Cures for poison ivy and oak?

Not really a "cure": Technically there really isn't a "cure". Most every patient will recover without doing anything. However, treatment certainly makes one feel a heck of a lot better in the process. Poison ivy and oak and sumac are all allergic reactions to the resin on the plants. If you are allergic (and many people are or will be) then you will have a reaction every time you have contact with the plant.

See below: mild cases can probably be treated with a steroid cream. severe cases usually require oral steroids.

Best cure is prevention. Avoid 3-leaved vines and low growing plants. Wear long sleeves and gloves. Avoid touching your face. Any plant parts (vines, leaves) should be thrown away with the garbage (don't compost them). The rash is a delayed hypersensitivity reaction and will appear after a day or two. Topical steroids or oatmeal soaks or pramoxine cream can ease the pain; may need prednisone.