I've been taking prednisone for 5 days out of a 12 day treatment for poison ivy. could this cause a blood clot?

Prednisone: Prednisone is routinely given for many inflammatory conditions. Usual duration for most acute conditions is 1-2 weeks. While Prednisone used long term (months-years) may cause many undesired side effects, there is a very low likelihood of getting a blood clot in the time span you are using it for unless you have underlying pathology or significant risk factors predisposing to blood clots.