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Davis Square Family Practice
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Deborah Bershel, MD
Michelle Clark, NP
Carmen Phillips, NP
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Barbara Kaplan, LICSW
Christopher Mulvey, NP
Poison Ivy, Oak & Sumac:
A Rash of Information About Identification, Treatment & Prevention
What is it?
Poison ivy, oak and sumac belong to a family of plants that produce one of the most common allergic reactions in the United States. Experts estimate that up to 70 percent of the population is allergic to urushiol (you-roo-shee-ol), the oil found in the sap of these plants. The reaction, known as "urushiol-induced allergic contact dermatitis, " occurs when urushiol attaches itself to the skin after a person's direct or indirect exposure to the oil. Symptoms like rashes, oozing blisters, itching and swelling are the body's way of telling you that you are having an allergic reaction.
An example of a poison ivy allergic reaction.Wiping contaminated hands
on the neck produced the swollen, streaky appearance
An example of an allergic reaction to urushiol. Direct contact produced redness, swelling, blistering and rash.
What does it look like?
Poison Ivy, the most common of the three plants, is characterized by three or five serrated- edge, pointed leaflets. These leaves assume bright colors in the fall, turning yellow then red. assume bright colors in the fall, turning yellow then red.
Poison Oak has three oak-like leaves and grows as a low shrub in the eastern U .S. and as both low and high shrubs in the western U.S., where it is most prevalent. Poison oak produces whitish flowers from August to November that dry but may remain on the plant for many months.
Poison Sumac has seven to 13 staggered leaflets with one on the tip of the plant. Mainly found in the eastern U.S., poison sumac grows in peat bogs and swamps as a shrub or a small tree. The large allergen-containing fruit is red and grows between the leaf and the branch.
Poison Ivy, Oak & Sumac
Questions & Answer
Q: How do these plants cause allergic reactions?
A: Urushiol, the allergen found in these plants, attaches to the skin within five minutes to two hours after exposure. This event
triggers an allergic response, whereby the body's immune system attacks the skin containing the urushiol. Reactions result
from direct contact with broken leaves or stems of the plant; indirect contact by touching something that has urushiol on it (like
a family pet or garden tool); or through airborne exposure to burning plants.
Q: What are the signs and symptoms?
A: An allergic reaction to poison ivy (oak or sumac) is quite intense and far more common than any other cause of an allergic skin
reaction. Signs and symptoms include redness, swelling, warmth, blistering, tenderness and of course, itching.
Q: What are the treatment options?
A: Over-the-counter remedies like calamine lotion or hydrocortisone may alleviate the itch. Your physician also may prescribe
steroids for more severe cases to reduce inflammation and stop itching. However, side effects of excessive use may include
thinning of the skin, acne and discoloration. Oral steroids also carry health risks, especially for young children.
Zanfel™ Poison Ivy Wash provides a valuable alternative to drug therapies for mild to moderate cases. Sold in the First Aid
section of pharmacies. Zanfel is clinically shown to remove urushiol after breakout and relieve itching within seconds of use.
Medical experts caution against the use of topical creams containing anesthetics (benzocaine) or antihistamines
(diphenhydramine). because these agents are known sensitizers that can actually worsen the rash through the body's allergic
response to these drugs. Further, there is doubt of their effectiveness.
What to do if you 've been exposed to poison ivy , oak or sumac :
I) Cleanse: Immediately cleanse the area with plain soap and water, paying special attention to the palms of your hands. Since
this outer layer of skin is thicker, urushiol does not penetrate the area and can be carried on the palms for hours. Urushiol will
bind to the skin within five minutes to two hours after exposure. After binding, plain soap and water are no longer effective at
2) Decontaminate: Remove and wash all clothing, shoes and shoelaces that may have come in contact with the oil.
3) Relieve: If signs or symptoms appear, use Zanfel, the only product clinically shown to remove urushiol from the skin after
breakout and relieve itching. Removing urushiol is the most important step in eliminating the reaction. Other common remedies,
such as calamine lotion, may produce mild and temporary relief of the itch but will not remove the oil.
4) Don't scratch! Scratching may cause infection because it allows bacteria from dirt on the hands to enter the skin. Excessive
scratching may also cause scarring.
5) See your family physician: Be sure to consult your family physician if symptoms worsen and/or the rash spreads to the mouth,
eyes or genitals. Severe reactions may require further treatment.
Itching for more information?
|Poison ivy rash is contagious.
||Since poison ivy rash is an allergic reaction to urushiol (the toxin found in poison ivy, oak and sumac plants). the only way to contract poison ivy is through direct contact with the plant; indirect contact by touching something that has urushiol on it (like a family pet or garden tool); or through airborne exposure to burning plants.
|Scratching poison ivy blisters will spread the rash
||The fluid in the blisters will not spread the rash. After the first five minutes to two hours following exposure, neither scratching nor skin-to-skin contact can spread the reaction.
However, excessive scratching may cause infection because it allows bacteria from dirt on the hands to enter the skin.
|Dead poison ivy plants are
no longer toxic
|Urushiol stays active on any surface, including dead plants, for up to five years in wet climates and up to nine years in dry climates.
|Once allergic, always allergic
to poison ivy.
|A person's sensitivity changes over time, even from season to season. Sensitivity to poison ivy tends to decline with age, as the body's immune system slows down.
How to prevent a scratchy situation
1) Know what to look for and educate your family.
Prevention is the best form of protection from poison ivy, oak and sumac reactions. Before you head outside, make sure your
family knows how to identify these plants so they can avoid them.
2) Wear protective clothing.
Shielding clothing, including long pants, long- sleeved shirts, hats and gloves, can help protect you from exposure.
3) Wash outdoor items frequently.
Be sure to wash all clothing, shoes, tools or pets that may have been exposed.
4) Do not burn any suspicious plants.
Burning the problematic plant and inhaling its smoke can cause a systemic reaction, which can be deadly. Also, do not burn
items of clothing or rags that may have been exposed.
5) Stop the symptoms before they start.
If you know you've been exposed to poison ivy, cleanse the area immediately with plain soap and water to remove urushiol
before it has a chance to bind to the skin.