Poison oak's resin, called urushiol, can remain active for a very long time. When an allergic reaction occurs after contacting poison oak, the first thing to do is to wash the skin thoroughly with warm soap and water and launder any clothes that may be contaminated with poison oak. This should include towels used to clean the skin. Some soothing remedies such as showering with cool water, applying over-the-counter anti-itching cream, oatmeal baths, or baking-soda mixture may help lessen the discomfort in mild cases. If the allergic reaction is severe, one should contact a physician or go to the emergency room, and some prescription medications including topical and oral steroids may be needed to reduce the swelling and itch.