A client believes they've come into contact with poison ivy. What should the nurse recommend first?

The recommendation to take a shower immediately is based on the importance of removing the urushiol oil, which is the irritating substance in poison ivy that can cause the allergic reaction. Washing the affected skin with soap and water as soon as possible after contact can significantly reduce the chances of developing a rash and can minimize the severity of the reaction if it does occur.

Taking a shower serves as a first line of defense and is most effective when done quickly after exposure. It helps in cleansing the skin and removing any residual oil that may not have absorbed into the skin.

While applying hydrocortisone cream, visiting the emergency department, or preparing an oatmeal bath may be appropriate steps for managing symptoms or complications later on, they do not address the immediate need to wash away the irritant. Thus, taking a shower is clearly the most effective initial action.