Poison Oak   THIS ARTICLE IS MEANT TO BE  A REFERENCE ONLY SEE YOUR DOCTOR IMMEDIATELY IF YOU SEE SYMPTOMS.   IDENTIFICATION  Poison oak, Toxicodendron diversilobum, is a deciduous (loses leaves in winter), woody plant that can have a shrub or vine form. In open areas under full sunlight, poison oak forms a dense leafy shrub usually one to six feet in height. In shaded areas, such as in redwood and oak woodlands, it becomes a much taller climbing vine. Leaves normally consist of three leaflets with the stalk of the central leaflet being longer than those of the other two. In spring, poison oak produces small, white-green flowers. Whitish-green, round fruit form in late summer. In early spring the young leaves are green or sometimes light red. In late spring and summer the foliage is glossy green, and later turns attractive shades of orange and red. IMPACT  While it can reduce optimal grazing area in rangeland or pastures, the primary concern associated with poison oak is the allergic reaction it causes in many people. In California , the number of working hours lost as a result of dermatitis caused by poison oak makes it the most hazardous plant in the state. Contact with poison oak leaves or stems at any time of the year can cause an allergic response. Even cut branches can remain toxic for 18 months. Unwashed, contaminated clothing can retain toxicity for more than one year. When the allergen contacts the skin surface, it is rapidly absorbed into the surrounding cells. Within one to six days, skin irritation and itching will be followed by water blisters. Contrary to popular belief, the exuded material from the blisters does not contain the allergen and does not transmit the rash to other regions of the body or to other individuals. However, scratching other parts of the body with contaminated fingernails can spread poison oak. In addition to direct contact with the plant, transmission of the allergen can occur from a number of other sources including smoke particles, contact with objects such as clothing, gloves, and tools, or contact with animals, particularly pets. Never burn poison oak. After coming in contact with the allergen, the best way to prevent skin irritation is to pour a mild solvent, such as isopropyl alcohol (rubbing alcohol), over the exposed area and then follow this with plenty of cold water (warm water enhances penetration of the oil) within a few minutes of exposure. If isopropyl alcohol is not available, just wash with lots of cold water, but you need to wash within five minutes of exposure to prevent a rash. Even if it is too late to prevent the rash, washing the skin to remove excess plant oil will keep the rash from spreading. The poison oak toxin is oil, so it does not dissolve in water. Sufficient quantities of water, however, will dilute the oil to the point where it is no longer harmful. Using only a small amount of water or disposable hand wipes is more likely to spread the toxin than remove it. Soaps can be used to wash, but only if used with copious amounts of water; otherwise, they too will spread the toxin. If a rash develops after exposure to poison oak, the use of a product called Tecnu, which is sold at most drug stores, will relieve the itch and reduce the rash. When applied once a day, it stops the itching for most of the day and clears up the rash in about seven days.    MANAGEMENT  The primary ways of managing poison oak are mechanical removal by hand pulling (not recommended for individuals who are sensitive to poison oak) and treatment with herbicides.  Mechanical  Hand pulling or mechanical grubbing (using a shovel, pick, etc.) can be used to physically remove plants located in a yard or near houses. Remove plants in early spring or late fall when the soil is moist and the rootstalks are easily dislodged. Grubbing when the soil is dry and hard will usually break off the stems, leaving the rootstalks to vigorously resprout. Whether the individual is sensitive or believed to be immune, he or she should wear appropriate protective clothing, including washable cotton gloves over plastic gloves, when handling the plants. Wash all clothing thoroughly, including shoes, after exposure. Mowing has little effect in poison oak control, unless it is performed repeatedly (at least four times during the growing season), because of the underground rootstalks. A single plowing is of no value and often serves to propagate the shrub.  Chemical Control  Herbicides used to control poison oak in California include glyphosate (Roundup, etc.) and the herbicides triclopyr (Garlon, Ortho Brush-B-Gon, etc.), 2,4-D (Spurge & Oxalis Killer, etc.), and dicamba (Banvel, Spurge & Oxalis Killer, etc.). These herbicides can be applied as stump or basal applications, or as a foliar spray. Glyphosate should be applied late in the growth cycle, after fruit have formed, but before leaves lose their green color. It is important to note that glyphosate is a nonselective compound and will damage or kill other vegetation it contacts. Other herbicides, such as triclopyr, 2,4-D, dicamba, and combinations of these herbicides, are also used to control poison oak. The application timing with these herbicides is somewhat different than for glyphosate: applications can be made earlier than with glyphosate, when plants are growing rapidly from spring to midsummer.   Triclopyr is the most effective of these herbicides for control of poison oak. A new herbicide in California , imazapyr, is also very effective for the control of poison oak, but is only available for application by licensed pesticide applicators.  