It's a question we are often asked. Folks that adventure or work in the outdoors may have been exposed to poison ivy or oak and want to know what to expect. Others have broken out and are trying to determine if their rash is from poison ivy, oak or sumac plants.
Poison oak, ivy, and sumac all contain the same rash-causing allergen, urushiol (pronounced: oo-roo-she-all). Urushiol is a potent substance found in all parts of the plant including the leaves, stem, and even the roots. A little bit of this oil goes a long way; it is incredibly powerful!
Urushiol does not evaporate, and exposure can occur from direct or indirect contact. It can last on items such as tools, clothing, gear, fences, pets, etc. for months, even years. This makes it possible to develop a rash the next time you encounter these items.
Sensitivity to urushiol develops over time and can increase as a person has more contact. It isn't uncommon for an individual to go without a reaction to poison ivy or oak, and then one day develop a rash.
A poison ivy rash can appear anywhere from 24-36 hours after exposure, and last between 2 to 4 weeks. How quickly symptoms appear, and the duration of your rash depends on a few factors:
Rashes and what they look like vary from person to person. Symptoms can include intense itching, redness, swelling, or blisters. It is important to never break the blisters, as it may cause an infection. The liquid that oozes from the blisters often dries to form a yellow crust-like substance. It's best to leave the rash uncovered to allow oxygen to aid the healing process. However, if the blisters ooze excessively, use a loose bandage to cover the area.
Contrary to popular belief, you cannot "cure" a poison ivy or oak rash. You must let your body run its natural course. However, there are products you can use to help ease your symptoms (itching, redness, inflammation, etc.).
Seek immediate medical attention if: