I'm no expert on this by any means outside an experience I had with poison ivy, so please take this lightly. I spent a day tearing down poison ivy off of my Aunt's house some years back. Sure enough, even after a very intense showering afterwards, I still had poison ivy on my arms, legs and stomach. My father spoke of a doctor that he knew that had a found a way to eliminate the instant urge to scratch the poisonous infection. I was completely skeptical about doing this very odd and unexpected remedy to keep your scratching down, but am guaranteed to try it should I ever get poison ivy again. Stick with me, because this really is very strange lol.
Buy dry Tide laundry detergent, but it MUST be regular Tide. NOT Tide with bleach, or Tide with anything at all, but regular Tide ONLY. Mix it with water so that it is creamy like creamy peanut butter, or if you have ever installed ceramic tile in your shower or flooring, the same style then of mixing tile grout. After your mix is complete, place it on the affected area but be ready! For a second or two, it will burn! After that, you will no longer feel the desire to scratch the area, and additional application of this mix may be necessary. I know it sounds odd, but it really worked for me, as odd as it may seem
