Exposure to poison ivy is one of the most common causes of an allergic skin rash. This reaction is caused by exposure to the chemical oil "urushiol" which is found in the roots, stems and leaves of the plant. After coming into contact with poison ivy, most individuals will develop a moderate to severe itch followed by a raised red rash. This rash may develop into fluid-filled bumps or blisters usually arranged in a straight line or circular fashion.

Poison ivy can be found in every area of the United States (although it's rare in the Southwest, Hawaii and Alaska). It generally grows as a vine or shrub in wooded areas, open fields or along the roadside. The plant has three almond-shaped pointed leaves with two of the leaves having very short stems which grow directly opposite to each other. The leaves can be green, red or orange (depending on the time of year) and may even bear small "pumpkin-shaped" fruit.

Facts & Fiction:

Urushiol oil is absorbed directly into the skin within minutes of contact. If you believe you have come in contact with the plant, shower immediately and scrub the areas with soap. This will decrease the likelihood of developing a severe reaction.

Urushiol oil can also be carried on your clothes and pets. Wash your clothes as soon as possible to avoid the risk of additional exposure. Pets will not develop the rash, but can spread the oil to your skin. Pet shampoos are available which remove the oil from their fur. However, make certain you use gloves while cleaning your pet or you risk further exposure to the oil.

The rash of poison ivy is not contagious. The "sticky" fluid inside the rash is a result of our own immune system reacting to the oil. Once a person washes the exposed areas, the risk of transmission to another individual is essentially zero.

Although the rash may appear to spread, don't panic. This is due to the amount and timing of exposure to the oil. Thus, the areas of skin with the greatest contact to the urushiol will appear to develop the rash first and will probably have the most severe symptoms.

If the rash is severe, visit your physician. He or she may prescribe steroids (by mouth or by an injection) to treat the reaction. This type of treatment rapidly improves symptoms. However, it is common to need to take the steroids for up to 10 days to prevent the allergic component of the rash from recurring.

Since the rash may compromise the integrity of the skin, there is a risk of developing a bacterial infection. If the rash becomes painful, blanches or you develop fevers or chills, visit your doctor immediately. You may need antibiotics to fight off the infection.

In general, the more someone is exposed to the plant, the more likely a severe rash will develop. Additionally, although someone may appear to be "immune" to getting a rash from exposures, that immunity is not necessarily permanent.

Do not burn poison ivy plants as inhaling the smoke can create a life-threatening lung reaction, often requiring hospitalization. Be cautious when burning brush piles.

Leave removal of the plant to a professional. Too many people develop a severe case of poison ivy in an effort to clear it from their yard.

The best treatment is avoidance. However, if you are exposed and develop a rash, there are things which can make the symptoms less severe.

Antihistamine pills (e.g. Benadryl or Zyrtec) may decrease the itch of poison ivy.

Calamine lotion may cool the skin, thereby reducing the severity of the itch.

Don't scratch. Scratching irritates the skin, causing the symptoms to increase and may increase the risk of infection.

Gently rub an ice cube over the rash. The cooling effect reduces the inflammation and itch.

Over-the-counter cortisone creams (e.g. Cortaid) may reduce the inflammation and shorten the duration of the rash. Never use cortisone cream on the face.

Take a cool or lukewarm bath. A cool environment tends to reduce the itch.

If a severe rash occurs, visit your doctor. Severe cases can lead to serious skin infections. Poison ivy can be a real nuisance, but always remember the old adage: "Leaves of three -- let them be."

Dr. Michael Schwartz is board certified in internal medicine with a private practice in Darien. For comments or questions, please visit his website at www.drmichaelbschwartz.com.

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