Transcript The Curse of Toxicodendron

The Curse
of
Toxicodendron
Bryan E. Bledsoe, DO, FACEP
Midlothian, Texas
Toxicodendron
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“Leaves of three,
let them be;
berries white, run
in fright.”
Toxicodendron
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Name comes from the Greek:
– Toxikos (poisonous)
– Dendron (tree)
Toxicodendron
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Poison ivy was
one of the
earliest plants
noted by the first
colonists.
Toxicodendron
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In 1609, Captain
John Smith is
credited with
naming the plant
“poison ivy”
because he thought
it resembled English
ivy or Boston ivy.
He also observed
that the plant
"caused itchynge,
and lastly, blisters."
Toxicodendron
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Kingdom: Plantae (Plants)
Division: Magnoliophyta (flowering plants)
Class: Magnoliopsida, (Dicotyledons)
Subclass: Rosidae (Roses)
Order: Sapindales
Family: Anacardiaceae (cashews, mangos,
and pistachios)
Genus: Toxicodendron (poison ivies, oaks,
and sumacs)
Toxicodendron
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Relatives include:
– Cashews
– Mangos
– Pistachios
Toxicodendron
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Virtually every part
of the United
States, except
desert regions, is
home to members
of the
Toxicodendron
family.
Toxicodendron
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Highly variable
species with
multiple sub-types
and regional
variance.
Toxicodendron
Toxicodendron
Toxicodendron
Spring
Toxicodendron
Summer
Toxicodendron
Fall
Toxicodendron
Winter
Toxicodendron
All
Seasons
Toxicodendron
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Species found in North America:
– Poison ivy (T. radicans)
– Rydberg’s poison ivy (T. rydbergii)
– Western poison oak (T. diversilobum)
– Eastern poison oak (T. toxicarium)
– Poison sumac (T. vernix)
Eastern Poison Ivy
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Toxicodendron
radicans.
Often called “climbing
poison ivy.”
Found throughout the
US and Canada.
Typically a climbing
vine, although it can be
found as an upright
shrub.
Blooms in June
Eastern Poison Ivy
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6 sub-species:
– T. radicans divaricatum
– T. radicans eximium
– T. radicans negundo
– T. radicans pubens
– T. radicans radicans
– T. radicans verrucosum
T. Radicans (all)
T. radicans divaricatum
T. radicans divaricatum
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Fairly rare species.
Found in
southeastern
corner of Arizona
and extends into
Mexico.
Also called “Baja
California Poison
Ivy.”
T. radicans eximium
T. radicans eximium
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Fairly rare species
Occurs in
southwest Texas
and Mexico
T. radicans negundo
T. radicans negundo
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Fairly common
species.
Found in south
Ontario, great lakes
states, central and
mid-western states.
T. radicans pubens
T. radicans pubens
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Fairly common
species.
Found in south
central US from
lower Mississippi
valley to east
Texas.
T. radicans radicans
T. radicans radicans
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Moderately
common species
Found in eastern
and southeastern
US, Bermuda, the
Bahamas, and
Nova Scotia.
T. radicans verrucosum
T. radicans verrucosum
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Moderately
common species.
Found in Texas,
Oklahoma, and
southwestern
Missouri.
Western Poison Ivy
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Toxicodendron
rydbergii
Also called:
– Non-climbing poison ivy
– Rydberg’s poison ivy
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Grows as a bush up to
3 feet high.
Most northerly of
Toxicodendron
T. Rydbergii
Western Poison Oak
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Toxicdendron
diversilobum
Grows as a thick
bush or a climbing
vine.
T. diversilobum
Western Poison Oak
Eastern Poison Oak
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Toxicodendron
toxicarium
Grows in sandy soil
and areas
devastated by fire.
T. toxicarium
Poison Sumac
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Toxicodendron
vernix
Least encountered
member of
Toxicodendrom
family
Water-loving plant
found in swamps
and bogs.
T. vernix
Poison Sumac
Toxicodendron
Major problem in the United States
and Canada.
 Estimated that more than 50% of
workmen’s compensation cases in
California are due to contact dermatitis
from Western Poison Oak.
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Pathophysiology
Pathophysiology
Poison ivy is not an “allergy” as
interpreted by most people.
 It is a cell-mediated reaction that does
not involve antibodies.
 Classified as Type IV Hypersensitivity
reaction (Delayed Hypersensitivity)
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Pathphysiology
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Initial Exposure:
– Patient comes into contact with the
allergen.
– Allergens are harmless to most people.
– Some are born with or later develop a
hypersensitivity to the allergen in
question.
Toxicodendron
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All species of
Toxicodendron
contain substances
in their sap called
urushiols (also
called catechols).
Group of oils
secreted onto the
plant’s surface.
Pathophysiology
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Urushiol resin remains stable for years,
even in dead or dried plants, and is equally
hazardous in the winter as in the summer.
The resin can be carried by smoke if the
plant is burned and infect the lungs.
