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Poison Ivy and the Immune Response

Poison Ivy and the Immune Response

A few weeks ago I felt incredibly lucky to be doing yard work. I usually leave outdoor chores to my husband, as I have rheumatoid arthritis. This means there are days when a sink full of dishes or a basket full of laundry is daunting enough, so maneuvering a lawn mower, leaf blower, or weed whacker seems impossible. However, I was having a “good day,” when the pain in my joints was minimal and a morning of pulling weeds felt manageable. I had a rough winter and spring, filled with infections and flares, that necessitated my husband and I operate in “survival mode.” We took care of our children, our jobs, and critical chores, but things like weeding our backyard were put on the backburner while I focused my energy on recovery.

Therefore, it was all the more satisfying to rip out the weeds that had taken advantage of my months of poor health. As I crouched among the plants, freeing them from vines and weeds, I was filled with the gratitude I always feel when my body allows me to use it fully. I felt strength and vitality flowing through me, and I was thankful for that feeling, as it isn’t possible to experience it every day.

Even better, I didn’t flare later in the day, as often happens after strenuous activity. I took a muscle relaxer at bedtime just in case, as muscle stiffness can exacerbate joint pain and I wanted to ward off potential morning agony. The next day I was not only spared a flare, but I didn’t even have the “activity hangover” of fatigue and mild swelling and pain that almost always occurs after I’m physically active. I was thrilled. However, it turned out I was not yet out of the woods in terms of paying for my day outdoors.

An exposure to poison ivy

Thirty-six hours after my morning of weeding I woke up in the middle of the night scratching all over. As the itchiness pulled me from semi-consciousness to full wakefulness, my fingertips felt bumps all over my body, and I wondered how I’d been so eaten by mosquitos without realizing it. I went to the medicine cabinet in search of anti-itch cream and saw that my legs, arms, and even parts of my neck and face were covered in an angry rash. For the first time in my life, I was having a nasty reaction to poison ivy.

How our immune system reacts to poison ivy

Poison ivy produces an oil called urushiol, which can cause an itchy and even painful rash. Interestingly, urushiol would actually be harmless if the immune system did not perceive it as a threat.1 While some substances cause immediate irritation when in contact with human skin, poison ivy symptoms do not appear for 12-72 hours after contact, when the immune system has detected the substance and, in the cases of those who are allergic to poison ivy, determines that the urushiol is a foreign invader. This leads the immune system to attack its own skin cells.

Does this sound familiar? Those of us with rheumatoid arthritis know that our immune systems have become confused and go after our joints, tissues, and organs rather than fighting germs. While researchers don’t fully understand why some people’s immune systems go rouge and fight our own bodies instead of focusing solely on viruses and bacteria, this process of “friendly fire” from our immune systems can cause a wide variety of autoimmune conditions.

However, whereas the majority of people do not suffer from this group of diseases, most individuals are prone to an immune system response to poison ivy, leading to the highly unpleasant rash. Yet, approximately 10-15 percent of the population does not develop a response to contact with urushiol, as their bodies do not interpret it as a threat that needs to be attacked.2

For 38 years I was one of those fortunate people who never had an unpleasant experience with poison ivy. Throughout my childhood and adulthood, there have been numerous occasions when my hiking or yard work companions would develop poison ivy rashes, yet I was always unscathed. Therefore, I didn’t give the plant much thought . . . until this summer.

My first poison ivy rash

My first poison ivy rash was severe. Luckily, I happened to have an infusion appointment a couple of days after it developed. By that point, I was sleep deprived from restless, itchy nights, and I had tried multiple over the counter products to no avail. I was desperate for some help. My rheumatologist added a corticosteroid to my infusion and prescribed oral prednisone as well. Having taken countless rounds of corticosteroids over the 20 years I’ve been battling RA symptoms, I took note that the same drug is used for poison ivy reactions.

I mentioned that I had previously been immune to poison ivy, and my doctor said that as my rheumatoid arthritis has been more active in recent months it’s possible my immune system has become more hypersensitive and now reacts to the plant oil.

No life-long immunity to poison ivy

The immune system is certainly mysterious, and the misdirection of my confused immune system already causes my rheumatoid arthritis symptoms in addition to making me more susceptible to infection. Finding out that it also makes me react to urushiol was a very unpleasant surprise, as for the next two weeks the painful itching in my blistered, breaking skin surpassed the discomfort in my joints.

