Unfortunately I am not a doctor or a dermatologist. I would not be able to tell you the dosage of this medication for poison ivy. Are you currently under a doctor's care?
Here is some information about poison ivy you may want to read.
Also here is a poison ivy forum where patients discuss which medications they received including Prednisone and how they worked.
Here too is a physician site where the prednisone treatment protocol is discussed.
Your best bet is to discuss this with your doctor or dermatologist. They are the best people to be able to diagnose and treat your symptoms.
Thank you for your question.
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