Hello, I Am Using Flouracil 5 % On My Hands

Hello, I am using Flouracil 5 % on my hands and calves to start out with...other body parts later...I have used this before and my derm doc gave me Triamcinolone Acetonide Cream for the itching.i just started my flouracil 3 days ago and already am itching really bad...can i start the steroid cream now or do I have to wait till i start blistering, etc.? thank you