Article in English: Both the leaves and the stems of poison oak contain urushiol, an oily plant substance that triggers an allergic reaction in the form of the poison oak rash. Urushiol can also be found in the roots and even in the dead plant.  In addition, urushiol can become airborne if the plant is burned and is easily transported from one object to another. The rash from poison oak is not contagious in the standard sense, but if someone has the urushiol on their hands and touches another person, that second person can react as well. All parts of the poison oak plant contain the toxin urushiol. Even when the leaves fall off in winter, the plant is not safe to touch. A rash from exposure to poison oak can vary depending on the person because some people are more sensitive to urushiol than others. In general, the rash will be very itchy and very red, with red bumps that may blister and ooze fluids. The rash can be streaky and patchy and can range from relatively mild to very severe. When you are exposed to poison oak, first rinse off any exposed area with soap and warm water as soon as possible, hopefully within 30 minutes. Also wash any clothing or tools that may have been exposed to the plant. In order to help relieve the itching of the rash, apply calamine lotion to the site. You can also apply topical steroids such as clobetasol or systemic steroids and antihistamines. Also try a cold compress or an oatmeal bath.  To make an oatmeal bath, pour two cups of oatmeal into a nylon sock or stocking and tie it onto the tap so that warm bath water runs through the oatmeal.  Soak in the tub or soak the affected areas for at least 30 minutes. You can also use baking soda in a warm bath. Be aware that urushiol can be easily passed to another person, animal, or object. Make sure anything or anybody that may have come into contact with poison oak is carefully washed with soap and water. Most rashes will heal in five to 12 days, but the rash can last as long as a month or more. Call emergency services if the reaction to the poison oak...

Summary in Vietnamese:
Tìm hiểu nguyên nhân gây phát ban. Nhận biết phát ban. Vệ sinh thân thể và giặt quần áo. Giảm ngứa. Tránh lây phát ban cho người khác. Gọi cứu trợ.