# Poison Ivy exposure **URL:** \ **Category:** Factual Questions\ **Created:** [June 5, 2011, 3:29pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400 "2011-06-05T15:29:23Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![No\_umlaut\_for\_U](https://avatars.discourse-cdn.com/v4/letter/n/ea5d25/32.png) [@No\_umlaut\_for\_U](https://boards.straightdope.com/u/No_umlaut_for_U)\ **Post date:** [June 5, 2011, 10:08pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/21 "2011-06-05T22:08:47Z")
Out of curiosity, how would you be treated for lung/poison ivy exposure? Steroids? ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [June 5, 2011, 10:16pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/22 "2011-06-05T22:16:57Z")
> [@TriPolar](#): > > This thread reminds me of the situation I have a hard time comprhending. Apparently some people have difficulty identifying poison ivy. I can pick it out at a glance. The slightly reflective dark green color of the leaves seems like a warning from mother nature to stay away. The three leaf formation is common, but not always apparent, but the color of the leaves is a dead give-away. Maybe be my funny blue-green color discernment makes this easy for me, but I’m surprised at the number of people who claim they can’t identify poison ivy. Does anybody really have this problem, or is it an excuse for a lack of caution? The problem is that there are many different kinds of poison ivy with differing shapes. The three-leaf part is as good enough a rule as any. My wife got it all over herself a few years back, and we didn’t have a clue what it was and she went to the doctor for treatment of the mystery rash. Then a friend was visiting and pointed out huge quantities of poison ivy all over our back yard. Thing is, the leaves looked nothing like what I remembered learning about in scouts as a kid in Michigan. The poison ivy we seem to get in my corner of Jersey has odd looking asymmetric leaves, while the stuff I learned about as a kid had shinier leaves that were more maple-leaf shaped. ---
**Author:** ![thelabdude](https://avatars.discourse-cdn.com/v4/letter/t/dc4da7/32.png) [@thelabdude](https://boards.straightdope.com/u/thelabdude)\ **Post date:** [June 5, 2011, 11:01pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/23 "2011-06-05T23:01:43Z")
Yes, the crap varies. One lady was trying to tell me anything with 3 leaves was poison ivy. I pointed out strawberries. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 5, 2011, 11:53pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/24 "2011-06-05T23:53:03Z")
I apparently have no reaction to poison ivy, but did get a rash from Virginia Creeper last week. ---
**Author:** ![Azeotrope](https://avatars.discourse-cdn.com/v4/letter/a/0ea827/32.png) [@Azeotrope](https://boards.straightdope.com/u/Azeotrope)\ **Post date:** [June 6, 2011, 12:09am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/25 "2011-06-06T00:09:23Z")
A field test for poison ivy is, while wearing gloves, crush up a leaf and rub it on a piece of white paper. Real poison ivy with turn the paper brown. Also, one field characteristic that seems to be more consistent than leaf color/shininess or shape is the middle leaflet will be on a slightly longer stalk than the side leaflets, or the side leaflets will be stalkless. I looked at the picture in your OP and yup, that’s the real stuff you got right there. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 6, 2011, 1:47am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/26 "2011-06-06T01:47:58Z")
> [@Chronos](#): > > Quoth **Tripolar** :Are you sure? Have you ever tested this ability against some definitive test? It could just as well be that you’re consistently identifying some other plant as poison ivy, in addition to the real stuff. How would you know? False negatives would be pretty obvious, as you’d get a rash from them, but false positives would presumably go undetected, since if you think it’s poison ivy, you’re not going to touch it to be sure. If I’ve identified it as poison ivy, and I or someone else had contact with it, there were always consequences. I’ve known a few people who didn’t ever react to poison ivy, but when they were around the stuff someone else (usually me) ended up with the rash. As for false positives, it’s likely, because I’d stay away from it and warn others. But the cases where people thought I was wrong and touched it anyway, or already had contact resulted in rashes for them. So I have not done a scientific study, and I’m