If you've ever seen the movie, "Little Shop of Horrors," you might draw a parallel to the oversized, flesh-eating plant known as Audrey II with the more prosaic leaf known as poison ivy. Unlike Audrey II, poison ivy is not carnivorous; but like it, toxicodendron radicans, can pose serious risk to those unlucky enough to be allergic to it.
To make matters worse, according to a recent report in Weed Science, poison ivy has grown more aggressive since the 1950s, with measurably increased leaf size and oil content. This is bad news if you are one of the more than 350,000 people who are stricken by poison ivy annually.
But Stamford dermatologist Debra Pruzan-Clain offers one positive fact: "One must encounter poison ivy at least twice before a reaction occurs. During first exposure, poison ivy oils elicit an immune response that is "remembered" by our skin. But when poison ivy is encountered the second time, these cells are primed to react and cause the inflammation or rash we know as poison ivy." So, just because you haven't had it yet, it doesn't mean you are immune.
Poison ivy grows throughout much of North America, and is extremely common in New England, the Mid-Atlantic, and southeastern U.S. It's typically found in wooded areas as well as exposed rocky areas and open fields, and is recognizable by its group of three leaflets on small stems coming off larger main stems. For decades parents have taught their children the singsong phrase, "Leaves of three, let it be," as a way of learning to spot this prettily toxic plant. It also sports inconspicuous greenish flowers with five petals, and berry-like fruits that are hard and whitish.
Contrary to the myth that poison ivy is stubbornly contagious well after contracting it, Dr. Pruzan-Clain says it can spread only when the oil (urushiol) is fresh on your skin. "The rash itself is not contagious, even if there are oozing blisters, but you can contract it if you touch the plant with your hand and then wipe your face. And if the oil gets on your clothes, you can spread it when you take them off. Once you've washed the oil off your skin with soap and water, however, you are no longer contagious to yourself or anyone else."
If you think you've contacted poison ivy, says Dr. Pruzan-Clain, "Wash with soap and water as soon as possible. Some studies say the oils must be on your skin for at least 15 minutes before you start to react." She adds, "You can get poison ivy from your dog or cat. Even though pets do not react to the plant, the oils can get on their fur. Fido comes in and gives you and affectionate nuzzle and now the oils are on your skin."
As to treatments, Dr. Pruzan-Clain recommends over the counter hydrocortisone and calamine creams, as well as oral Benadryl, which both help alleviate the itchy, uncomfortable symptoms. But if your reaction becomes more serious – if it is on the face or ingested – she recommends seeing a doctor, who will likely prescribe topical cortisone creams or possibly or steroids.
Dr. Pruzan-Clain offers some unexpected facts about the much-maligned perennial:
~ The rashes from poison ivy, oak and sumac all look identical, and it's impossible to discern one from the other by looking at the rash alone.
~ Mango skin also contains urushiol, so those with the poison ivy allergy might react to the fruit as well.
~ The rash of poison ivy can appear in new places for several weeks because the areas you might've brushed against the most tend to cause the quickest and most intense reaction. But those areas you brushed against less or that you spread to yourself take longer to appear and are less inflamed.
Avoiding contact with the plant is, of course, the best prevention. When you spot poison ivy, show it to kids and instruct them to stay away from it. If you have a large amount growing in your yard, consult with a professional landscaper for removal. Unless you are a professional, do not "weed whack," as it sprays the poison ivy -- and hence the oil -- right at you.
Have you encountered poison ivy? Do you have a fail-safe cure? Please let me know here, or at email@example.com.