Editing Toxicodendron radicans (section)

== Toxicity ==
[[File:How Poison Ivy Works.webm|thumb|upright=1.3|A video describing the effects of poison ivy on the body]]
[[File:Urushiol induced contact dermatitis.jpg|thumb|upright=1.3|[[Blister]]s from contact with poison ivy]]
{{Main|Urushiol-induced contact dermatitis}}
Urushiol-induced contact dermatitis is the [[allergy|allergic reaction]] caused by poison ivy. In extreme cases, a reaction can progress to [[anaphylaxis]]. Around 15 to 25 percent of people have no allergic reaction to urushiol, but most people have a greater reaction with repeated or more concentrated exposure.<ref name="hsw">{{cite web|url=http://science.howstuffworks.com/poison-ivy.htm|title=How Poison Ivy Works|work=HowStuffWorks|date=23 September 2005}}</ref><ref>{{cite web|url=http://mic-ro.com/plants/|title=Contact-Poisonous Plants of the World|author=Rohde, Michael|work=mic-ro.com|access-date=2004-06-12|archive-date=2010-07-02|archive-url=https://web.archive.org/web/20100702160140/http://mic-ro.com/plants/|url-status=dead}}</ref> Typically, the rash from the urushiol oil lasts about five to twelve days, but in extreme cases, it can last a month or more.<ref>{{cite web|url=https://www.gemplers.com/tech/faq-poison-ivy.htm|title=Poison Ivy, Poison Oak and Poison Sumac FAQs}}</ref>

Over 350,000 people are affected by urushiol annually in the United States.<ref>{{cite news|last=Chaker|first=Anne Marie|title=Least-Welcome Sign of Summer|newspaper=[[The Wall Street Journal]]|date=June 22, 2010|author2=Athavaley, Anjali|page=D1}}</ref>

The pentadecyl [[catechols]] of the [[oleoresin]] within the sap of poison ivy and related plants causes the allergic reaction; the plants produce a mixture of pentadecylcatechols, which collectively is called urushiol. After injury, the sap leaks to the surface of the plant where the urushiol becomes a blackish [[lacquer]] after contact with oxygen.<ref name="Barceloux2008">{{cite book |author=Barceloux, Donald G. |url=https://books.google.com/books?id=CpqzhHc072AC&pg=PA681 |title=Medical Toxicology of Natural Substances: Foods, Fungi, Medicinal Herbs, Plants, and Venomous Animals |publisher=John Wiley and Sons |year=2008 |isbn=978-0-471-72761-3 |pages=681–}}</ref><ref name="RietschelFowler2008">{{cite book|author1=Rietschel, Robert L. |author2=Fowler, Joseph F. |author3=Fisher, Alexander A. |title=Fisher's contact dermatitis|url=https://books.google.com/books?id=dQBAzfyCeQ8C&pg=PA408|year=2008|publisher=PMPH-USA|isbn=978-1-55009-378-0|pages=408–}}</ref>

Urushiol binds to the skin on contact, where it causes severe itching that develops into reddish inflammation or uncoloured bumps, and then [[blister]]ing. These [[lesions]] may be treated with [[Calamine]] lotion, [[Burow's solution]] compresses, dedicated commercial poison ivy itch creams, or baths to relieve discomfort,<ref>Wilson, W. H. & Lowdermilk, P. (2006). Maternal Child Nursing Care (3rd edition). St. Louis: Mosby Elsevier.</ref> though recent studies have shown some traditional medicines to be ineffective.<ref>{{cite web |url=http://www.iht.com/articles/1992/09/09/topi.php |title=American Topics. An Outdated Notion, That Calamine Lotion |access-date=2007-07-19 |archive-url = https://web.archive.org/web/20070619004539/http://www.iht.com/articles/1992/09/09/topi.php <!-- Bot retrieved archive --> |archive-date = 2007-06-19}}</ref><ref>{{cite journal | last1 = Appel | first1 = L.M. Ohmart | last2 = Sterner | first2 = R.F. | year = 1956 | title = Zinc oxide: A new, pink, refractive microform crystal | journal = AMA Arch Dermatol | volume = 73 | issue = 4| pages = 316–324 | doi = 10.1001/archderm.1956.01550040012003 | pmid = 13301048 }}</ref> [[Over-the-counter]] products to ease itching—or simply oatmeal baths and [[baking soda]]—are now recommended by [[dermatologists]] for the treatment of poison ivy.<ref>{{cite web |url=http://www.aad.org/public/publications/pamphlets/skin_poison.html |title=American Academy of Dermatology – Poison Ivy, Oak & Sumac |url-status=dead |archive-url=https://web.archive.org/web/20090605182107/http://www.aad.org/public/publications/pamphlets/skin_poison.html |archive-date=2009-06-05 }}</ref>

