dishydrotic eczema or dishydrosis. The treatment can be as in eczema, with hydrocortisone cream 3 times a day for a week... and if the rash worsens or isn't better, one should see a primary care doctor or dermatologist for care.