The primary way to distinguish between poison oak and poison ivy is by where the plant grows. Poison oak generally grows along the West Coast of the United States, while poison ivy grows in the remainder of the states, according to About.com. Both plants have three-leaflet leaves and white berries.Continue Reading
These plants, along with poison sumac, form an oily substance on their leaves known as urushiol, according to WebMD. This oil causes irritation to humans who touch the plant as well as to those who touch clothing or animals exposed to the plant. Burning any part of the plant releases urushiol as a vapor that has the potential to irritate the lungs.
Poison oak and poison ivy rash develop from contact with the oil. WebMD indicates it is impossible to develop the rash from touching the blister fluid from another person with a rash. The reaction is to the oil, which the immune system sees as a harmful substance.
The rash from all three plants is identical as the substance to which the body is reacting is the same, according to Parents. At home, treatment for the rash includes the use of cold compresses, cool baths and calamine lotion to relieve the itching. Sometimes the rash spreads and requires medical intervention. Dermatologists sometimes prescribe topical medications, including corticosteroids and anti-inflammatories to relieve the itching.Learn more about Outdoor Plants & Flowers