I used Triamcinolone Acetonide cream to treat poison ivy. Now I have a rash on my arms, stomach and thighs. Can this be from the steroid cream?

Contamination. Although allergy to steroid is possible, it is very rare. Your continuing problem is likely from contact with articles which have been contaminated by the resin of poison ivy. Be sure to wash out everything during that outing with laundry detergent (shoes, tools, car seat etc) else it will be acting like Freddie in Friday the 13 for you.