POISON IVY
Steering Clear of Poison Ivy
By Jane E. Brody : NY Times : June 16, 2014
I was once among those who claim, “I could walk through a field of poison ivy and not get it.” One day I learned otherwise: On a hike, I needed to relieve myself in the great outdoors and ended up with an impossibly itchy, blistering rash on a most delicate body part.
Too late I learned that you can develop an allergic reaction to poison ivy after previously uneventful exposures, which induce a sensitivity to the plant’s oily sap, urushiol. Once sensitized, your skin is likely to react to every subsequent exposure. Even people repeatedly exposed who appear to be immune may react to high concentrations of the toxin.
I also learned not to rely on the popular warning, “Leaves of three, let them be,” to alert me to the presence of Toxicodendron radicans, as the poison ivy plant is aptly called by botanists. It is not just the leaves that can provoke a reaction; the stems, roots, flowers and berries all contain urushiol.
Touching or brushing against any of these plant parts, even if they are dead, can cause a reaction. The sap is hardy and can cause a rash in the dead of winter, or even a year after contaminating clothing or shoes that are not thoroughly cleaned.
Urushiol shows up elsewhere, including in the skin of mangoes (and the leaves and bark of the mango tree), as I discovered when I ate a mango still in the rind and ended up with a blistering rash on my mouth. Cashew shells also have the toxin, which is why cashews are sold shelled and processed (either roasted or in the case of “raw” cashews, steamed) at a temperature high enough to destroy urushiol. Poison ivy is not the only problem plant one might encounter while hiking, camping or simply strolling in the countryside. T. radicans has two relatives, poison oak and poison sumac, that don’t always form the classic clusters but are equally toxic troublemakers.
Myths and misconceptions abound about these three plants and the reactions they can cause. Knowing the facts can help to spare you and your family considerable distress.
First, learn to recognize the plants in their various growth patterns. While poison ivy is most often encountered as a small ground plant, it also grows as a shrub and vine. The vines, which turn bright red in fall, were once used to adorn buildings in England.
Poison oak, which has compound leaves made up of three (or sometimes five) leaflets, usually grows as a shrub, but will form a vine in the Western states.
Poison sumac, which grows as a tall shrub or small tree, produces leaves with rows of paired leaflets and a single leaflet at the end. It likes a wet habitat, growing in peat bogs in the Northeast and Midwest and swamps in the Southeast.
Urushiol can penetrate cloth. Although long sleeves, pants and gloves can reduce the risk of exposure, they cannot guarantee protection. Even rubber gloves can be breached. If you must handle the plants or are likely to contact poison ivy when gardening, wear vinyl gloves.
You don’t have to touch the plant directly to react to urushiol. Gardening tools, sporting equipment, even a pet that has been in a patch of poison ivy — all can cause a reaction. My brother, who has been sensitive to urushiol since childhood, once developed the rash on his arm after retrieving a baseball that had rolled through poison ivy.
Before possible exposure, use an over-the-counter skin-care product containing bentoquatam (IvyBlock) to prevent or reduce absorption of urushiol. The combination of this barrier product and protective clothing is your best defense against an inadvertent encounter.
But there is no scientific evidence that jewelweed, feverfew, plantain or other herbal remedies prevent or cure a urushiol-induced rash.
Nor do you become immune to urushiol through repeated exposures to small amounts. Quite the opposite. There is no way to desensitize a person to urushiol as there is with pollen and peanut allergies. Eating mangoes or cashews will not work.
Contrary to popular belief, a poison ivy rash is not contagious. It cannot be spread by oozing blisters, or by scratching or touching the rash. Only direct contact with urushiol causes a reaction. (Scratching can result in an infection, however.)
The rash can appear on different parts of the body at various times. This may happen because the parts were exposed at different times, or because areas with thicker skin are less easily penetrated by the oil. The delicate skin of the genital and perianal areas, for example, is more easily breached than tougher skin on the hands.
Repeated tilling or mowing can eventually kill poison ivy plants, as can repeated applications of an herbicide like Roundup. The latter should be applied with serious caution and only on a warm, sunny day with little or no wind when the plants are actively growing.
If you are highly allergic, or wary of applying herbicides, clearing your property of the plants may be best left to a professional. While goats are said to have a hearty appetite for poison ivy plants, they may eat everything else in the yard, too.
Never try to burn a poison plant. Burning releases the toxin, which may land on skin or, worse, be inhaled and cause a serious internal reaction.
