The poison ivy plant, poison oak and poison sumac can be a big pain...
especially for gardeners, campers, hikers, and others who enjoy the outdoors.

The cause of the rash, blisters, and itch is urushiol, 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 William L. Epstein, M.D., professor of dermatology, University of California, San Francisco. 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.The severity
of the reaction may also depend on how big a dose of urushiol the person got.

Because urushiol can penetrate the skin within minutes, there's no time to waste if you know you've been exposed. Cleansing the skin in the first 10 minutes may not stop the outbreak of the rash, but it can help
prevent more spreading.

Stay outdoors if possible, until you complete the first two steps:
1. Cleanse exposed skin with generous amounts of isopropyl (rubbing) alcohol. Keeping in mind you should not return to
the yard or the woods the same day because the alcohol removes your skin's protection along with the urushiol. Any new contact will cause the urushiol to penetrate twice as fast.

2. Wash skin with water. Do not use soap at this point because "soap tends to pick up some of the urushiol from the surface of the skin and move it around," says Epstein.

3. Take a regular shower with soap and warm water.

4. Anything that may have been in contact with the urushiol, such as clothes, shoes or tools should be wiped off with alcohol and water. Wear gloves while doing this and then discard the gloves.

Dealing with the Rash
If you are didn't cleanse quickly enough or your skin is very sensitive, redness and swelling will appear in 12 to 48 hours. Next blisters and itching. The rash appears after seven to ten days for those rare people who react after their very first exposure.

Because blisters don't contain urushiol they are not contagious, nor can the fluid cause further spread on the affected person's body. Epstein advises not to scratch blisters because your fingernail may carry germs that could cause an infection.

Without any treatment the rash, blisters and itching normally disappears in 14 to 20 days. Few people can deal with the
itch without some relief.

Mild cases
• Use a wet compress or soaking in cool water may help
• Oral antihistamines
• 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.

Severe cases
If treatment begins within a few hours of exposure - prescription topical corticosteroid drugs can halt the reaction, but only .
"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. Phillip M. Williford, M.D., assistant professor of dermatology, Wake Forest University, prescribes oral corticosteroids if the rash is on the face, genitals, or covers more than 30 percent of the body. The drug must be taken for at least 14 days, and preferably over a three-week period, says FDA's Ko. Shorter courses of treatment, he warns, will cause a rebound with an even more severe rash.

Over-the-counter products to help dry up the oozing blisters
• Aluminum acetate (Burrows solution)
• Baking soda
• Aveeno (oatmeal bath)
• Aluminum hydroxide gel
• Calamine
• Kaolin
• Zinc acetate
• Zinc carbonate
• Zinc oxide

Prevention is the best treatment
During the spring and summer, poison ivy, oak and sumac are most dangerous. The urushiol content is high and plants are easily bruised. In the winter, dormant and even dead plants can still cause reactions, because urushiol remains active for several years after the plant dies.

Using chemicals
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 next to your zinnias, Roundup will kill them too.

Used sparingly, Ortho Poison Ivy Killer (active ingredient triclopyr) will kill poison ivy but not trees it grows around. Don't use it around ground cover, garden plants or shrubs.

Using the herbicide on the poison ivy without killing other plants:
• Pull the poison ivy vines away from your plants and wipe the ivy foliage with the herbicide.
• Use a shield on the sprayer and direct the chemical right onto the poison ivy.

Don't want to use chemicals?
• If you are going to manually remove poison ivy, you must be diligent. Every bit of the plant, the leaves, vines and even roots must be pulled out, or they will sprout again.

The American Academy of Dermatology recommends wearing long pants and long sleeves, gloves and boots. It's also a good idea to wear 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.

Where do you put the plants you pull up?

The plants should be thrown away according to your municipality's regulations.

Never burn the plants. The urushiol can spread in the smoke and cause serious lung irritation.

Poison Ivy • Grows around lakes and streams in the Midwest and the East • Woody, ropelike vine, a trailing shrub on the ground, or a free-standing shrub • Normally three leaflets (groups of leaves all on the same small stem coming off the larger main stem), but may vary from groups of three to nine • Leaves are green in the summer and red in the fall • Yellow or green flowers and white berries	Poison Oak • Eastern (from New Jersey to Texas) grows as a low shrub; Western (along the Pacific coast) 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	Poison Sumac • Grows in boggy areas, especially in the Southeast • Rangy shrub up to 15 feet tall • Seven to 13 smooth-edged leaflets • Glossy pale yellow or cream-colored berries

Source: FDA

For more information:
Mayo clinic