As you venture outdoors to enjoy summer, whether it’s to the lake, beach, garden or woods, it’s critical to know how to recognize poison ivy, which can trigger an allergic reaction ranging from mild to extremely severe.

Poison ivy comes in many forms. It can climb a tree as a vine or grow as a dense shrub along the ground. In shrub form it can have berries and small flowers, and to make matters worse, its appearance changes by season: in the spring its foliage is bright red and shiny, in the summer it’s green, and in the fall it’s reddish-orange.

In the spring, poison ivy is at its most attractive and also its most toxic. It contains urushiol, a toxic oil which binds with the lipids (fats) in your skin to cause the painful, itchy rash associated with the plant. The rash often oozes a golden liquid—which, by the way, is not contagious. The rash may occur from one to ten days after exposure, which accounts for the mistaken but widely held belief that it spreads from the oozing liquid.

The allergic reaction to poison ivy varies: some people have a horrific rash, while others have none. But someone’s reaction to the plant can change over time and with repeated exposure.

Only direct contact with the oil—either on the plant itself or on tools, laundry or a pet that just romped in the woods—can cause the rash. Those oils can remain toxic for more than a year.

Once you’re exposed to the oil, immediate washing is a must: dishwashing liquid that breaks down the oils works well, and pine tar soap or fel naptha soap works wonders. If you happen to have jewelweed on your property, you can crush the leaves and apply the juice to your skin. In a pinch, impatiens stems seem to work, too.

If it’s too late for that and you find yourself with blisters, baking soda can be a big help. Either put it in the bath (half a cup in a tub of water), or apply it right on the blisters as a paste (three teaspoons of baking soda per teaspoon of water, or double the amount for large areas). An oatmeal bath or paste also can be somewhat soothing.

Aloe vera gel works wonders for drying out the blisters and cooling the itch. Apis Mellifica helps with the heat and swelling associated with the rash, while another homeopathic product, Hyland’s Poison Ivy/Oak, relieves symptoms.

I have found that when I apply IvyBlock to my exposed skin before gardening, weeding or hiking, I often escape the rash. In a pinch I will apply T.N. Dickinson’s Witch Hazel, which also works as a barrier but needs to be reapplied every ten minutes.

All that being said, if blisters cover your body or become infected, as they often do due to scratching, it’s important that you seek medical attention. 

Dr. Minerva Santos is an integrative medicine physician with a practice at 48 Route 6 in Yorktown, NY. Contact her at 914.248.5556 or through MinervaSantosMD.com.