Will washing the skin after getting poison ivy prevent a reaction?

Washing the skin immediately after contact with poison ivy can help remove the plant's oil, urushiol, which causes the allergic reaction. If done within 10-30 minutes, it may reduce the severity of the reaction or prevent it altogether. However, once urushiol has penetrated the skin, washing will not prevent a reaction. It's essential to clean the skin thoroughly and wash any contaminated clothing or objects as well.