Read the information from the US Food and Drug Administration website about poison plant rashes.Poison ivy and other poison plant rashes cannot be spread from person to person. But it is possible to pick up the rash from plant oil that may have stuck to clothing, pets, garden tools, and other items that have come into contact with these plants. The plant oil lingers (sometimes for years) on virtually any surface until it is washed off with water or rubbing alcohol.The rash will occur only where the plant oil has touched the skin, so a person with poison ivy cannot spread it on their body by scratching. It may seem like the rash is spreading if it appears over time instead of all at once. But this is either because the plant oil is absorbed at different rates on different parts of the body or because of repeated exposure to contaminated objects or plant oil trapped under the fingernails.