Should you contact a urushiol-containing plant, the American Academy of Dermatology recommends washing your skin immediately. Lukewarm, soapy water is best, but even plain water can limit exposure to the sap. Take care in removing contaminated clothing, and wash it separately as soon as possible.
You can relieve a rash by applying cool compresses with an astringent like Burow’s solution, soaking the affected area in colloidal oatmeal, or using calamine lotion; all are sold over the counter. Do not apply products containing a topical antihistamine, like Benadryl, which can cause a sensitivity reaction that makes matters worse.
Severe reactions may require medically prescribed treatment with an oral corticosteroid like prednisone.
By Jane E. Brody : NY Times : June 16, 2014
I was once among those who claim, “I could walk through a field of poison ivy and not get it.” One day I learned otherwise: On a hike, I needed to relieve myself in the great outdoors and ended up with an impossibly itchy, blistering rash on a most delicate body part.
Too late I learned that you can develop an allergic reaction to poison ivy after previously uneventful exposures, which induce a sensitivity to the plant’s oily sap, urushiol. Once sensitized, your skin is likely to react to every subsequent exposure. Even people repeatedly exposed who appear to be immune may react to high concentrations of the toxin.
I also learned not to rely on the popular warning, “Leaves of three, let them be,” to alert me to the presence of Toxicodendron radicans, as the poison ivy plant is aptly called by botanists. It is not just the leaves that can provoke a reaction; the stems, roots, flowers and berries all contain urushiol.
Touching or brushing against any of these plant parts, even if they are dead, can cause a reaction. The sap is hardy and can cause a rash in the dead of winter, or even a year after contaminating clothing or shoes that are not thoroughly cleaned.
Urushiol shows up elsewhere, including in the skin of mangoes (and the leaves and bark of the mango tree), as I discovered when I ate a mango still in the rind and ended up with a blistering rash on my mouth. Cashew shells also have the toxin, which is why cashews are sold shelled and processed (either roasted or in the case of “raw” cashews, steamed) at a temperature high enough to destroy urushiol. Poison ivy is not the only problem plant one might encounter while hiking, camping or simply strolling in the countryside. T. radicans has two relatives, poison oak and poison sumac, that don’t always form the classic clusters but are equally toxic troublemakers.
Myths and misconceptions abound about these three plants and the reactions they can cause. Knowing the facts can help to spare you and your family considerable distress.
First, learn to recognize the plants in their various growth patterns. While poison ivy is most often encountered as a small ground plant, it also grows as a shrub and vine. The vines, which turn bright red in fall, were once used to adorn buildings in England.
Poison oak, which has compound leaves made up of three (or sometimes five) leaflets, usually grows as a shrub, but will form a vine in the Western states.
Poison sumac, which grows as a tall shrub or small tree, produces leaves with rows of paired leaflets and a single leaflet at the end. It likes a wet habitat, growing in peat bogs in the Northeast and Midwest and swamps in the Southeast.
Urushiol can penetrate cloth. Although long sleeves, pants and gloves can reduce the risk of exposure, they cannot guarantee protection. Even rubber gloves can be breached. If you must handle the plants or are likely to contact poison ivy when gardening, wear vinyl gloves.
You don’t have to touch the plant directly to react to urushiol. Gardening tools, sporting equipment, even a pet that has been in a patch of poison ivy — all can cause a reaction. My brother, who has been sensitive to urushiol since childhood, once developed the rash on his arm after retrieving a baseball that had rolled through poison ivy.
Before possible exposure, use an over-the-counter skin-care product containing bentoquatam (IvyBlock) to prevent or reduce absorption of urushiol. The combination of this barrier product and protective clothing is your best defense against an inadvertent encounter.
But there is no scientific evidence that jewelweed, feverfew, plantain or other herbal remedies prevent or cure a urushiol-induced rash.
Nor do you become immune to urushiol through repeated exposures to small amounts. Quite the opposite. There is no way to desensitize a person to urushiol as there is with pollen and peanut allergies. Eating mangoes or cashews will not work.
Contrary to popular belief, a poison ivy rash is not contagious. It cannot be spread by oozing blisters, or by scratching or touching the rash. Only direct contact with urushiol causes a reaction. (Scratching can result in an infection, however.)
The rash can appear on different parts of the body at various times. This may happen because the parts were exposed at different times, or because areas with thicker skin are less easily penetrated by the oil. The delicate skin of the genital and perianal areas, for example, is more easily breached than tougher skin on the hands.
Repeated tilling or mowing can eventually kill poison ivy plants, as can repeated applications of an herbicide like Roundup. The latter should be applied with serious caution and only on a warm, sunny day with little or no wind when the plants are actively growing.
