UrushiolUrushiol

Mechanisms of Mechanisms of TransmissionTransmission

Urushiol can be TransmittedUrushiol can be Transmitted

By contact with the By contact with the plants that contain it.plants that contain it.

By contact with By contact with inanimate objects which inanimate objects which have come in contact have come in contact with it.with it.

By contact with other By contact with other living things that have living things that have come in contact with it.come in contact with it.

Direct Contact with the Skin Direct Contact with the Skin

The easiest, most The easiest, most common way to get common way to get dermatitis from urushiol dermatitis from urushiol is to physically contact is to physically contact any part of the plants any part of the plants that contain it.that contain it.

Often this happens Often this happens without notice – without notice – symptoms may not symptoms may not show up for several show up for several days, if at all.days, if at all.

Poison IvyPoison Ivy

Poison OakPoison Oak

Poison SumacPoison Sumac

Contact with Contaminated ObjectsContact with Contaminated Objects

These can include These can include clothing or shoes that clothing or shoes that have contacted urushiol.have contacted urushiol.

A guy was wearing A guy was wearing these pants when he these pants when he encountered poison oak. encountered poison oak. His legs were covered in His legs were covered in blisters.blisters.

Urushiol can stay on Urushiol can stay on unwashed clothes for up unwashed clothes for up to a year.to a year.

Contact with Contaminated ObjectsContact with Contaminated Objects

Dead dry leaves still Dead dry leaves still contain active urushiol contain active urushiol for some time.for some time.

The same is true for The same is true for gardening tools.gardening tools.

Contact with Contaminated AnimalsContact with Contaminated Animals

Animals can get Animals can get urushiol on their fur and urushiol on their fur and have no reaction, but have no reaction, but can transfer it to can transfer it to humans.humans.

Once skin exposed to Once skin exposed to urushiol has been urushiol has been thoroughly washed, thoroughly washed, human-to-human human-to-human transmission is nearly transmission is nearly impossible.impossible.

How does it work?How does it work?

Chemically, urushiol is harmless to humans.Chemically, urushiol is harmless to humans. However, when contacted, it bonds to deep However, when contacted, it bonds to deep

skin proteins. skin proteins. This initiates a T-cell mediated immune This initiates a T-cell mediated immune

response towards the urushiol derivatives response towards the urushiol derivatives which are bound up in the skin proteins. which are bound up in the skin proteins.

The result is an allergic reaction characterized The result is an allergic reaction characterized by redness, swelling, and blisters. by redness, swelling, and blisters.

What happens What happens

Urushiol causes an Urushiol causes an allergic reaction (Rhus allergic reaction (Rhus dermatitis) in about dermatitis) in about 85% of people exposed 85% of people exposed to it.to it.

This percentage This percentage decreases with age.decreases with age.

Breathing burning Breathing burning urushiol can be urushiol can be extremely serious.extremely serious.

In severe cases there is a In severe cases there is a risk of anaphylactic risk of anaphylactic shock.shock.

As with many allergies, As with many allergies, reactions become more reactions become more pronounced with pronounced with repeated exposures.repeated exposures.

Once a rash develops, it Once a rash develops, it can linger for up to a can linger for up to a month.month.

Examples of ReactionsExamples of Reactions

RecurrenceRecurrence

Strangely, a rash may Strangely, a rash may appear months – even appear months – even years – later, despite years – later, despite there being no further there being no further exposures.exposures.

ReferencesReferences Poison Sumac Poison Sumac http://www.poison-sumac.orghttp://www.poison-sumac.org// Aetna Intellihealth Aetna Intellihealth

http://www.intelihealth.com/IH/ihtIH/WSIHW000/79http://www.intelihealth.com/IH/ihtIH/WSIHW000/7945/7991/442902.html45/7991/442902.html

The University of Iowa The University of Iowa http://www.uihealthcare.com/topics/medicaldepartmehttp://www.uihealthcare.com/topics/medicaldepartments/dermatology/poisonivy/index.htmlnts/dermatology/poisonivy/index.html

Poison Ivy, Oak and Sumac Information Center Poison Ivy, Oak and Sumac Information Center http://poisonivy.aesir.com/view/comments.html?funchttp://poisonivy.aesir.com/view/comments.html?func=showMessage&mid=100590&wid=279=showMessage&mid=100590&wid=279

Wikipedia http://en.wikipedia.org/wiki/Urushiol-Wikipedia http://en.wikipedia.org/wiki/Urushiol-induced_contact_dermatitisinduced_contact_dermatitis