FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine
KEY TO POISON IVY PREVENTION: AVOID SAP AND THINGS IT STICKS TO
Question: I was running my weed eater and apparently got into poison ivy, although I don't remember cutting any. The next day my legs were covered with blisters and I had a few on my face. Is there anything I can do to prevent getting poison ivy again?
Answer: Poison ivy and its close relatives, poison oak and poison sumac, cause itchy blisters in about 85 percent of those who are exposed to them. This rash is known medically as allergic contact dermatitis or rhus dermatitis, but most people simply call the condition "poison ivy." The body's reaction to the chemical urushiol -- a sticky sap found within poison ivy's leaves, stems and roots -- is what actually produces the rash. In order for this sap to get on your skin and produce a rash, the poison ivy plant must be broken. This is the reason that an allergic person can sometimes brush up against a healthy poison ivy plant and not break out. Running the weed eater, however, shreds the poison ivy plant and releases urushiol.
It is a safe guess that you weren't wearing trousers made from heavy fabric when you were trimming your yard since you have blisters on your legs. Your string trimmer could easily sling the sticky urushiol directly on your legs. Oops -- big mistake!
Once the chemical comes in contact with the skin, it begins to penetrate within minutes, but it takes from 12 hours to several days for the "poison ivy" to appear. First there is itching, redness and swelling, followed by blisters.
Contrary to myth, poison ivy can't be spread by touching the oozing liquid in the blisters!!! This liquid is not urushiol, but your body's own fluid produced as part of its reaction to urushiol. But as you know, poison ivy can be spread. If the victim gets urushiol on his or her hands, touching another part of the body -- or another person's body -- can transfer the chemical to that area. That's the reason poison ivy tends to turn up all over the body, even though the plants generally only come in contact with the exposed areas of the skin. This may be how you got the spots on your face.
Areas with the greatest exposure to the urushiol will usually break out first. Areas that have thick skin or less urushiol on them will then break out a day or two later, giving the impression that the poison ivy was spread from the first group of blisters.
It is too late to prevent this episode of poison ivy, but here are some tips to reduce your chances of subsequent outbreaks. If you suspect that you have been in contact with poison ivy or one of its cousins, the first thing to do is to thoroughly wash with soap and water. If more than 20 minutes have elapsed since the exposure, washing may not prevent the initial rash, but it can prevent you from spreading it further.
Any clothing that has come in contact with the sticky sap should also be washed promptly, too. Handle the clothes carefully, preferably with gloves, to prevent any more skin contact with the sap. Any other object that may have urushiol on it should be washed, too. This can include the fur of pet animals, garden tools, golf balls, or anything else that may have come into contact with a broken plant. But, wear gloves when you do it; otherwise, touching these contaminated objects can transfer the offending chemical to your skin and, thereby, give you another case of poison ivy.
If you're unsure of the appearance of poison ivy, oak and sumac
in its various growing conditions, you should point your web browser to: Family Medicine® is a weekly column. To submit questions,
write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine,
Grosvenor Hall, Athens, Ohio 45701. Past columns are available online at http://www.FamilyMedicineNews.org.