Got a blistery rash on your skin? If you've spent any time outdoors in the past few days, that rash could be caused by an allergic reaction to poison ivy, poison oak, or poison sumac. In all three cases, it isn't the plant itself that triggers the problem but rather a special oil called urushiol contained in these plants.

Recognizing Poison Ivy, Poison Oak, and Poison Sumac

Poison Ivy has a red stem with groupings of three red shiny leaves. It can be found within clusters of plants on the ground and it can also grow in vine form.

Poison Oak also has three leaves and often appears in a shrub-like shape. The leaves tend to resemble those of an oak tree, except the bottom side of them is usually a paler color than the top and can be covered in hair-like fuzz.

Poison Sumac is shrub-like, too, but with stems of seven to 13 leaves, which tend to "v" off in pairs from a center branch. It often has groups of drooping green berries.

If you see plants that resemble any of these descriptions, be sure to steer clear of them.

Poison Plant Reactions

If you do come into contact with the oil contained in any of these plants, you may experience streaks or patches of redness and swelling on your skin within a few hours to a day or two. Over the next few days, this rash will progress to an outbreak of red itchy blisters that will ooze if you scratch them. The blisters can last for a week or two before eventually drying up. 

Preventing the Allergy Rash

Your best bet to avoid this allergic reaction is to stay away from these plants whenever possible. Wear long sleeves and pants when hiking, fishing, or walking in areas where these plants may exist. Even if you've never had a reaction to any of these poisonous plants, you can be at risk for experiencing one with subsequent exposures.

Minimizing Exposure

If you believe you've come into contact with poison ivy, poison oak, or poison sumac, wash your hands, face, and body very thoroughly with soap and water to remove the oil. Make sure to get underneath your fingernails, where it can linger. You can also find products at your local drugstore that contain mineral oil and are specially formulated to remove the plants' oil from your skin.

Be sure to wash your clothes, shoes, gardening tools, and anything else that could have come into contact with this oil to prevent it from triggering a reaction later.

Also, bathe your pets frequently because although they won't react to these poisonous plants, they can spread the oil to people through their fur.

Treatment Matters

If despite your prevention efforts you find yourself coping with the itchy rash and blisters, try cool compresses on the blisters to soothe them or soak in special oatmeal bath products. Hydrocortisone lotion or calamine lotion may help with the itching. If this doesn't relieve your discomfort, your doctor may suggest taking an antihistamine. In very severe cases, steroids may also be necessary.



"Poison Ivy: What is Poison Ivy?" American Academy of Family Physicians. Dec. 2010. Web, 26 April 2011.

"Poison Ivy - Oak - Sumac rash." U.S. National Library of Medicine. National Institutes of Health (NIH), 1 Nov. 2009. Web. 18 April 2011.

"Tips to Remember: Allergic Skin Conditions." American Academy of Allergy, Asthma and Immunology. AAAAI, 2010. Web, 26 April 2011.