If you are highly allergic, or wary of applying herbicides, clearing your property of the plants may be best left to a professional. While goats are said to have a hearty appetite for poison ivy plants, they may eat everything else in the yard, too.
Never try to burn a poison plant. Burning releases the toxin, which may land on skin or, worse, be inhaled and cause a serious internal reaction.
Should you contact a urushiol-containing plant, the American Academy of Dermatology recommends washing your skin immediately. Lukewarm, soapy water is best, but even plain water can limit exposure to the sap. Take care in removing contaminated clothing, and wash it separately as soon as possible.
You can relieve a rash by applying cool compresses with an astringent like Burow’s solution, soaking the affected area in colloidal oatmeal, or using calamine lotion; all are sold over the counter. Do not apply products containing a topical antihistamine, like Benadryl, which can cause a sensitivity reaction that makes matters worse.
Severe reactions may require medically prescribed treatment with an oral corticosteroid like prednisone.
Least - Welcome Sign of Summer
By Anne Marie Chaker and Anjali Athavaley : WSJ : June 22, 2010
Carolyn Walker collects and sells shade plants from her home in Bryn Mawr, Pa. There's one plant she can't seem to get rid of this year—poison ivy. "I have noticed a lot more little seedlings of it in my garden," Ms. Walker says. She and her 19-year-old son have rashes on their arms. "I normally don't get it at all," she adds.
Poison-ivy season is upon us, and the scourge of summer is shaping up for one of its most virulent and unpredictable seasons. Public gardening advisers in many regions of the country say poison-ivy complaints this year are more plentiful than in recent memory.
Poison ivy
Campers, highway crews, kids chasing baseballs into the weeds—all are at risk for an encounter with Toxicodendron radicans. "I think people are spending more time landscaping, growing vegetables and just being in their yards more," says Bob Ary, an agent with the University of Tennessee extension in Sumner County, who estimates poison-ivy queries from backyard gardeners are up about a third over last year. "There are some plants that look pretty similar to poison ivy, and inexperienced gardeners sometimes don't know how to tell the difference."
Exact numbers on poison ivy's rise are hard to pin down, because so many cases go unreported. More than 350,000 people each year suffer from poison ivy, according to a 2006 study published in the Proceedings of the National Academy of Sciences. Other estimates go higher, especially if taking poison ivy's toxic cousins, poison sumac and Western poison oak, into account.
They all produce urushiol, a skin-irritating oil that combines with skin proteins to trigger the tell-tale allergic reaction—an angry red rash that itches badly enough to make a person miss a day or more of work or fun.
About 15% of the population is insensitive to urushiol and will never develop a reaction. For everyone else, repeated exposure tends to make the rash worse. "The dermatitis gets worse each subsequent time," says Dawn Davis, a dermatologist at Mayo Clinic in Rochester, Minn. On the other hand, a person's sensitivity tends to decline with age.
There's no shortage of theories on why poison ivy seems to be rising. Some veteran gardeners think the particularly brutal winter in many regions killed off many prized perennials and shrubs—leaving more room for weeds to flourish. Another theory: more novice gardeners are zealously digging out weeds to plant vegetable patches and making contact with poison ivy.
Western poison oak
A study, published in the journal Weed Science in 2007, suggested that poison ivy is getting bigger, spreading faster and producing more urushiol as the result of increasing levels of carbon dioxide in the atmosphere. Lewis Ziska, a plant physiologist at the U.S. Agriculture Department who led the study, exposed poison ivy plants to different carbon dioxide concentrations—mirroring those that actually existed in the atmosphere at various times over several decades. The increased exposure levels produced bigger, hardier, and more irritating plants.
Poison ivy makes for an unpredictable allergen that has no comfort zone. Geralyn Caplan, an Evansville, Ind., biology teacher, says through many years of camping as a child, she never caught poison ivy. But in each of the past three years, she says, "I got nailed with it." She has been spending more time out in the yard clearing flower beds now that her kids are grown. She recently recovered from her worst case ever, when rashes and welts spread on her arms and legs.
"You might not be sensitive to it your whole life," says Dan Brown, a professor of animal nutrition and toxicology at Cornell University. "And then, Bingo."
After exposure, there is typically a 15- to 30-minute window in which you can avoid a reaction, by washing the urushiol off the skin. Several over-the-counter products can be used in this critical window and beyond, including Zanfel, a soapy wash that sells in a one-ounce tube for $39.99. Sales so far this year are running 10% to 12% ahead of the same period last year, says Steve Sisler, vice president of sales at Zanfel Laboratories Inc., of Clive, Iowa. "The season this year is moving appreciably faster than last year," he says. Washing with regular soap and warm water works, too, if done soon enough.
