View Full Version : Rash-causing plants

06-04-2008, 06:34 AM
I'm hoping to find a plant/mold/fungus that is relatively uncommon (but still found) in North America that causes a distinct rash or other symptom in some or all people, whether on its own or when combined with something else (another plant, sunlight, chemicals, whatever).

Anyone have any ideas?

Basically, I need something that would enable the reader to know with relative certainty that a certain character must have been in a specific place (a specific part of an elaborate garden), so I need it to be a rash (or whatever) that could be caused only by the specific plant, and I need it to be a plant that is uncommon enough that it could be reasonably assumed he came into contact with it there and not in his own backyard.

Also, the story is set in the 1920s, so it would need to be identified with means no more sophisticated than what would have been available to doctors at the time.

Any help would be greatly appreciated!

06-04-2008, 06:57 AM
Maybe "stinging nettle" although despite its pain and itch, the actual rash may be minor.


06-04-2008, 07:03 AM
I could name several plants that could cause a rash (ginkgo, okra). The trouble is having a rash that could only be caused by a specific plant. That's almost a specialist medical question.

06-04-2008, 07:15 AM
Maybe some of the plants that have seeds that stick to your clothes would work also.

06-04-2008, 07:47 AM
Well, I know for a fact that if you try to eat skunk cabbage it causes a very nasty rash on your tongue.

06-04-2008, 07:49 AM
Poison Ivy? Or is that too common?

06-04-2008, 08:36 AM
Would the person figuring out the source of the rash already know that the infected person had been in the garden? If so, a domenstic plant like poison ivy (as suggested above) could work - though it is unlikely to be found in a well maintained garden. Same goes for poison oak, plus it is found mainly on the west coast.

If your story takes place close enough to the Mississippi, you might want to try poison sumac. The tree looks nice enough that an adventurous gardener might put one in the corner of a nice garden. Check out the info in Wikipedia - http://en.wikipedia.org/wiki/Poison_sumac

If you need someone to deduce not only that the infected person was afflicted by the plant in question, but also that the plant could only be found in that particular garden, then I think you'll need an exotic plant. And I can't help you there.


06-04-2008, 08:42 AM
An Australian native, Grevillea (there are thousands of varieties) is well-known for causing a rash in a lot of people. I suppose a keen 1920's horticulturalist would be able to collect one. They have pretty, bird-attracting flowers and all kinds of foliage depending on what area they grow in, so would probably be something that a keen collector would like to have in their garden.

Sandi LeFaucheur
06-04-2008, 01:35 PM
Rue will cause a rash when combined with sunlight.

06-04-2008, 09:07 PM
Awesome suggestions!
Thank you all.

06-05-2008, 01:57 AM
Not so much a plant, but Limes!!! Some lime juice combined with the UV rays from the sun can temporarily cause lightening of the skin. It starts off red and rash like, then lightens the pigment. Lasts up to 60 days in some cases.

Check it out...


06-05-2008, 08:09 AM
This reminds me of a "Diagnosis Murder" episode where a specific character had an allergy to roses which showed that she must have been near the rose bush where the murder took place.

Tsu Dho Nimh
06-06-2008, 03:05 AM
Where does this story take place?

06-06-2008, 03:59 AM
Anything your protaginist is allergic to would cause a rash: poison ivy, poisonoak, poison sumac. Anything in the solanaceous family: tomatoes, potatoes, eggplant, rhubarb, peppers. I've known some people to be allergic to pine tree sap or to the skin but not the fruit of mango & kiwi.

Maui Author
06-06-2008, 06:09 AM
What about mangoes? The sap of the tree and even the skin of the fruit can produce a rash very similar to poison oak. And not everyone has mango trees in their yard.

06-06-2008, 06:24 AM
Consider bishop's weed...it causes a rash similar to poison ivy, but is used in gardens as a decorative element. You could have it only in the specific garden you're targeting, perhaps in addition to the rash your character finds a leaf as well...Google it, there is lots of info on the web about it (especially about how hard it is to get rid of :))

06-06-2008, 07:22 AM
I just read a novel in which something called jimsonweed played a key role. To touch it causes rash, it can be smoked with side-effects similar to those of marijuana, and to ingest it can be fatal.

Here's some info:

Jimsonweed (http://www.vet.purdue.edu/depts/addl/toxic/plant36.htm)

06-06-2008, 08:01 AM
The trouble with your scenario is needing a rash that can only be caused by a specific plant. Face it, contact dermatitis is contact dermatitis. The rash pretty much looks the same no matter what the causative agent is. Poison ivy/oak/sumac cause a distinctive rash, but again, it could be any of those three that cause it.

06-06-2008, 09:11 AM
Here in Michigan it's hard to find any garden that poison ivy isn't creeping into. I start breaking out every spring straight into fall and haven't a clue what I've touched. Maybe my shoes?

There's also and interesting plant they call Indian Itch Weed that will tear your bare legs up like little razors. I heard a story about someone planting it as a private joke under their windows after someone had broken into their house.

06-08-2008, 10:58 AM
Many species of the Opuntia genus (prickly pears, chollas, and relatives) have spines with backward-directed barbs along the shafts, which means once in the skin, they will work their way in farther and be very difficult to get out. Also, one may be able to tell the species from the spine morphology. Each embedded spine creates a red, irritated lesion (experience), and even if pulled, it frequently leaves its tip as an irritating souvenir. Some species grow in areas of the U.S. one wouldn't expect--there are prickly pears growing in my area of coastal Carolina, a huge cluster right outside one of the Bojangles fast food restaurants near the university.

Tsu Dho Nimh
06-09-2008, 01:45 AM


You have to answer that before you can get any answers.

Claudia Gray
06-09-2008, 03:27 AM
I would just like to report that I misread the title of this thread as "rash-causing pants."