Some essential facts about poison ivy and poison oak rashes:

• Identifying: Poison ivy is found in forested areas across the much of the United States and Canada. Poison oak is common in southern states. Both plants can be identified by their distinctive sets of three leaves on a stem. Poison ivy leaves have pointy ends, while poison oak has oak-like scalloping at the leaf edges. While more commonly recognized as shrubs, both plants can also grow up trees as vines.

• Poison ivy and oak release a resin called urushiol, and it’s contact with that resin that leads to the rash. Experts say more than half the population of the U.S. and Canada are susceptible to reacting to poison ivy’s urushiol.

• Signs: A poison ivy rash typically occurs within 24 hours, though sometimes it will develop as late as 3 days after exposure. (An old wives’ tale is that the rash appears immediately – not so.) Unfortunately, the symptoms can last for 2 to 3 weeks.

• The rash: in most people, the rash looks like strips of tiny pimple-like blisters and is irritating and uncomfortable. But for some who are highly sensitive to poison ivy, the rash can turn into large, liquid-filled blisters and is extremely itchy and painful.

• Myths: Contrary to what you may hear or see on the Internet, the rash is not contagious and it does not spread. It just seems as if spreading is occurring, since resin absorbed by the skin may slowly cause increasing blistering.

Next: Treatment and Prevention

Dr. Skotnicki: The rash you get from touching poison ivy is an allergic response to the plant’s resin, called urushiol. Poison ivy allergic contact dermatitis usually appears 24 hours after exposure and can range from being mildly red, swollen and itchy to severe vesicles (bubbles of liquid) and large blisters.

This is an allergy that’s quite common. However, it is a specific immune response and not every person who touches the plant will react. Repeat exposure to the plant can lead to sensitization and a lifelong allergy. With each contact the allergic response can become worse, leading to more severe dermatitis.

The allergy is not life-threatening, but can be quite uncomfortable.

The best way to treat poison ivy allergic contact dermatitis is avoidance. It’s important to be able to identify the plant (knee height, with three green, pointed leaves, which turn red in the fall). Once identified, someone who is not allergic should remove it from areas close to your cottage or home.

Never burn the poison ivy plant, as the allergen can become airborne.

There is also a product available online called IvyBlock, which acts as a shield against poison ivy, poison oak and poison sumac by physically blocking contact with their resin. It will not treat the rash, but it is a preventative barrier.

If your son does get allergic contact dermatitis from exposure, treat it with cool water compresses followed by application of a prescription-strength hydrocortisone cream (see your doctor).

Benadryl can help with the itch but won’t improve the dermatitis.

Find Dr. Skotnicki-Grant’s clinic at baydermatologycentre.com

First published in Summer 2010 issue of Allergic Living magazine.
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