Prevention costs less than the cure: IvyBlock lotion, manufactured by Hyland's Inc., Los Angeles, claims to work like sun block, with a patented ingredient that absorbs urushiol before it can irritate the skin. The company says it has Food and Drug Administration approval to help prevent poison ivy, oak and sumac rashes; it retails for $12.99 for four ounces. Physicians stress the usefulness of socks and long sleeves.
If a rash develops—in most cases 12 to 72 hours after exposure—dermatologists say the first step is to try treating it at home (see "Itch Alternatives" on home remedies). An over-the-counter topical cortisone ointment, like Cortizone-10, can reduce the inflammation, and an antihistamine, like Benadryl, can relieve the itch.
Poison sumac
If that doesn't bring relief, a doctor may prescribe cortisone injections or pills. "People can have extensive blistering in large areas of the body if they have enough contact,"says Joseph Fowler, a clinical professor of dermatology at the University of Louisville School of Medicine. "You can get blisters to the point of being oozy and itchy."
A very bad scenario would be to clear poison ivy from your yard and burn it in a campfire, since it is possible to develop respiratory inflammation from breathing urushiol-laced smoke.
Recognizing poison ivy isn't easy. It can grow as a ground cover, a vine or a small bush. The leaves grow in clusters of three—hence the adage, "Leaves of three, let it be"—but the leaves can be smooth or toothed, in which case identification becomes more difficult. Western poison oak leaves are deeply cut and resemble those of a true oak tree. Poison sumac's signature is its red stems.
Poison sumac is typically found in swampy areas, especially in the South. Western poison oak is common along the Pacific coast. Poison ivy typically grows east of the Rockies, although recent reports suggest it may be spreading to places where it didn't previously thrive.
One of poison ivy's quirks is that many animals can touch or even eat it with no ill effects. "Animals not only eat it, they love it," says Jacqueline Mohan, a professor of ecology at the University of Georgia and co-author of the 2007 Weed Science study.
Pets play an important role in the spread of poison ivy. A dog with urushiol on its fur will pass it along to friendly humans who pat or rub those places.
The same sort of thing happens with camping equipment. Denis Sasseville, director of the dermatology division at McGill University, in Montreal, recalls a patient who came in every week with a new poison ivy reaction. He repeatedly told the patient to stay out of the bushes and kept showing him photos so he would know what poison ivy looked like. It didn't help. It turned out the patient, who was camping, had a sleeping bag, chairs and a tent pole covered with urushiol.
The lesson, Dr. Sasseville says: "Everything needs to be washed, because the sap stays allergenic forever."
In Junction, City, Kan., the Geary County Extension service, affiliated with Kansas State University, says poison-ivy queries to its office were up by a third last year and are running at about that same level this year. Poison-ivy calls to the Cornell University Cooperative Extension in Voorheesville, N.Y., have doubled in the past five years, says Susan Pezzolla, community educator for horticulture. "I think it's getting more prevalent," says Randy Roloff, road supervisor for Outagamie County in northeast Wisconsin. "It's spreading and tough to kill."
"Business is good," says Umar Mycka, who started a landscaping company three years ago devoted entirely to poison-ivy removal. Based in Philadelphia, he has customers from Maryland to New Jersey. "I call our method hand-to-vine combat," he says. "We get down on our hands and knees and find them, search them down to the ground and dig them up."
And then there are those people who actually like poison ivy. It's a native of North America, and its berries are an important source of food for wildlife. That explains why there are few concerted efforts to eradicate it. "We keep it out of the garden beds but let it grow elsewhere," says Eleanor Cone, a retired photography teacher in Forest Hill, Md. "One reason we garden is to create and maintain a habitat for wildlife."
By Anne Marie Chaker and Anjali Athavaley : WSJ : June 22, 2010
Carolyn Walker collects and sells shade plants from her home in Bryn Mawr, Pa. There's one plant she can't seem to get rid of this year—poison ivy. "I have noticed a lot more little seedlings of it in my garden," Ms. Walker says. She and her 19-year-old son have rashes on their arms. "I normally don't get it at all," she adds.
Poison-ivy season is upon us, and the scourge of summer is shaping up for one of its most virulent and unpredictable seasons. Public gardening advisers in many regions of the country say poison-ivy complaints this year are more plentiful than in recent memory.