sure you could find a plant that seems to be poison ivy in my eyes, but isn’t. But several people have told me that they can’t identify it, or wondered where they got a rash because they haven’t been around poison ivy, while I could see they were standing in it. > [@ladyfoxfyre](#): > > That’s funny, I can pick out poison ivy fairly easily but I would never describe the leaves as dark green. Maybe poison oak is darker, but the plant I always identify as poison ivy is relatively [light green.](http://mri.usd.edu/watertrail/FieldGuide/images/Other%20Plants/poison-ivy.jpg) That picture was taken in bright light and that’s how the leaves would often appear under those conditions. But in shade, where poison ivy seems to thrive, the color appears darker and much more distinctive to me. In those conditions the leaves always seem slightly shinier that other leaves of the same color under the same lighting. When I see poison ivy I’ll look at the leaves from different angles to see how the color looks. Nothing else I’ve seen with the general shape of those leaves and the right color has proven out wrong. But note my response to\*\* Chronos\*\*, I’m not conducting tests in a laboratory. Oh yeah, sometimes it’s not green at all (I think), but when I see red and brown leaves that have the right shape and pattern, there’s always been some green ones around. Those might be some false positives, but in cases where I didn’t rely on color. > [@minor7flat5](#): > > The problem is that there are many different kinds of poison ivy with differing shapes. The three-leaf part is as good enough a rule as any. > > My wife got it all over herself a few years back, and we didn’t have a clue what it was and she went to the doctor for treatment of the mystery rash. Then a friend was visiting and pointed out huge quantities of poison ivy all over our back yard. > > Thing is, the leaves looked nothing like what I remembered learning about in scouts as a kid in Michigan. > > The poison ivy we seem to get in my corner of Jersey has odd looking asymmetric leaves, while the stuff I learned about as a kid had shinier leaves that were more maple-leaf shaped. That’s why I rely on the color. I don’t know exactly how to describe what I see, but it’s green, it seems shiny, but doesn’t reflect light the way I would expect with other plants. But the pattern of the veins, the general shape, and the 3 clustered leaves make an easy confirmation. > [@DSeid](#): > > Poison Ivy (Rhus) is a [delayed hypersensitivity reaction](http://emedicine.medscape.com/article/136118-overview), not an immediate type like most other contact reactions. The response is mediated by T-cells rather than antibodies and typically takes days to appear after exposure (and can then come out over several days). A week would be unusually long, but not unheard of. Now that’s some interesting information. I have noticed that the reaction usually occurs many hours after exposure, and for myself not until the next day. I’ve heard people say they believe they got the oil on their clothes, but didn’t transfer it to their skin until days later. But your explanation makes more sense because it resolves the lack of immediate reaction as well as long delays. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [June 6, 2011, 2:05am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/27 "2011-06-06T02:05:34Z")
> [@TriPolar](#): > > This thread reminds me of the situation I have a hard time comprhending. Apparently some people have difficulty identifying poison ivy. I can pick it out at a glance. The slightly reflective dark green color of the leaves seems like a warning from mother nature to stay away. The three leaf formation is common, but not always apparent, but the color of the leaves is a dead give-away. Maybe be my funny blue-green color discernment makes this easy for me, but I’m surprised at the number of people who claim they can’t identify poison ivy. Does anybody really have this problem, or is it an excuse for a lack of caution? Hmmm. I’ve been on both sides of this. When I first moved south, I knew we had poison ivy on our property. I worked very hard to figure out which one it was. The trouble is that the shape of the leaf is highly variable. Sometimes it has a little thumb,sometimes it doesn’t the leaves can vary in size a lot. I don’t think that the color is even consistent, so I don’t know why you say it is. I very vividly remember the day I learned to identify poison ivy. I was looking at a very young plant early in the spring. The leaves were actually a bit red. The next minute, I looked around, and saw it all over. I can definitely identify poison ivy very easily. I’m just not certain how. ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [June 6, 2011, 2:16am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/28 "2011-06-06T02:16:14Z")
