Finding a poison ivy in your yard can be unpleasant. The famous rash is actually an allergic reaction to an oil on the plant’s leaves, stem, and roots called urushiol. It can appear not only on the skin where you touched the leaves but also wherever the oil spreads, though these secondary areas are likely to react more slowly and show the rash later than where you first touched the plant, even the initial rash can wait 12 to 72 hours to show up. You can also react to oil that has gotten on clothes, shoes, toys, and tools that have touched the ivy. It’s even possible to see a mild poison ivy reaction after petting a dog that has picked up the oil on its fur. The good news? This means that you can limit the reaction if you notice right away that you have touched poison ivy.
First, rinse off the skin that touched the ivy with cool or cold water–you don’t want warm water, because that will open your pores and allow the oil to get deeper into your skin, as well as helping the oil spread across the surface. Then wash the area again with soap and more cool water and rinse it thoroughly. If you can get the oil washed off in under ten minutes, you might avoid the rash completely, but even washing it off hours later can make it milder and keep you from spreading the oil around. Dabbing a little rubbing alcohol (either on its own or mixed half-and-half with water) across the skin can also make the rash milder when it appears.
Once you’ve developed a poison ivy rash, you need to keep it clean and dry. Don’t scratch–that will only make it feel worse, and you may open the skin to infection. Avoid hot water around the rash for several days. You can lay cool, wet washrags across the affected areas to help with the itching, or mix cornstarch or colloidal oatmeal into cool or lukewarm water if the rash is very large. If the itching keeps you up at night, try an over-the-counter antihistamine, hydrocortisone cream, or calamine lotion. You can also ask a doctor for steroid cream or pills, or pick up an antiseptic or drying cream or ointment labeled for use on poison ivy rashes.
It’s pretty common for your first encounter with poison ivy to be fairly mild, and for later encounters to produce more painful rashes or even anaphylactic reactions. If you have had poison ivy more than once, be on the lookout for any swelling, especially around your face and neck. If you start to have trouble swallowing or breathing, get medical help right away.