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

CONTACT WITH URUSHIOL HAS READER "CLIMBING THE IVY WALL"

Question: I get poison ivy every summer. I avoid the plant whenever I see it, but I still manage to get it. Why do I have such problems and some people don't?

Answer: Poison ivy and its close relatives, poison oak and poison sumac, cause itchy blisters in about 85 percent of those who are exposed them. You are obviously a member of this "suffering majority" rather than part of the other lucky 15 percent.

The "poison plant" rash is caused by a sticky chemical, urushiol, that is found within the plant's leaves, stems and roots. In addition to getting urushiol on the skin by directly touching the plant, urushiol can be carried on the fur of pets, garden tools, golf balls or anything else that comes in contact with a broken plant. It is also released when the plant is burnt, so the smoke is as dangerous as rubbing against the leaves. So, it is possible to get the urushiol on you without actually touching a poison ivy plant.

Once the chemical comes in contact with the skin, regardless of the method of delivery, it begins to penetrate in a matter of minutes. But, it takes 12 hours to several days for the allergic reaction, commonly called poison ivy, to appear. It develops with redness and swelling, followed by itchy blisters.

Contrary to myth, poison ivy can't be spread via the oozing liquid in the blisters. This liquid is your body's own fluid, and it does not contain urushiol. Instead, it is produced by the body as a reaction to urushiol. But as you know, poison ivy can be spread, and here's how it usually happens: The victim gets urushiol on the hands and then transfers the chemical by touching another part of his or her own body or another person. These "secondary areas" usually get less urushiol so they break out a day or two later, as do areas that have thick skin. This gives the impression that the poison ivy was spread by the "ooze" from the first group of blisters. That's also 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.

Question: What can I do to prevent getting poison ivy?

Answer: Avoiding the offending plants and things that may be contaminated with poison ivy sap is the only sure way. If, however, you suspect that you have been in contact with poison ivy or its cousins, poison oak or poison sumac, the first thing to do is thoroughly wash the exposed areas with soap and water. If more than 20 minutes have lapsed since the exposure, washing may not keep the initial rash from developing, but it can prevent you from spreading it further.

If your clothing has come in contact with the sticky sap containing the urushiol, it should be washed promptly. Handle the clothes carefully, preferably with vinyl gloves, to prevent any more skin contact with the sap.

Question: What's the best treatment for poison ivy?

Answer: Avoidance! But once it is too late for avoidance to work, there are things that may shorten the course of the rash and itching. Mild cases of poison ivy may require no more than a wet compress moistened with aluminum acetate solution (sold as Burow's solution or Domeborro solution) or soaking in cold water to relieve the itching. Calamine lotion may be soothing, too, but avoid other home remedies. They often worsen the damage to the already irritated skin. There are several non-prescription medications on the market, like calamine lotion, that can dry up blisters. However, the over-the-counter, 1 percent hydrocortisone creams are not strong enough to be of much value for this purpose. Your pharmacist can point you to the best products for the treatment of mild poison ivy. Severe cases particularly those involving the face, eyes, hands, or genitals should be referred to your family physician or dermatologist for proper care.

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.