I have a rather impressive case of poison ivy that is now 16 days past initial exposure and continuing to worsen. My doctor prescribed a hydrocortisone valerate cream for the itching. I also have an OTC hyrdocortisone cream that is billed as being “Maximum strength” at 1%. The prescription cream shows 0.2% (and also says specifically each gram contains 2mg).
Why is a prescription required for a cream that has a weaker concentration of the active ingredient? Or is it somehow fundamentally different despite that they both say hydrocortisone?
Neither one helps all that much anyway. 
(I’m also taking a course of prednisone but it’s not clear whether it’s helping–rash on the areas of exposure are improving but still itch like crazy, and I’m getting rash elsewhere that continues to worsen.)