Hello everyone! My name is Caroline Mifsud and I am a student in PHR 7588: Toxic Substances. For my 4 topics, I chose to study Bacillus thuringiensis, arsenic, toluene, and poison ivy. I chose these four particular topics because not only were they specifically interesting to me, but they are all clinically relevant.
In the Bacillus thuringiensis blog, you’ll learn about the role that it plays as a pesticide. Interestingly, it is pretty safe to use in terms of toxicity. You’ll learn about the mechanism of action and how it works as an insecticide.
In the arsenic blog, you’ll learn about the differences between the three types of arsenic compounds: organic, inorganic, and arsine gas. In addition, you’ll discover the variety of places that arsenic can be found. Did you know it’s commonly found in rice and even drinking water? Later, you’ll read about a research study involving rats that suggests arsenic might be considered an essential metal.
In the toluene blog, you’ll explore the many ways that one could be exposed to toluene – and why you should avoid it! There is even some genetic differences in some people who have been exposed to toluene.
Finally, you’ll learn all about poison ivy, the plant that makes us all itchy. Did you know that over 85 percent of people are allergic to this pesky plant? You’ll get to see what a rash from poison ivy looks like, as well as learn about the different remedies to use if you do come into contact with it.
Thanks for taking the time to read my blog – I hope you enjoy!
Poison ivy, also known as Toxicodendron radicans, is a poisonous plant that characteristically has three leaves – as the saying goes “leaves of three, let it be.”
The causative agent in poison ivy, urushiol, is absorbed through the skin. From there, an allergic reaction ensues, and the immune system becomes activated. The rash is usually self-limiting, and the rash will eventually clear up, often without treatment.
The causative agent of poison ivy dermatitis is a substance found on the surface of the leaves called urushiol. After coming into contact with this substance, an allergic skin reaction typically ensues. (American Skin Association, American Osteopathic College of Dermatology).
The immune system produces a protein called interleukin 33 (IL-33), which is what triggers the itching associated with poison ivy dermatitis. In addition to causing inflammation, this protein is also capable of acting on nerves. (Researchers Identify Protein That Triggers Poison Ivy Itch).
Historically, it was thought that poison ivy could be used for medical purposes and healing.
André-Ignace-Joseph Dufresnoy, a physician in the 1700’s, was very interested in the effects of poison ivy and attempted to create medicines from poison ivy to heal skin wounds and even cure paralysis. He made a distilled extract using poison ivy and prescribed it to patients to attempt to “heal them.” He claimed to have positive results, but poison ivy is not used for these purposes today.
A Japanese chemist named Rikou Majima (pictured below) was the first to identify the causative agent in poison ivy as urushiol.
Here is a picture of Rikou Majima with his students.
In most cases, the rash is self-limiting and will heal on its own within two to three weeks. Thus, treatment is not usually required. However, some treatments exist:
over the counter corticosteroid cream
calamine lotion
oatmeal baths
oral antihistamines (diphenhydramine)
soak in a cold water bath
apply a cool compress to the affected area
in some cases, your doctor may prescribe a steroid such as prednisone
Oatmeal baths can be helpful to get rid of itchiness.
Disclaimer: I do not own any of these images or videos. They have been cited with their appropriate link.
References
1. Poison ivy dermatitis—American Osteopathic College of Dermatology (AOCD). https://www.aocd.org/page/PoisonIvyDermatiti. Accessed July 21, 2019.
2. Poison ivy, sumac and oak | American Skin Association. http://www.americanskin.org/resource/poisonivy.php. Accessed July 21, 2019.
3. Poison ivy rash—Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/poison-ivy/symptoms-causes/syc-20376485. Accessed July 21, 2019.
4. Poison ivy rash—Diagnosis and treatment—Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/poison-ivy/diagnosis-treatment/drc-20376490. Accessed July 21, 2019.
5. No ill nature: The surprising history and science of poison ivy and its relatives. Science History Institute. https://www.sciencehistory.org/distillations/no-ill-nature-the-surprising-history-and-science-of-poison-ivy-and-its-relatives. Published June 2, 2013. Accessed July 21, 2019.
6. Researchers identify protein that triggers poison ivy itch. National Institute of Environmental Health Sciences. https://www.niehs.nih.gov/research/supported/sep/2017/protein-poison-ivy-itch/index.cfm. Accessed July 21, 2019.
7. U.S. Food and Drug Administration. 4 Tips to Outsmarting Poisonous Plants. https://www.youtube.com/watch?v=CEBpYdgBALg&feature=youtu.be. Accessed July 21, 2019.
8. Centers for Disease Control and Prevention (CDC). How Poison Ivy Works. https://www.youtube.com/watch?v=dgwQ1DHepOw&feature=youtu.be. Accessed July 21, 2019.
9. Mayo Clinic. Mayo Clinic Minute: How to Treat Poison Ivy Rash. https://www.youtube.com/watch?v=G5mBkVdsoEE&feature=youtu.be. Accessed July 21, 2019.