Now that I’m aware that my immunity to poison ivy was not life-long, I will be taking far more precautions when performing any future yard work. For any readers who may likewise have been granted a respite from poison ivy response, you may want to consider taking these precautions before you ever develop a rash. Had I understood that poison ivy rash was actually caused by a confused immune system, I wouldn’t have assumed that I would always be immune to poison ivy, considering how perpetually confused my immune system is.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

  1. Poison Ivy: an Exaggerated Immune Response to Nothing Much. Poison Ivy Immunology. Accessed July 29, 2016.
  2. A poison ivy primer. Smithsonian Insider. Published December 2014. Accessed July 29, 2016.


  • VeggieSteve
    2 years ago

    HAH! I’d been on oral Methotrexate for some weeks, when Doc decided to up the ante with Otrexup injectable. Hey, NOW I’m starting to feel pretty good! So good, I decide to tackle those lousy ivy vines taking over the north side of my home. DECORATIVE ivy, may I remind you. Got rid of it all, and felt pretty accomplished, until the tingle. The SENSATION. The BUMPS. Rhus dermatitis. Which I haven’t suffered for YEARS. Even after the last time I cleared this SAME ivy.

    Then my wife says (she’s the bright one) “You’re taking an immunosuppressant! Of COURSE you’re gonna react to ivy toxins!” Oy, veh is mir. I shoulda known. Next time? I hire someone to do the weeding. Hehehe…at least my joints feel better. I can actually reach all the places that itch!

  • Tamara Haag moderator author
    1 year ago

    Hey VeggieSteve,

    Sorry for the delay in a response (I was out of town and then resting up from being out of town). Hopefully by now you are feeling much better from your ivy contact. When I think back to this episode of my own poison ivy response I shudder at the thought and am so grateful to be past that.

    I’m so glad you have a spouse who understands the immune system, as very few people do (even those of us with autoimmune conditions!). I’m also glad that you felt good enough to do the weeding and that yes, you could reach all your itchy spots! Those of us with RA/RD know this is something to celebrate!

    Thanks so much for sharing your experience, and for being in our community,

  • Karen
    3 years ago

    Thanks so much for sharing this. I have also been unaffected by poison ivy my whole life. I’ve wondered if this could be a problem, since my immune system and I are currently not on speaking terms. I’ll definitely be being more careful. (If I’m ever lucky enough to be tromping through the woods again)

  • Tamara Haag moderator author
    3 years ago

    You’re welcome, Karen! I also hope this is never an issue for you, and that you DO get to tromp around the woods again. I hope your immune system can get out of the doghouse soon. When our immune systems turn against us it just makes everything so complicated. Thanks so much for sharing!

  • Dave
    3 years ago

    Wow, Thanks for sharing. RA makes for a crazy wild ride, does it not? A couple of weeks ago I had a bad encounter involving a tractor/bush hog and a yellow jacket nest. I wound up with a huge bruise every where I got stung. I had never had that kind of reaction before. Who knows what takes place with our bodies with all the meds that suppress an immune system that is messed up to begin with. I will certainly be careful with the poison ivy!!

  • Richard Faust moderator
    3 years ago

    Hi Dave, sorry to hear about the bee stings. As allergic reactions often get progressively worse (bees in particular, take it from someone with this particular allergy) it may be useful to talk to your doctor or an allergist about this reaction. Hope your doing better. Best, Richard ( Team)

  • Tamara Haag moderator author
    3 years ago

    Hi Dave, Thank you for sharing. That sounds horrible about the yellow jackets, and it does indeed make one wonder what’s exactly happening in these mixed-up bodies of ours. I hope you’ve recovered!

  • janlorraine
    3 years ago

    This happened to me a few years ago. After trying every anti-itch cream in the drug store, I finally heard about a prescription only medication called fluocinonide or lidex. It makes the rash dry up and go away very quickly. I recommend it highly. I hope you get better soon.

  • Tamara Haag moderator author
    3 years ago

    Thanks so much for sharing that tip, and for the well wishes!

  • Carla Kienast
    3 years ago

    Tamara: I am so sorry. As a kid I had a severe reaction to poison oak that got into my bloodstream. I was a mess from top to bottom! Your post really illustrates that your body can develop a reaction to any substance at any time. This occurs, for example, to people who take aspirins and antibiotics their entire lives only to wind up one day in the hospital with an anaphylactic reaction. Sorry you had such a reaction!

  • Tamara Haag moderator author
    3 years ago

    Thanks Carla! Yes, our immune systems are certainly capricious!

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