A plant-based remedy cited to counter urushiol-induced contact dermatitis is [[Impatiens|jewelweed]], though jewelweed extracts had no positive effect in clinical studies.<ref>{{cite journal | last1 = Long | first1 = D. | last2 = Ballentine | first2 = N. H. | last3 = Marks | first3 = J. G. | year = 1997 | title = Treatment of poison ivy/oak allergic contact dermatitis with an extract of jewelweed. | journal = Am. J. Contact. Dermat | volume = 8 | issue = 3| pages = 150–3 | pmid = 9249283 | doi=10.1097/01206501-199709000-00005}}</ref><ref>{{cite journal | last1 = Gibson | first1 = MR | last2 = Maher | first2 = FT | title = Activity of jewelweed and its enzymes in the treatment of Rhus dermatitis. | journal = Journal of the American Pharmaceutical Association | volume = 39 | issue = 5 | pages = 294–6 | year = 1950 | pmid = 15421925 | doi=10.1002/jps.3030390516}}</ref><ref>{{cite journal | last1 = Guin | first1 = J. D. | last2 = Reynolds | first2 = R. | year = 1980 | title = Jewelweed treatment of poison ivy dermatitis. | journal = Contact Dermatitis | volume = 6 | issue = 4| pages = 287–8 | doi = 10.1111/j.1600-0536.1980.tb04935.x | pmid = 6447037 | s2cid = 46551170 }}</ref><ref>{{cite journal | last1 = Zink | first1 = B. J. | last2 = Otten | first2 = E. J. | last3 = Rosenthal | first3 = M. | last4 = Singal | first4 = B. | year = 1991 | title = The effect of jewel weed in preventing poison ivy dermatitis| journal = Journal of Wilderness Medicine | volume = 2 | issue = 3 | pages = 178–182 | doi = 10.1580/0953-9859-2.3.178 | s2cid = 57162394 }}</ref> Others argue that prevention of lesions is easy if one practices effective washing, using plain soap, scrubbing with a washcloth, and rinsing three times within 2–8 hours of exposure.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/4oyoDRHpQK0 Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20140625003135/https://www.youtube.com/watch?v=4oyoDRHpQK0 Wayback Machine]{{cbignore}}: {{Cite web|author=Extreme Deer Habitat|title=How to never have a serious poison ivy rash again|website=[[YouTube]]|date=2014-06-22|url=https://www.youtube.com/watch?v=4oyoDRHpQK0|access-date=2016-07-26}}{{cbignore}}</ref>

The oozing fluids released by scratching blisters do not spread the poison. The fluid in the blisters is produced by the body and it is not urushiol itself.<ref name=faq/> The appearance of a spreading rash indicates that some areas received more of the poison and reacted sooner than other areas or that contamination is still occurring from contact with objects to which the original poison was spread. Those affected can unknowingly spread the urushiol inside the house, on phones, doorknobs, couches, counters, desks, and so on, thus in fact repeatedly coming into contact with poison ivy and extending the length of time of the rash. If this has happened, wipe down the surfaces with bleach or a commercial urushiol removal agent. The blisters and oozing result from blood vessels that develop gaps and leak fluid through the skin; if the skin is cooled, the vessels constrict and leak less.<ref name="Prevention2010">{{cite book|author=((Editors of Prevention))|title=The Doctors Book of Home Remedies: Quick Fixes, Clever Techniques, and Uncommon Cures to Get You Feeling Better Fast|url=https://books.google.com/books?id=ExFziuyaXWcC&pg=PA488|date= 2010|publisher=Rodale|isbn=978-1-60529-866-5|pages=488–}}</ref> If plant material with urushiol is burned and the smoke then inhaled, this rash will appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty.<ref name=faq/> If poison ivy is eaten, the mucous lining of the mouth and digestive tract can be damaged.<ref name="Lewis1998">{{cite book|author=Lewis, Robert Alan |title=Lewis' dictionary of toxicology|url=https://books.google.com/books?id=caTqdbD7j4AC&pg=PA901|year=1998|publisher=CRC Press|isbn=978-1-56670-223-2|pages=901–}}</ref> An urushiol rash usually develops within a week of exposure and can last 1–4 weeks, depending on severity and treatment. In rare cases, urushiol reactions may require hospitalization.<ref name=faq>{{cite web |url=http://www.poison-ivy.org/html/faq.htm |title=Facts about Poison Ivy: How long does the rash last?, What can you do once the itching starts?, How do you get poison ivy? |website=poison-ivy.org |date=25 February 2015 |access-date=21 July 2009 |archive-date=30 June 2010 |archive-url=https://web.archive.org/web/20100630183437/http://www.poison-ivy.org/html/faq.htm |url-status=dead }}</ref>