Poison ivy
Campers, highway crews, kids chasing baseballs into the weeds—all are at risk for an encounter with Toxicodendron radicans. "I think people are spending more time landscaping, growing vegetables and just being in their yards more," says Bob Ary, an agent with the University of Tennessee extension in Sumner County, who estimates poison-ivy queries from backyard gardeners are up about a third over last year. "There are some plants that look pretty similar to poison ivy, and inexperienced gardeners sometimes don't know how to tell the difference."
Exact numbers on poison ivy's rise are hard to pin down, because so many cases go unreported. More than 350,000 people each year suffer from poison ivy, according to a 2006 study published in the Proceedings of the National Academy of Sciences. Other estimates go higher, especially if taking poison ivy's toxic cousins, poison sumac and Western poison oak, into account.
They all produce urushiol, a skin-irritating oil that combines with skin proteins to trigger the tell-tale allergic reaction—an angry red rash that itches badly enough to make a person miss a day or more of work or fun.
About 15% of the population is insensitive to urushiol and will never develop a reaction. For everyone else, repeated exposure tends to make the rash worse. "The dermatitis gets worse each subsequent time," says Dawn Davis, a dermatologist at Mayo Clinic in Rochester, Minn. On the other hand, a person's sensitivity tends to decline with age.
There's no shortage of theories on why poison ivy seems to be rising. Some veteran gardeners think the particularly brutal winter in many regions killed off many prized perennials and shrubs—leaving more room for weeds to flourish. Another theory: more novice gardeners are zealously digging out weeds to plant vegetable patches and making contact with poison ivy.
Western poison oak
A study, published in the journal Weed Science in 2007, suggested that poison ivy is getting bigger, spreading faster and producing more urushiol as the result of increasing levels of carbon dioxide in the atmosphere. Lewis Ziska, a plant physiologist at the U.S. Agriculture Department who led the study, exposed poison ivy plants to different carbon dioxide concentrations—mirroring those that actually existed in the atmosphere at various times over several decades. The increased exposure levels produced bigger, hardier, and more irritating plants.
Poison ivy makes for an unpredictable allergen that has no comfort zone. Geralyn Caplan, an Evansville, Ind., biology teacher, says through many years of camping as a child, she never caught poison ivy. But in each of the past three years, she says, "I got nailed with it." She has been spending more time out in the yard clearing flower beds now that her kids are grown. She recently recovered from her worst case ever, when rashes and welts spread on her arms and legs.
"You might not be sensitive to it your whole life," says Dan Brown, a professor of animal nutrition and toxicology at Cornell University. "And then, Bingo."
After exposure, there is typically a 15- to 30-minute window in which you can avoid a reaction, by washing the urushiol off the skin. Several over-the-counter products can be used in this critical window and beyond, including Zanfel, a soapy wash that sells in a one-ounce tube for $39.99. Sales so far this year are running 10% to 12% ahead of the same period last year, says Steve Sisler, vice president of sales at Zanfel Laboratories Inc., of Clive, Iowa. "The season this year is moving appreciably faster than last year," he says. Washing with regular soap and warm water works, too, if done soon enough.
Prevention costs less than the cure: IvyBlock lotion, manufactured by Hyland's Inc., Los Angeles, claims to work like sun block, with a patented ingredient that absorbs urushiol before it can irritate the skin. The company says it has Food and Drug Administration approval to help prevent poison ivy, oak and sumac rashes; it retails for $12.99 for four ounces. Physicians stress the usefulness of socks and long sleeves.
If a rash develops—in most cases 12 to 72 hours after exposure—dermatologists say the first step is to try treating it at home (see "Itch Alternatives" on home remedies). An over-the-counter topical cortisone ointment, like Cortizone-10, can reduce the inflammation, and an antihistamine, like Benadryl, can relieve the itch.
Poison sumac
If that doesn't bring relief, a doctor may prescribe cortisone injections or pills. "People can have extensive blistering in large areas of the body if they have enough contact,"says Joseph Fowler, a clinical professor of dermatology at the University of Louisville School of Medicine. "You can get blisters to the point of being oozy and itchy."
A very bad scenario would be to clear poison ivy from your yard and burn it in a campfire, since it is possible to develop respiratory inflammation from breathing urushiol-laced smoke.
Recognizing poison ivy isn't easy. It can grow as a ground cover, a vine or a small bush. The leaves grow in clusters of three—hence the adage, "Leaves of three, let it be"—but the leaves can be smooth or toothed, in which case identification becomes more difficult. Western poison oak leaves are deeply cut and resemble those of a true oak tree. Poison sumac's signature is its red stems.
