FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

Dr. Wolf offers tips to reduce your risk of POISON IVY

Question: I got poison ivy several times last summer and I've gotten a few spots of it already this year. I'm not even sure where I get it. Is there anything I can do to prevent getting this annoying rash again?

Answer: Poison ivy and its close relatives, poison oak and poison sumac, have the potential to cause itchy blisters in about 85 percent of those who are exposed to it. Obviously, you are included in this large but unlucky group. The poison ivy rash is known medically as allergic contact dermatitis, but the fancy name doesn't make it itch any less.

The body's reaction to a chemical in the plant called urushiol -- found within the leaves, stems and roots -- is what actually produces the rash. In order for this chemical 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.

Unfortunately, very small breaks caused by insects or other minor damage to the plant will let the urushiol onto the plant's surface. You can sometimes see the evidence of this as small black spots on the leaves of a poison ivy plant. In other words, these spots are actually urushiol that has oozed through a damaged area of the leaf.

Besides directly touching a poison ivy plant, it is possible to indirectly come in contact with urushiol. It is sticky, so it can be carried on the fur of animals, garden tools, golf balls or anything else that touches a broken plant. Handling these objects will transfer the offending chemical to your skin. Perhaps this is how you've gotten poison ivy.

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 hands or other exposed areas of skin.

The area that has the greatest exposure to the urushiol will usually break out first. Areas which have thick skin or less urushiol on them will then break out later -- up to two weeks later -- giving the impression that the poison ivy was spread from the first group of blisters.

The best way to prevent poison ivy is to avoid it and its cousins in the first place. Learn what they look like in your area because the appearance of poison ivy, oak and sumac vary depending upon their local growing conditions. It helps to wear long sleeves, long pants and gloves to limit the amount of exposed skin when you are working in areas where you are likely to encounter this obnoxious weed. Using non-prescription products such as Ivy Block and Stoko Gard (available at most garden centers) can also reduce the risk of developing a rash.

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. Any clothing that has come in contact with the sticky sap should also be washed promptly. Handle the clothes carefully, preferably with gloves, to prevent any more skin contact with the sap. If more than 20 minutes have elapsed since exposure, washing may not prevent the initial rash, but it can prevent you from spreading it further.

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.