> [@Antigen](#): > > I’m looking online to see whether I’m in the clear because it’s almost 24 hours later now and I’m not noticing anything on my skin, and some pages say it can take up to a week for the rash to show up. To be on the safe side, for a few more days, you might want to wear clean tube socks over your hands while masturbating. ;)🆒 ---
**Author:** ![Antigen](https://avatars.discourse-cdn.com/v4/letter/a/848f3c/32.png) [@Antigen](https://boards.straightdope.com/u/Antigen)\ **Post date:** [June 6, 2011, 2:18am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/29 "2011-06-06T02:18:46Z")
Still no apparent rash or irritation, which is encouraging! I went out and tackled some more of the stuff today, being more careful about covering up and washing up afterwards. Is a normal run through the washing machine enough to take care of the oils on my clothes and garden gloves? Should I run an empty load to clean out the machine before doing normal laundry? Just for fun, here’s my yard: [Before](http://1.bp.blogspot.com/-YXbQdqhZUDY/TerLVI28i5I/AAAAAAAAAZI/rlKca5YQP40/s1600/img_1525.jpg). [After](http://2.bp.blogspot.com/-EbF9EKEs26k/TewZMnN5ahI/AAAAAAAAAZo/NNewRV-fOTs/s1600/img_1545.jpg). ---
**Author:** ![2gigch1](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/2gigch1/32/3313_2.png) [@2gigch1](https://boards.straightdope.com/u/2gigch1)\ **Post date:** [June 6, 2011, 11:42am UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/30 "2011-06-06T11:42:02Z")
Nicely done. ---
**Author:** ![Kiber](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiber/32/317_2.png) [@Kiber](https://boards.straightdope.com/u/Kiber)\ **Post date:** [June 6, 2011, 2:14pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/31 "2011-06-06T14:14:27Z")
Just to share my experience. My first significant exposure occured on a Sunday while cleaning up in my yard. I experience some mild itching over the next few days, but the serious rash didn’t pop up until Thursday. Subsequent exposures have sped up the process to where I’ll break out within a day now, if exposed. In terms of getting rid of it - I’ve found that pulling it up typically isn’t enough. Apparently even a tiny shred of the root system is enough to get sprouts poping up in short order. I’ve adjusted my irradication system accordingly. I now start by spraying it with some Poison Ivy Killer-type stuff first. I then give it a few days to act on the entire plant, including the roots. Once the leaves are shriveled and obviously dead - I then go through and pull everything up. But I always kill the plant first, and then remove the corpse. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [June 6, 2011, 2:38pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/32 "2011-06-06T14:38:29Z")
Last weekend we were kayaking a local river. My gf stopped for a pee break. She went ashore, urinated, and returned. She mentioned that the ground was covered with poison ivy, so she got into the river and went for a short “cleansing” swim. The next morning she awoke with an itchy rash on her feet/ankles. A few years ago I helped a local community pool with a beautification project. I brought my weedwacker. I wore gloves, long pants, long-sleeve shirt, face mask, etc. Two other guys on the weed whacking crew arrived in bathing suits. They laughed at me, asking if I didn’t realize we could swim after working (it was a 95 degree day). Two days later, I had some poison ivy on my neck, where my shirt was open. One of the bathing suit guys ended up hospitalized, the other guy missed a few week of work. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [June 6, 2011, 2:59pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/33 "2011-06-06T14:59:49Z")
rotary weedwackers fling plant material everywhere. you make a 6 to 10 foot (minimum) radius of plant material. plants that aren’t ivy plants in that area would be contaminated for a while. people within 15 feet of you would get poison ivy material on them. even swinging fixed blade weed cutters will fling material. chemicals (like glyphosate) on the leaves or a small hand pruner shears (prune back leaving some leaves to treat putting chemicals on the remaining leaves) are the best way for remove. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 6, 2011, 3:10pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/34 "2011-06-06T15:10:46Z")
