2012-07-07 / Columnists

Maintaining Your Health on Mackinac

Poison Ivy Proves Natural Biological Hazard For Woodland Adventurers
By Yvan Silva, M.D.

Summer is in full bloom. As spring sprang slowly into summer, the foliage and flora followed, likewise turning the land from scrawny to lush. As usual, when the tulips give way to daffodils, the grass gets greener and taller, roses, sunflowers, and everywhere cultivated beds of beauty begin to abound, and special to us all, nature’s rich rejuvenation of the ground cover brings out the wildflowers - yellow lady’s slipper, wild columbine, many, many others and the trilliums – of the lily family, with a whorl of three leaves from the center, bearing each a three-petaled flower. And speaking of threeleaved plants, beware of the poison ivy (Rhus radicans), the plant everybody loves to hate.

Along with poison oak and poison sumac, these plants contain a poisonous chemical, an oil-based substance called urushiol, which is contained in all parts of the plants, leaves, berries, roots, and bark and produces contact dermatitis in all who are sensitive to it. Only 10% to 15% of the adult population is truly immune to urushiol sensitivity. There is truly such a thing as first-time sensitivity that is, you’re already sensitized, although you’ve never known or thought to have been in contact with the plant. And it’s extremely unwise to believe that insensitivity to these plants is permanent.

Indeed, in a recent poll of people with personal experiences with these plants, it was found that many have a passionate attitude toward the plant and the sense of something mystical about it – that, for example, this stuff can get to you, even if you stare at it out the window. Beside the mysticism, there is a lot of confusion about what the scratching and itching is all about and why it even occurs. Not infrequently, there is humor directed to the affected sufferer, or the theatrical behavior following the reaction.

Uroshiol is an oil, which causes a rash on contact. The most common way people get poison ivy dermatitis without firsthand contact is from petting dogs and cats that romped in it. You can be exposed by touching contaminated clothing or garden tools and other objects, even years after they were in contact with poison ivy. You should never burn poison ivy plants or roots because uroshiol can be carried on smoke particles that can affect the skin and more importantly, inhaled into the lungs. A suitable herbicide must be used to destroy the plant.

What should you know, and what should you do? Avoid the plant, and don’t kid yourself that clothing yourself completely, or even wearing gloves, will protect you adequately. You can carry urushiol on these from room to room, leave it on every chair, and spread it all over the house. These very items can come back to haunt you, and particularly your skin. And if you know that you’re really hypersensitive, it’s best to carry some rubbing alcohol on your walks into the woods. If you think there has been exposure, use the alcohol, which will leach the oil from your skin and protect you for several hours. Shower after that with plenty of water.

Does it spread if you scratch the blisters? No, but scratching can lead to secondary infections. Does soap work? Not really, but the water used with it can help, and although it doesn’t neutralize the oil, enough of it can dilute it. When the rash appears, the discomfort can be reduced by preparations available over the counter or by prescription. In severe cases, antihistamines may be required to control itching, and fulminant cases require cortisone treatment, orally and/or topically to control the severity of the allergic reaction which, by the way, can last for weeks, often by repeated contact, unknowingly, with contaminated items.

Interestingly, humans are the only ones in the woods to be affected so seriously. Bears, birds, and all the other critters brush against the leaves and eat the berries, without any effects. Clearly, the best way is to make a serious effort to learn to identify the plants and avoid them. Poison ivy allergies are no fun; they can continue for days and weeks and ruin your summer.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.

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