The Ivy League Itch

It creeps, it climbs. It’s shiny - or not. It’s smooth but may be notched. It’s a vine. It’s a bush. It’s on the beach, in the park, by the roadside and at the edges of fields. The little green fiend is poison ivy and it’s everywhere in the US except the far west, deserts and high altitudes. Captain John Smith named it most appropriately in 1609.

Poison ivy grows as a vine on the ground, a woody shrub or an aerial-rooted vine on shrubs, trees, poles, and, especially, fences. It lives on the edge of almost every field, forest, parking lot, or road.

Despite a distinctive pattern of three leaflets occurring alternately along the stem, this is a sneaky, unreliable plant. Leaflets are usually fairly smooth, but can be notched, and may be dull or glossy. Leaflet sizes vary from / inch to over 2 inches in length. Even leaves on the same vine can have a variety of color or shape combinations, with shiny and dull leaves on the same triplet. Near the ocean, poison ivy often has curly, waxy looking leaves. In spring, ivy leaves start out bright red. Even through summer, new leaves are shiny and reddish, while older leaves get duller.

Over half the population is allergic and millions of people have poison ivy reactions each year. The offending agent, an oily substance called Urushiol (from urushi, the Japanese word for lacquer) is found in all parts of the plant. One nanogram, a billionth of a gram, can cause a rash but the average amount is 100 nanograms. Someone who doesn’t seem allergic is more likely to develop the itch with each new exposure. It may take longer to show in first timers - 7 to 10 days.

Urushiol contaminates footwear, clothes, tools, or pet fur and remains active for a year. It can be transferred without direct skin contact, but most people get poison ivy by touching the leaves.

If exposed, rinse with lots of cold water, like from a garden hose or lake, within an hour of contact. Wash with a grease cutting dishwashing liquid instead of soap. Warm showers can be disastrous; hot water opens pores and lets the oil in. In the first six hours, washing with alcohol may help remove the oil. Clothes should be washed or dry-cleaned.

The dermatitis starts a few hours or up to a week after contact, depending on personal sensitivity, amount of exposure and the season. The plant is most potent in spring and summer. Rashes develop less often on the soles of feet and palms of hands, where skin is thicker.

Scratching doesn’t spread the reaction if the oil has been washed from the skin. Fluid from blisters also doesn’t spread the reaction. The rash breaks out in new areas because people continue to contact it - from unwashed clothes (especially shoes and laces), equipment, pets, etc. The sap is so potent, it can be passed a dozen times and the last object can still cause intense reaction. People leave an invisible "trail" and end up re-exposing themselves over a period of weeks.

Victims have tried about every conceivable substance for topical therapy: morphine, kerosene, buttermilk, even gunpowder. Everyone appears to react slightly differently to all the remedies. Applying Caladryl lotion or soaking in Aveeno Oatmeal Bath can be helpful. Benadryl, an antihistamine that may cause drowsiness, can be effective for nighttime itching. Over-the-counter hydrocortisone creams aren’t strong enough to have much effect.

Poison ivy is so well-entrenched underground, it’s almost impossible to rip out completely. It’s sure to leave rhizomes behind to sprout. Repeated cutting eventually starves out the root system, but may take years. Don’t grab the "weed-eater"- it’s a sure way to spray plant oil everywhere. The best defense may be to nuke it with residential herbicides like Round Up or Kleenup. They’re absorbed by the leaves and carried through the entire plant. Wait several days after spraying to allow time for absorption. Dispose with care - dead poison ivy still has Urushiol.

Fortunately, poison ivy sensitivity tends to decline with age. It rarely looks the same, but there’s one constant for this miserable, twining plant with an attitude. Leaves of three, let them be!