Poison sumac is typically found in swampy areas, especially in the South. Western poison oak is common along the Pacific coast. Poison ivy typically grows east of the Rockies, although recent reports suggest it may be spreading to places where it didn't previously thrive.
One of poison ivy's quirks is that many animals can touch or even eat it with no ill effects. "Animals not only eat it, they love it," says Jacqueline Mohan, a professor of ecology at the University of Georgia and co-author of the 2007 Weed Science study.
Pets play an important role in the spread of poison ivy. A dog with urushiol on its fur will pass it along to friendly humans who pat or rub those places.
The same sort of thing happens with camping equipment. Denis Sasseville, director of the dermatology division at McGill University, in Montreal, recalls a patient who came in every week with a new poison ivy reaction. He repeatedly told the patient to stay out of the bushes and kept showing him photos so he would know what poison ivy looked like. It didn't help. It turned out the patient, who was camping, had a sleeping bag, chairs and a tent pole covered with urushiol.
The lesson, Dr. Sasseville says: "Everything needs to be washed, because the sap stays allergenic forever."
In Junction, City, Kan., the Geary County Extension service, affiliated with Kansas State University, says poison-ivy queries to its office were up by a third last year and are running at about that same level this year. Poison-ivy calls to the Cornell University Cooperative Extension in Voorheesville, N.Y., have doubled in the past five years, says Susan Pezzolla, community educator for horticulture. "I think it's getting more prevalent," says Randy Roloff, road supervisor for Outagamie County in northeast Wisconsin. "It's spreading and tough to kill."
"Business is good," says Umar Mycka, who started a landscaping company three years ago devoted entirely to poison-ivy removal. Based in Philadelphia, he has customers from Maryland to New Jersey. "I call our method hand-to-vine combat," he says. "We get down on our hands and knees and find them, search them down to the ground and dig them up."
And then there are those people who actually like poison ivy. It's a native of North America, and its berries are an important source of food for wildlife. That explains why there are few concerted efforts to eradicate it. "We keep it out of the garden beds but let it grow elsewhere," says Eleanor Cone, a retired photography teacher in Forest Hill, Md. "One reason we garden is to create and maintain a habitat for wildlife."
Poison ivy rash
:
Everything you may want to know
By Mayo Clinic staff
Definition:
Poison ivy rash
A poison ivy rash is a type of skin irritation called allergic contact dermatitis. Poison ivy rash is caused by a sensitivity to an irritant found in poison ivy and similar toxic plants, such as poison oak and poison sumac. Each of these plants contains an oily resin called urushiol (u-ROO-she-ol) that can irritate the skin and cause a rash.
Although the itching from a poison ivy rash can be quite bothersome, the good news is that a poison ivy rash or one caused by poison oak or poison sumac generally isn't serious. Poison ivy rash treatment consists of self-care methods to relieve itching until the reaction disappears.
Symptoms:
Poison ivy rash
Poison ivy blisters
Signs and symptoms of a poison ivy rash include:
The reaction usually develops 12 to 48 hours after exposure and can last up to eight weeks. The severity of the rash is dependent on the amount of urushiol that gets on your skin.
In severe cases, new areas of rash may break out several days or more after initial exposure. This may seem like the rash is spreading. But it's more likely due to the rate at which your skin absorbed the urushiol.
Your skin must come in direct contact with the plant's oil to be affected. Blister fluid from scratching doesn't spread the rash, but germs under your fingernails can cause a secondary bacterial infection.
When to see a doctor:
See your doctor if any of the following occur:
Causes:
Poison ivy plant
Poison ivy plant with berries
Poison oak plant
Poison sumac plant
All cause contact dermatitis and the resulting itchy rash.
You can get a poison ivy reaction from:
Complications:
Scratching a poison ivy rash with dirty fingernails may cause a secondary bacterial infection. This might cause pus to start oozing from the blisters. See your doctor if this happens. Treatment for a secondary infection generally includes antibiotics.
Preparing for your appointment:
You probably won't need medical treatment for a poison ivy rash, unless the rash persists for more than a few weeks or you think you may have a bacterial infection too.
What you can do in the meantime:
A poison ivy rash will eventually go away on its own. But, the itching can be difficult to deal with. Here are some steps you can take to help control the itching:
Tests and diagnosis:
You generally won't need to see your doctor for a poison ivy rash. However, if you do visit your doctor, he or she will be able to diagnose your rash by looking at it. No further testing is needed.
