Poison Ivy and other plants that you just don't want to be around: Poison Ivy, Poison Oak, Poison Sumac What is the treatment for poisoning from these plants? The best approach to poison ivy dermatitis is prevention. Once it begins, the rash will usually clear on its own by 14-21 days. Treatment is directed at controlling the itching. Oral antihistamines (like Benadryl) may help the itch somewhat, but often do no more than make people drowsy. Cortisone creams, whether over-the-counter or by prescription, are only helpful if applied right away, before blisters appear, or much later, when the blisters have dried up. Compresses with cool water or Burow's solution (available without prescription) can help dry ooze faster. When the rash is severe, such as when it affects the face or causes extensive blistering, oral steroids (for example, prednisone) help produce rapid improvement. This course of therapy should be maintained, often in decreasing doses, for 10-14 days or even longer in some cases, to prevent having the rash rebound and become severe again. Patients who are given a six-day pack of cortisone pills often get worse again when they complete it, because the dose was too low and kept up for too short a time. Folklore, medical and otherwise, endorses many other agents, from aloe leaves to tea bags to meat tenderizer. These remedies are generally harmless, but are of questionable value. How can contact with these plants be prevented? Poison ivy and its relatives are often hidden among other vegetation. Even if you know exactly what they look like, it is very hard to avoid coming in contact with them. Although wearing long pants and long sleeves in warm weather may be uncomfortable, it is important to do so when you might be in contact with plants you can't see, whether you are gardening in the backyard or hiking in the woods. So-called "barrier creams" are not very effective. When pulling up weeds, those who may be allergic should make sure to tuck sleeves into gloves at all times, since sleeves tend to ride up the forearms and leave wrists and forearms exposed. If you think you may have been exposed to poison ivy, wash the skin with cool water as soon as possible. After half an hour, however, this is no longer likely to prevent the reaction. As discussed above, washing pets and clothing may also be of limited help. Attempts to desensitize people by giving them poison ivy by mouth or by injection were tried in the past but proved to be ineffective and potentially dangerous. Poison Ivy, Oak & Sumac At A Glance Most people are susceptible to the rashes of poison ivy, oak and sumac. The sap oil, called urushiol, causes the skin rash. Poison ivy is not contagious. Wash the oily sap from the skin with water and soap immediately. Avoiding direct contact with the plants can prevent the rash.