Stump Application  Stump treatments are most effective during periods of active growth. Cut stems of poison oak one to two inches above the soil surface, and immediately after cutting, treat the stump. A delay in treatment will result in poor control. Be sure to completely cover all surfaces of the stumps with the herbicide until it runs down the base of the stubs. Spray any regrowth from cut stumps with a foliar spray when the leaves fully expand. Foliar application of herbicides to poison oak is most effective when done during the flowering stage. Do not apply foliar herbicides before plants begin growth in spring or after the leaves have begun to turn yellow or red in late summer or fall. One application of a herbicide usually does not completely control poison oak. Re-treat when new, sprouting leaves are fully expanded, generally when the plants are about two feet tall. Watch treated areas closely for at least a year and re-treat as necessary. Be sure to read and follow all label directions with the use of any herbicide.     Approximately 85 percent of the population will develop an allergic reaction if exposed to poison ivy, oak or sumac, according to the American Academy of Dermatology. Nearly one-third of forestry workers and firefighters who battle forest fires in California , Oregon and Washington develop rashes or lung irritations from contact with poison oak, which is the most common of the three in those states. Usually, people develop a sensitivity to poison ivy, oak or sumac only after several encounters with the plants, sometimes over many years. However, sensitivity may occur after only one exposure. The cause of the rash, blisters, and infamous itch is urushiol (pronounced oo-roo-shee-ohl), a chemical in the sap of poison ivy, oak and sumac plants. Because urushiol is inside the plant, brushing against an intact plant will not cause a reaction. But undamaged plants are rare. "Poison oak, ivy and sumac are very fragile plants," says. Stems or leaves broken by the wind or animals, and even the tiny holes made by chewing insects, can release urushiol. Reactions, treatments and preventive measures are the same for all three poison plants. Avoiding direct contact with the plants reduces the risk but doesn't guarantee against a reaction. Urushiol can stick to pets, garden tools, balls, or anything it comes in contact with. If the urushiol isn't washed off those objects or animals, just touching them--for example, picking up a ball or petting a dog--could cause a reaction in a susceptible person. (Animals, except for a few higher primates, are not sensitive to urushiol.) Urushiol that's rubbed off the plants onto other things can remain potent for years, depending on the environment. If the contaminated object is in a dry environment, the potency of the urushiol can last for decades, says Epstein. Even if the environment is warm and moist, the urushiol could still cause a reaction a year later. "One of the stories I tell people is of the hunter who gets poison oak on his hunting coat," says Epstein. "He puts it on a year later to go hunting and gets a rash [from the urushiol still on the coat]." Almost all parts of the body are vulnerable to the sticky urushiol, producing the characteristic linear (in a line) rash. Because the urushiol must penetrate the skin to cause a reaction, places where the skin is thick, such as the soles of the feet and the palms of the hands, are less sensitive to the sap than areas where the skin is thinner. The severity of the reaction may also depend on how big a dose of urushiol the person got.   Quick Action Needed  Because urushiol can penetrate the skin within minutes, there's no time to waste if you know you've been exposed. "The earlier you cleanse the skin, the greater the chance that you can remove the urushiol before it gets attached to the skin," says Hon-Sum Ko, M.D., an allergist and immunologist with FDA's Center for Drug Evaluation and Research. Cleansing may not stop the initial outbreak of the rash if more than 10 minutes has elapsed, but it can help prevent further spread. If you've been exposed to poison ivy, oak or sumac, if possible, stay outdoors until you complete the first two steps: ·                           First, Epstein says, cleanse exposed skin with generous amounts of isopropyl (rubbing) alcohol. (Don't return to the woods or yard the same day. Alcohol removes your skin's protection along with the urushiol and any new contact will cause the urushiol to penetrate twice as fast.) ·                           Second, wash skin with water. (Water temperature does not matter; if you're outside, it's likely only cold water will be available.) ·                           Third, take a regular shower with soap and warm water. Do not use soap before this point because "soap will tend to pick up some of the urushiol from the surface of the skin and move it around," says Epstein. ·                           Clothes, shoes, tools, and anything else that may have been in contact with the urushiol should be wiped off with alcohol and water. Be sure to wear gloves or otherwise cover your hands while doing this and then discard the hand covering. Dealing with the Rash  If you don't cleanse quickly enough, or your skin is so sensitive that cleansing didn't help, redness and swelling will appear in about 12 to 48 hours. Blisters and itching will follow. For those rare people who react after their very first exposure, the rash appears after seven to 10 days. Because they don't contain urushiol, the oozing blisters are not contagious nor can the fluid cause further