Treatments and drugs:
Poison ivy treatments are usually limited to self-care methods, and the rash typically goes away on its own within two to four weeks. In the meantime, you can use poison ivy remedies, such as oatmeal baths and cool compresses, as well as over-the-counter anti-itch medications to relieve your signs and symptoms.
If the rash is widespread or results in a large number of blisters, your doctor may prescribe an oral corticosteroid, such as prednisone, for poison ivy treatment. If a bacterial infection has developed at the rash site, your doctor will likely give you a prescription for an oral antibiotic.
Lifestyle and home remedies:
Once a rash has broken out, the following poison ivy remedies may help to soothe itching and swelling:
Prevention:
The advice "Leaves of three, let them be" is familiar to many people, with good reason. It's a reminder to stay away from plants that feature three leaflets to a stem, such as poison ivy, because avoiding contact is the best way to prevent an allergic reaction.
These suggestions may help you avoid a rash from these irritating plants:
Everything you may want to know
By Mayo Clinic staff
Definition:
Poison ivy rash
A poison ivy rash is a type of skin irritation called allergic contact dermatitis. Poison ivy rash is caused by a sensitivity to an irritant found in poison ivy and similar toxic plants, such as poison oak and poison sumac. Each of these plants contains an oily resin called urushiol (u-ROO-she-ol) that can irritate the skin and cause a rash.
Although the itching from a poison ivy rash can be quite bothersome, the good news is that a poison ivy rash or one caused by poison oak or poison sumac generally isn't serious. Poison ivy rash treatment consists of self-care methods to relieve itching until the reaction disappears.
Symptoms:
Poison ivy rash
Poison ivy blisters
Signs and symptoms of a poison ivy rash include:
- Redness
- Itching
- Swelling
- Blisters
The reaction usually develops 12 to 48 hours after exposure and can last up to eight weeks. The severity of the rash is dependent on the amount of urushiol that gets on your skin.
In severe cases, new areas of rash may break out several days or more after initial exposure. This may seem like the rash is spreading. But it's more likely due to the rate at which your skin absorbed the urushiol.
Your skin must come in direct contact with the plant's oil to be affected. Blister fluid from scratching doesn't spread the rash, but germs under your fingernails can cause a secondary bacterial infection.
When to see a doctor:
See your doctor if any of the following occur:
- The reaction is severe or widespread.
- The rash affects sensitive areas of your body, such as your eyes, mouth or genitals.
- Blisters are oozing pus.
- You develop a fever greater than 100 F (37.8 C).
- The rash doesn't get better within a few weeks.
Causes:
Poison ivy plant
Poison ivy plant with berries
Poison oak plant
Poison sumac plant
All cause contact dermatitis and the resulting itchy rash.
- Poison ivy is an extremely common weed-like plant that may grow as a bush, plant or thick, tree-climbing vine. The leaves typically grow three leaflets to a stem. Some leaves have smooth edges, while others have a jagged, tooth-like appearance. In the fall, the leaves may turn yellow, orange or red. Poison ivy can produce small, greenish flowers and green or off-white berries.
- Poison oak can grow as a low plant or bush, and its leaves resemble oak leaves. Like poison ivy, poison oak typically grows three leaflets to a stem. Poison oak may have yellow-white berries.
- Poison sumac may be a bush or a small tree. It has two rows of leaflets on each stem and a leaflet at the tip.
You can get a poison ivy reaction from:
- Direct touch. If you directly touch the leaves, stem, roots or berries of the plant, shrub or vine, you may have a reaction.
- Urushiol remaining on your skin. You may develop a poison ivy rash after unknowingly rubbing the urushiol onto other areas of your skin. For example, if you walk through some poison ivy then later touch your shoes, you may get some urushiol on your hands, which you may then transfer to your face by touching or rubbing.
- Urushiol on objects. If you touch urushiol left on an item, such as clothing or firewood, you may have a reaction. Although animals usually aren't affected by urushiol, if it's on your pet's fur and you touch your pet, you may develop a poison ivy rash. Urushiol can remain allergenic for years, especially if kept in a dry environment. So if you put away a contaminated jacket without washing it and take it out a year later, the oil on the jacket may still cause a reaction.
- Inhaling smoke from burning poison ivy, oak or sumac plants. Even the smoke from burned poison ivy, poison oak and poison sumac contains the oil and can irritate or injure your eyes or nasal passages.
Complications:
Scratching a poison ivy rash with dirty fingernails may cause a secondary bacterial infection. This might cause pus to start oozing from the blisters. See your doctor if this happens. Treatment for a secondary infection generally includes antibiotics.
