What Causes Itchy Red Rashes On Hands?

I have had an itchy rash on tops of both hands and part of both arms for the past 4-5 weeks. The rash is always visible but not always red or itchy. It becomes red and then itchy and then will calm down and the redness will fade somewhat. I have non-hodgkins lymphoma but am not currently being treated, am doing watchful waiting. Could this be connected?