spread on the affected person's body. Nevertheless, Epstein advises against scratching the blisters because fingernails may carry germs that could cause an infection. The rash will only occur where urushiol has touched the skin; it doesn't spread throughout the body. However, the rash may seem to spread if it appears over time instead of all at once. This is either because the urushiol is absorbed at different rates in different parts of the body or because of repeated exposure to contaminated objects or urushiol trapped under the fingernails. The rash, blisters and itch normally disappear in 14 to 20 days without any treatment. But few can handle the itch without some relief. For mild cases, wet compresses or soaking in cool water may be effective. Oral antihistamines can also relieve itching. FDA also considers over-the-counter topical corticosteroids (commonly called hydrocortisones under brand names such as Cortaid and Lanacort) safe and effective for temporary relief of itching associated with poison ivy. For severe cases, prescription topical corticosteroid drugs can halt the reaction, but only if treatment begins within a few hours of exposure. "After the blisters form, the [topical] steroid isn't going to do much," says Epstein. The American Academy of Dermatology recommends that people who have had severe reactions in the past should contact a dermatologist as soon as possible after a new exposure. Severe reactions can be treated with prescription oral corticosteroids. There are a number of OTC products to help dry up the oozing blisters, including:             ·                           aluminum acetate (Burrows solution)         ·                           baking soda         ·                           Aveeno (oatmeal bath)         ·                           aluminum hydroxide gel         ·                           calamine         ·                           kaolin         ·                           zinc acetate          ·                           zinc carbonate         ·                           zinc oxide Desensitization, vaccines, and barrier creams have been studied over the last several decades for their potential to protect against poison ivy reactions, but none have been approved by FDA for this purpose. Right now, prevention seems the best treatment.   Getting Rid of the Plants Poison ivy, oak and sumac are most dangerous in the spring and summer, when there is plenty of sap, the urushiol content is high, and the plants are easily bruised. However, the danger doesn't disappear over the winter. Dormant plants can still cause reactions, and cases have been reported in people who used the twigs of the plant for firewood or the vines for Christmas wreaths. Even dead plants can cause a reaction, because urushiol remains active for several years after the plant dies. If poison ivy invades your yard, "there's really no good news for you," says David Yost, a horticulturist (specialist in fruits, vegetables, flowers, and general gardening) with the state of Virginia . The two herbicides most commonly used for poison ivy--Roundup and Ortho Poison Ivy Killer--will kill other plants as well. Spraying Roundup (active ingredient glyphosate) on the foliage of young plants will kill the poison ivy, but if the poison ivy vine is growing up your prize rhododendron or azalea, for example, the Roundup will kill them too, he says. Ortho Poison Ivy Killer (active ingredient triclopyr), if used sparingly, will kill poison ivy but not trees it grows around, says Joseph Neal, Ph.D., associate professor of weed science, Cornell University. "But don't use it around shrubs, broadleaf ground cover, or herbaceous garden plants," he says. Neal explains it is possible to spray the poison ivy without killing other plants if you pull the poison ivy vines away from the desirable plants and wipe the ivy foliage with the herbicide, or use a shield on the sprayer to direct the chemical. If you don't want to use chemicals, "manual removal will get rid of the ivy if you're diligent," says Neal. You must get every bit of the plant--leaves, vines, and roots--or it will sprout again. The plants should be thrown away according to your municipality's regulations, says Neal. Although urushiol will break down with composting, Neal doesn't recommend that because the plants must be chopped into small pieces first, which just adds to the time you're exposed to the plant and risk of a rash. "It's a health issue," he says. Never burn the plants. The urushiol can spread in the smoke and cause serious lung irritation. The American Academy of Dermatology recommends that whenever you're going to be around poison ivy--trying to clear it from your yard or hiking in the woods--you wear long pants and long sleeves and, if possible, gloves and boots. Neal recommends wearing plastic gloves over cotton gloves when pulling the plants. Plastic alone isn't enough because the plastic rips, and cotton alone won't work because after a while the urushiol will soak through.   Identification Unfortunately, poison ivy, oak and sumac don't grow with little picture ID badges around their stems, so you have to know what to look for. The famous rule "leaves of three, let it be" is good to follow, except that some of the plants don't always play by the rules and have leaves in groups of five to nine. To avoid these plants and their itchy consequences, here's what to look for.  Poison Oak        ·     grows to 6-foot-tall clumps or vines up to 30 feet long                  oak-like leaves, usually in clusters of three        ·        clusters of yellow berries