What Should You Know About Poison Ivy?
By: P. Michael Shattuck, M.D. – Community Health Network Family Physician
A common summertime skin problem is contact dermatitis most commonly caused by poison ivy. Poison ivy is a plant that commonly grows in swampy or wet areas and is common in Wisconsin. Poison sumac and poison oak are two other plants in our area that can cause identical problems. Actually these plants are not poisonous. They earned that label because contact with the skin can cause a rash. The rash is actually an allergic reaction. This problem is more common in the summer but can happen any time of year.In order to understand how this happens, we need to understand some things about how the immune system works. We have immune system cells in our skin to help fight infections. Certain allergens, like the resin in poison ivy, can sensitize the immune system cells so that they will react if exposed to the allergen through direct contact. When these cells have been sensitized, the plant resin will trigger an allergic reaction that will cause the skin to itch, swell, blister, weep and turn red where the allergen came in contact with the skin. However, the reaction will not occur immediately. It generally takes 2 to 3 days for the rash to develop which is why this is commonly referred to as a delayed hypersensitivity reaction. The rash often takes 2-3 weeks to resolve. It does resolve on its own. Some people react more severely than others.
The resin is on the leaves, branches, and roots. It can even cause a reaction in the winter when the leaves are not present. It is not unusual for hunters to develop a case during the winter while clearing lanes in the woods or swamp when there aren’t any leaves. When contact with the resin occurs, it can be spread by touching other parts of the body. Just ask anyone who has contacted poison ivy on their hands and then has to go to the bathroom in the woods. Once the skin and clothing is washed the resin will not be spread. It can be acquired by someone handling clothing that has fresh resin on it.
The best way to avoid poison ivy is to avoid areas where you suspect it to be and wear clothing to cover the skin. If you think you have been exposed, immediately remove your clothing; wash yourself and your clothing with soap and water.
If the rash occurs, it is not contagious and the fluid that drains from the blisters does not spread the rash. The rash may develop over several days and seem to spread. This occurs because the reaction will occur sooner in areas where the skin had heavier exposure and where the skin is thinner. The main symptom is itching which can be quite intense. The itching can be treated with cool compresses and antihistamines by mouth. Also, calamine or caladryl can be applied topically. Steroid medications can be used to reduce the immune response to help ease the symptoms. Topical steroid creams can help minor cases but oral steroids, like prednisone may be needed in severe cases. In the past injections were given to try to prevent poison ivy but this is not recommended at this time due to ineffectiveness.
Pictures of these plants can be easily accessed on line. Contact dermatitis due to plants is a common cause for people to seek medical attention. Do your best to avoid this problem and stay healthy my friends.