Ingesting any part of the plant can cause a
reaction in the oral cavity and
gastrointestinal tract.
Pathophysiology
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Estimated that 50-70% of the U.S.
population is sensitized to urushiol, and
would acquire the rash on casual contact.
Prolonged or repeated exposure may
induce an allergic response to urushiol.
The reaction ranges from mild to severe,
and sensitivity can develop later in life.
Pathophysiology
When urushiols are exposed to the air,
they quickly oxidize and turn a dark
brown.
 If a leaf is placed between two white
sheets of paper and the leaf is
crushed, the wet spots will turn brown
in a matter of minutes.
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Pathophysiology
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When sensitized, exposure results in 3
stages of response:
– Redness
– Rash and Blisters
– Rupture of Blisters
Pathophysiology
1. A day or two after contact the
infected area begins to itch and
becomes red from the dilation of blood
vessels. Swelling (lymph leaking from
the blood vessels) also occurs.
Pathophysiology
2. Two days later, blisters filled with
clear fluid appear.
Pathophysiology
3. Lastly large blisters burst and begin
to ooze for about four days.
Toxicodendron
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If you are sensitized to poison ivy, you are
also sensitized to poison oak and poison
sumac, and may be sensitized to:
– cashew nut shell oil
– mango fruit peels
– Japanese lacquer.
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A person is not sensitized to poison ivy the
first time they touch it, but can become
sensitized as the skin processes the resin.
Toxicodendron
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Treatment:
– Prevention
 Limiting
Exposure
 Barrier Creams and Lotions
 Plant Removal
– Localized Treatment
– Generalized Treatment
– Massive Exposures
Treatment
Prevention
is the Best
Treatment!
Treatment
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Limit Exposure:
– Wear long sleeves and pants.
– Wear gloves when working in areas
where plants are common.
– Wear a mask when mowing in areas
where plants are common.
Treatment
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Limit Exposure:
– Pets can get resin on them and transfer it
to you.
– Resin will remain in clothing unless you
wash it in hot water with a good soap.
Treatment
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Limit Exposure:
– If you are exposed, rinse affected area
with cold water.
– Hot water will open up the pores and
increase exposure.
– Clean under fingernails.
– Use strong soap
– DO NOT RETURN TO PLANT AREA
AFTER USING SOAP.
Treatment
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Limit Exposure:
– Consider the use of
poison ivy/oak
solvents to break
down the resin.
Treatment
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Barrier Creams and Lotions
– For the most part, barrier creams and
lotions are ineffective because of
sweating and movement.
– Many brands are available on the market
without a prescription.
Treatment
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Barrier Creams and Lotions:
Treatment
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Plant Removal:
– Herbicides
Treatment
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Plant Removal:
– Physical Removal (best performed in
Winter months).
1.
2.
3.
4.
5.
Cover yourself with clothing, gloves, and
mask (Ivy Block if you want).
Loosen the soil by moistening with water.
Remove and carefully bag plants.
DO NOT BURN PLANTS!
Shower immediately to remove any possible
resin.
Treatment
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Plant Removal:
– Physical Removal
Treatment
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Localized Treatment:
1. Minimize exposure with soaps or
solvents.
2. Localized analgesic creams or
ointments.
3. Antihistamines for itching.
4. OTC steroid creams (Cort-Aid)
5. Prescription steroid creams (Diprolene)
Treatment
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Localized Treatment:
Treatment
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Localized Treatment:
Treatment
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Localized Treatment:
Treatment
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Localized Treatment:
Treatment
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Generalized Treatment:
– If significant body area exposed, then
localized treatment will be ineffective and
expensive.
– Genital exposure can be quite
bothersome.
– Use local remedies as needed.
– Definitive treatment is high-dose
corticosteroids.
Treatment
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Generalized Treatment:
– I typically prescribe the following steroid
regimen:
 Prednisone
60 mg a day for 3 days,
 Then 40 mg a day for 3 days,
 Then 20 mg a day for 3 days, then stop.
– Hydroxyzine 50 mg QID prn itching.
Treatment
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Massive Exposure:
– High-dose steroids
– Analgesics
– Hospitalization
– Potent antihistamines
– Pity
Treatment
Myths
1.
2.
3.
4.
You can get poison ivy from the fluid
in the blisters.
There is a shot that prevents poison
ivy.
Injected steroids are better than oral
steroids.
If I am “allergic” to poison ivy, then
my kids must be “allergic.”
Myths
5.
6.
7.
8.
Medrol “Dose Packs” are satisfactory
treatment for generalized rashes.
It is safe to burn the plants.
Removing the plants in Winter is safe
as the resin is gone.
Homeopathic remedies will treat or
prevent poison ivy.
Myths
9.
10.
I can get the rash from somebody who
has it.
Benadryl cream or spray is an
effective treatment.
Summary
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“Leaves of three,
let them be;
berries white, run
in fright.”