Alexa Fleckenstein M.D.

When we first moved to Boston, we went on a walk into the woods. I found a little vine with reddish stems and three leaves. I never had seen anything so beautiful and modest. Therefore I unearthed it, roots and all, and planted it in a pot on our roof. A few days later, my husband developed a palm-sized inflamed red patch on his right buttock. Then I got some bizarre formations with blisters on my arms – and from there, the rash went everywhere. First we thought we had bedbugs. We pulled the bed apart and sprayed everything. We cleaned and vacuumed our place (was about time!). But the lesions became more. At work, I showed my arms to colleagues, and drew a blank (!). Finally, an ER doc took one look and said (you guessed it): “Poison ivy.” Of course, I had never encountered poison ivy (Toxicodendron radicans) - there is none in all of Europe. But despite all out efforts, our rashes and itches did not go away. Weeks later, I consulted the ER doc again. He quizzed me – but we seemed to have done all the right moves. Only, the lesions were still there. He looked at me hard and asked: “You are not eating cashews every day, are you?” That was exactly what we were doing – every morning in our muesli. Cashews and poison ivy (and mangoes) are in the same botanical family, Anacardiaceae (I talked about that devious family already in connection with back pain), and eating cashews daily kept the poison ivy rash blooming. The rash-producing ingredient is urushiol. Most people are sensitive to urushiol. Here is what one can do against poison ivy (and poison oak, poison sumac): • Don’t touch your face and eyes! • Stop eating cashews and mangoes until all lesions are well healed. • Wash with soap or a commercial anti-poison-ivy product (they are petroleum-based) all exposed and affected areas twice daily initially, later once a day until no new lesions crop up anymore. • One prescription suggested using only cold water because warm water might disperse the poisonous oil even more. As much as I am a fan of cold water, there are no studies about this, and I would think that the bodily warmth will spread the oil anyway. But cold water won’t hurt, and it will relieve the itch. • For more itch relief try the inside jelly of an aloe plant (any aloe will do), or Calamine lotion. I use tea tree oil for about everything (ask my husband!), and I would probably dab it on the rash for itch relief – but I have no scientific proof that it works. Another unproven remedy is jewelweed – but if I were out in the woods and it grew nearby, I would break a stem and apply its juice. Can’t hurt. • Wash all your clothing and, if you already slept in your bed, your sheets. • If the rash spreads into your face or, worse, near your eyes, see a physician. You need cortisone immediately because poison ivy in the eyes can lead to blindness. • Don’t ever burn poison ivy – it can lead to fatal lung reactions. Pull poison ivy with gloved hands and dispose of it in plastic bags. Wash gloves and tools. Often shoes and pets carry the sticky resin. Poison ivy plants look very variable - it took me years to comfortably identify them. Better stay away from anything reddish and three-leaved!