> [@johnpost](#): > > chemicals (like glyphosate) on the leaves or a small hand pruner shears (prune back leaving some leaves to treat putting chemicals on the remaining leaves) are the best way for remove. For how long does a dead plant retain the oil? How long afterward is it hazardous to burn? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 6, 2011, 3:52pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/35 "2011-06-06T15:52:07Z")
> [@carnivorousplant](#): > > For how long does a dead plant retain the oil? How long afterward is it hazardous to burn? It will decompose pretty rapidly after it dies. I don’t ever clear the stuff after killing it. It’s brown and dead in a week. Decomposed a couple of weeks later. Also, pulling it up may stop the herbicide from working its way through the root system (but I’m not sure how that works). And to be safe, just don’t ever burn it. ---
**Author:** ![Kiber](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiber/32/317_2.png) [@Kiber](https://boards.straightdope.com/u/Kiber)\ **Post date:** [June 6, 2011, 3:57pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/36 "2011-06-06T15:57:27Z")
> [@carnivorousplant](#): > > For how long does a dead plant retain the oil? How long afterward is it hazardous to burn? Well - according to [this](http://poisonivy.aesir.com/view/fastfacts.html) site, 1 to 5 years. Most other sites I’ve seen say months to a year or longer. So - quite a while. Which is why I definitely pull it up after it’s dead. ETA: This [Wiki](http://en.wikipedia.org/wiki/Toxicodendron_radicans) link seems a bit more definitive, and also says several years. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 6, 2011, 4:08pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/37 "2011-06-06T16:08:26Z")
Quoth **TriPolar** : > [@](#): > > If I’ve identified it as poison ivy, and I or someone else had contact with it, there were always consequences. I’ve known a few people who didn’t ever react to poison ivy, but when they were around the stuff someone else (usually me) ended up with the rash. > > As for false positives, it’s likely, because I’d stay away from it and warn others. But the cases where people thought I was wrong and touched it anyway, or already had contact resulted in rashes for them. Ah, OK, I don’t usually hang out with the sort of folks who, if someone says “That’s poison ivy”, feel obliged to prove them wrong. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 6, 2011, 4:31pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/38 "2011-06-06T16:31:29Z")
> [@Chronos](#): > > Quoth **TriPolar** :Ah, OK, I don’t usually hang out with the sort of folks who, if someone says “That’s poison ivy”, feel obliged to prove them wrong. I try not to either. I’m surprised by the people who wouldn’t just be overly cautious in that circumstance. I brought this up not because I’m bragging about my skill in identifying poison ivy, it’s a common ability. I just don’t understand how people say they can’t identify it at all. Perhaps they’re just going to ignore any indications anyway, for other reasons I don’t understand. ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [June 6, 2011, 6:14pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/39 "2011-06-06T18:14:00Z")
Antigen says: [Snip] “So nuking it from orbit seems to be the way to go.” It’s the only way to be sure… 🙂 ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [June 6, 2011, 6:25pm UTC](https://boards.straightdope.com/t/poison-ivy-exposure/584400/40 "2011-06-06T18:25:00Z")
To address a couple of questions upthread, I once contacted poison ivy while gardening and had no reaction at all for a couple of days, then a mild rash, and by the end of two weeks it had covered my forearms and itched unbearably, and was spreading to my torso. I suppose it is possible that the oil on my arms washed onto my torso in the shower, but I have also heard that the reaction can show up in places that did not have direct contact (heard this from a friend who said his uncle the doctor told him that, not exactly a scholarly cite). I saw a doctor and was put on a course of steroids. I suppose the same treatment would be used for inhalation. [Previous page](https://boards.straightdope.com/t/poison-ivy-exposure/584400.md?page=1) [Next page](https://boards.straightdope.com/t/poison-ivy-exposure/584400.md?page=3)