Throwing a stick into the brush and having Patches bring it back is great fun for both you and your dog. Because the allergen is an oil, it's probably still on your dog's coat. To remove it, the dog needs a good bath.
Poison Oak and Urushiol
Poison oak (Toxicodendron diversilobum) is a member of the sumac family. It has a variety of growth habits, growing as a vine in shaded woodlands and as a shrub in sunny locations. When Patches brushed against poison oak vines or ran through a shrub, the urushiol oil on the leaves rubbed off onto his coat. While urushiol generally doesn't affect dogs, if you touch your dog's coat and get the oil on your hands or fingers, you may have an allergic reaction.
Play It Safe
Before bathing Patches, put on long sleeves, long pants, shoes, rubber gloves and safety goggles. While you already may have been exposed to the oils, each time you're exposed to the allergen it increases your sensitivity. Another exposure to the urushiol oil may trigger a more severe allergic reaction that can lead to bacterial skin infections, such as cellulitis.
Wiping the Dog Down
There are several outdoor skin cleansers formulated for use after exposure to poison oak. After checking the label to ensure that the product may be used on Patches, pour a generous amount onto a washcloth or rag. Wipe his entire coat and then give him a bath using pet shampoo and rinse him thoroughly. Dry him off. Wash the washcloth, towels, the clothes you were wearing and anything else he touched with laundry soap and hot water.
Pet Shampoo Works Too
Lure Patches into the bathtub, wet his fur with lukewarm water and shampoo his coat with pet shampoo. Rinse thoroughly, let the water out of the tub and repeat. After he's been shampooed and rinsed three times, dry his coat with clean towels. Avoid touching his coat until it's completely dry. Wipe down the tub and wash all the towels, rugs, washcloths, your clothes and other items that came into contact with his coat.