Q. My son suffers with rashes to poison ivy at the cottage. Is this an allergy?
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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