Urushiol oil can remain active for several years, so handling dead leaves or vines can cause a reaction. In addition, oil transferred from the plant to other objects (such as pet fur) can cause the rash if it comes into contact with the skin.<ref>{{cite web|url=http://www.aad.org/public/Publications/pamphlets/Poison_IvyOakSumac.htm|title=Poison Ivy, Oak & Sumac|work=aad.org|url-status=dead|archive-url=https://web.archive.org/web/20070708105008/http://www.aad.org/public/Publications/pamphlets/Poison_IvyOakSumac.htm|archive-date=2007-07-08}}</ref><ref name=faq/> Clothing, tools, and other objects that have been exposed to oil should be washed to prevent further reactions.<ref>{{cite web |title=Poison ivy - oak - sumac |url=https://medlineplus.gov/ency/article/002886.htm |website=MedlinePlus Medical Encyclopedia |publisher=[[A.D.A.M., Inc.]] |access-date=16 June 2019}}</ref>

People who are sensitive to urushiol can also experience a similar rash from [[mangoes]]. Mangoes are in the same family (Anacardiaceae) as poison ivy; the sap of the mango tree and skin of mangoes has a chemical compound similar to urushiol.<ref>{{cite journal|doi=10.1056/NEJM199807233390405|pmid=9673302|title=The Mango–Poison Ivy Connection|journal=New England Journal of Medicine|volume=339|issue=4|pages=235|year=1998|last1=Tucker|first1=Mark O.|last2=Swan|first2=Chad R.}}</ref> A related allergenic compound is present in the raw shells of [[cashew]]s.<ref name="Rosen">{{cite journal
 |last = Rosen |first = T. |author2=Fordice, D. B.
  |title = Cashew Nut Dermatitis |journal = Southern Medical Journal | volume = 87 | issue = 4
 |pages = 543–546 |date = April 1994|doi = 10.1097/00007611-199404000-00026| pmid = 8153790 }}</ref> Similar reactions have been reported occasionally from contact with the related Fragrant Sumac (''[[Rhus aromatica]]'') and [[Toxicodendron vernicifluum|Japanese lacquer tree]].{{citation needed|date=September 2021}} These other plants are also in the family Anacardiaceae.

=== Treatment ===
{{Main|Urushiol-induced contact dermatitis#Treatments}}

Immediate washing with soap and cold water or [[rubbing alcohol]] may help prevent a reaction.<ref>{{cite web|url=http://www.teclabsinc.com/blog/2012/8/2/common-misconceptions-about-treating-poison-ivy-or-oak-rash|title=Misconceptions About Treating Poison Ivy and Oak Rash|work=teclabsinc.com|url-status=dead|archive-url=https://web.archive.org/web/20140826160923/http://www.teclabsinc.com/blog/2012/8/2/common-misconceptions-about-treating-poison-ivy-or-oak-rash|archive-date=2014-08-26}}</ref> During a reaction, Calamine lotion or [[diphenhydramine]] may help mitigate symptoms. [[Corticosteroid]]s, either applied to the skin or taken by mouth, may be appropriate in extreme cases. An astringent containing aluminum acetate (such as [[Burow's solution]]) may also provide relief and soothe the uncomfortable symptoms of the rash.<ref>{{cite journal|last1=Gladman|first1=Aaron C.|title=Toxicodendron Dermatitis: Poison Ivy, Oak, and Sumac|journal=Wilderness & Environmental Medicine|date=June 2006|volume=17|issue=2|pages=120–128|doi=10.1580/PR31-05.1|pmid=16805148|doi-access=free}}</ref>