Preparing for your appointment:
You probably won't need medical treatment for a poison ivy rash, unless the rash persists for more than a few weeks or you think you may have a bacterial infection too.
What you can do in the meantime:
A poison ivy rash will eventually go away on its own. But, the itching can be difficult to deal with. Here are some steps you can take to help control the itching:
- Apply an over-the-counter corticosteroid cream, hydrocortisone 1%, (Cortaid-1) for the first few days.
- Apply calamine lotion.
- Take oral antihistamines, such as loratatine 10mg (Claritin), cetirizine 10mg (Zyrtec) or diphenhydramine 25mg (Benadryl), which may also help you sleep better.
- Soak in a cool-water bath containing a colloidal oatmeal product (Aveeno) or baking soda.
- Place cool, wet compresses on the affected area for 15 to 30 minutes several times a day.
Tests and diagnosis:
You generally won't need to see your doctor for a poison ivy rash. However, if you do visit your doctor, he or she will be able to diagnose your rash by looking at it. No further testing is needed.
Treatments and drugs:
Poison ivy treatments are usually limited to self-care methods, and the rash typically goes away on its own within two to four weeks. In the meantime, you can use poison ivy remedies, such as oatmeal baths and cool compresses, as well as over-the-counter anti-itch medications to relieve your signs and symptoms.
If the rash is widespread or results in a large number of blisters, your doctor may prescribe an oral corticosteroid, such as prednisone, for poison ivy treatment. If a bacterial infection has developed at the rash site, your doctor will likely give you a prescription for an oral antibiotic.
Lifestyle and home remedies:
Once a rash has broken out, the following poison ivy remedies may help to soothe itching and swelling:
- Over-the-counter low-potency corticosteroid creams, such as hydrocortisone 1%, applied two to four times a day
- Calamine lotion
- Oral antihistamines, such as loratidine 10mg (Claritin), cetirizine 10mg (Zyrtec) and diphenhydramine 25mg (Benadryl), which may also help you sleep better
- Cool-water tub soaks with over-the-counter colloidal oatmeal (Aveeno) or baking soda
- Cool, wet compresses for 15 to 30 minutes several times a day
Prevention:
The advice "Leaves of three, let them be" is familiar to many people, with good reason. It's a reminder to stay away from plants that feature three leaflets to a stem, such as poison ivy, because avoiding contact is the best way to prevent an allergic reaction.
These suggestions may help you avoid a rash from these irritating plants:
- Identify poison ivy, poison oak and poison sumac: Learn what the plants and leaves look like and where they're commonly found so that you can avoid them.
- Take precautions outdoors: When hiking or engaging in other activities that might expose you to poison ivy, try to stay on cleared pathways. If camping, make sure you pitch your tent in an area free of poisonous plants. Keep pets from running through wooded areas so that urushiol doesn't accidentally stick to their fur, which you then may touch. If you think your pet may have run through poison ivy, oak or sumac, put on some long rubber gloves and give your pet a bath to remove any residual urushiol.
- Remove poison ivy: In your backyard, you can use an herbicide to get rid of poison ivy or use heavy gloves to carefully pull it out of the ground. Note that even dead plants can cause a reaction. Afterward, remove and wash your gloves and hands thoroughly. Don't burn poison ivy or related plants because the urushiol can be carried by the smoke and cause irritation or injury.
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Clean anything that may be contaminated: Wearing long
pants, socks, shoes and gloves will help protect your skin, but be sure
to wash your clothing promptly with detergent — in a washing machine, if
possible — if you think you've come into contact with poison ivy.
Handle contaminated clothes carefully so that you don't transfer the
urushiol to furniture, rugs or appliances.
In addition, wash any other contaminated items, such as outdoor gear, garden tools, jewelry, shoes and even shoelaces, as soon as possible. If you must wait to wash any contaminated items, seal them up in a plastic bag or container to avoid contamination of other items. Dry cleaning also will get rid of urushiol, but be sure to let your dry cleaner know that the item may have been exposed to poison ivy.
- Wash your skin with soap and water: Gently washing off the harmful resin from your skin, using any type of soak, within five to 10 minutes after exposure may help avert a reaction. After an hour or so, however, the urushiol has usually penetrated the skin and washing won't necessarily prevent a reaction, but it may help reduce its severity. Be sure to wash under your fingernails too.
- Apply a barrier cream: Appy an over-the-counter barrier skin cream containing bentoquatam (Ivy Block) to protect your skin. Bentoquatam absorbs urushiol and prevents or lessens your skin's reaction to the oil.
