How to identify poison ivy:

Identifying the poison ivy plant is the first step in avoiding the rash. Poison ivy is often very difficult to spot. It closely resembles several other common garden plants, and can blend in with other plants and weeds.

• The popular saying “leaves of three, let it be” is a good rule of thumb for poison ivy but is only partly correct.
• A more exact saying would be “leaflets of three, let it be,” because each leaf has three leaflets.
• It is most often found in moist areas, such as riverbanks, woods, and pastures.
• The edges of the leaves are generally smooth or have tiny "teeth."
• Their color changes based on the season -- reddish in the spring; green in the summer; and yellow, orange, or red in the fall.

What causes the allergic reaction?

The culprit behind the rash is a chemical in the sap of poison ivy plants called urushiol (oo-roo-shee-ohl).

• Urushiol is:
• Found in the sap of poisonous plants like poison ivy, poison oak, and poison sumac.
• In all parts of the poison ivy plant -- the leaves, stems, and roots.
• A nearly invisible oil, sticks to almost all surfaces, and does not dry.
• People can come into contact with poison ivy in 3 ways:
• Direct contact — touching the sap of the toxic plant.
• Indirect contact — touching something on which urushiol is present. The oil can stick to the fur of animals, clothing, garden tools or sports equipment, or to any objects that have come into contact with it.
• Airborne contact — burning poisoned plants puts urushiol particles into the air.
• Only a tiny amount of this chemical -- 1 billionth of a gram -- is enough to cause a rash in many people.
• Sometimes the allergy doesn't emerge until you've been exposed several times, and some people develop a rash after their very first exposure.
• It may take up to ten days for the rash to emerge the first time.

About the rash:

The poison ivy rash often looks like red lines, and sometimes it forms blisters.

When urushiol gets on the skin, it begins to penetrate in minutes. A reaction appears, usually within 12 to 48 hours. There is severe itching, redness, and swelling, followed by blisters. The rash is often arranged in streaks or lines where the person brushed against the plant. In a few days, the blisters become crusted and take 10 days or longer to heal.

Treatment

If you think you’ve had a brush with poison ivy, poison oak, or poison sumac, follow these simple steps:

• Wash all exposed areas with cold running water as soon as you can reach a stream, lake, or garden hose. If you can do this within five minutes, the water may keep the urushiol from contacting your skin and spreading to other parts of your body. Within the first 30 minutes, soap and water are helpful.
• Relieve the itching of mild rashes by taking cool showers and applying over-the-counter preparations like calamine lotion. Soaking in a lukewarm bath with an oatmeal or baking soda solution may also ease itching and dry oozing blisters. Over-the-counter hydrocortisone creams are not strong enough to have much effect on poison ivy rashes. Oral antihistamines may help too.
• Wash your clothing in a washing machine with detergent. If you bring the clothes into your house, be careful that you do not transfer the urushiol to rugs or furniture. Because urushiol can remain active for months, wash camping, sporting, fishing, or hunting gear that was in contact with the oil.

Common Myths:

Scratching poison ivy blisters will spread the rash.
False. The fluid in the blisters will not spread the rash. The rash is spread only by urushiol. For instance, if you have urushiol on your hands, scratching your nose or wiping your forehead will cause a rash in those areas even though leaves did not contact the face. Avoid excessive scratching of your blisters. Your fingernails may carry bacteria that could cause an infection.

Once allergic, always allergic to poison ivy.
False. A person’s sensitivity changes over time, even from season to season. People who were sensitive to poison ivy as children may not be allergic as adults.

Dead poison ivy plants are no longer toxic.
False. Urushiol remains active for up to several years. Never handle dead plants that look like poison ivy.