What work best to treat poison ivy or oak?

Corticosteroids. First, you must avoid the exposure and wash all clothing and tools that might have the sap on them as the sap can be active for up to 6 months. Mild cases can respond to topical steroid creams but more extensive or severe cases need oral corticosteroids. Poin ivy on the eye can cause blindness and needs to evaluated and treated by a physician immediately. Antihistamines will not clear the rash.