Parents.com
What it is: An allergic reaction to the oily resin in the plants' leaves. Some people are particularly sensitive to it.
What it looks like: A red, extremely itchy rash with bumps or blisters that usually appear one to two days after your child touches the poison ivy, oak, or sumac plant.
What to do: Clean the area with soapy water within 30 minutes and wash clothing to prevent spreading. Apply hydrocortisone cream or calamine lotion for itching. Call your doctor if the rash involves the face or eyes.