The Rub on Poison Ivy

By Ashli N. Collins, M.D.

            Poison ivy, oak and sumac are many kids worst enemy in the spring, summer and fall.  As kids venture outdoors from the winter they head off into weeds to play or to climb trees.  We, as parents, are ecstatic that they are in the great outdoors exploring, playing, turning over rocks and chasing butterflies.  Besides bug bites and sunburns, another common problem for kids in these warm months is poison ivy.

It is estimated that a million people a year suffer from poison ivy.  For our pediatric population, the news is bad.  People between the ages of 5 and 20 have the most severe reactions.  An estimated 10% of people who contract poison ivy have a “very severe” reaction with significant swelling and itching.  Another frightening statistic is that 70-80% of the population will have an allergic reaction to the oil found in the sap from these plants.  Urushiol is a sticky clear, sometimes yellowish, odorless oil that will turn darker with exposure to oil.  Because the oils from the different plants are slightly different chemically, some people have a stronger reaction to one or another.  The oil from these plants can be carried on objects (garden utensils), clothing or animals that have come in contact with the plant.  As many kids find out, the plant can also release a toxic vapor when burned. Therefore, standing too close to a fire while it is burning these weeds can result in a rash or even injury to a person’s lungs or trachea.

Poison ivy, oak and sumac are part of the Rhus or Toxicodendron family and are found across theUnited States.  Poison ivy prefers to live east of theRocky Mountainswhereas poison oak prefers to live west of theRockies.  Poison sumac enjoys the boggy areas of the southern states although each of these plants have been found outside their normal habitat.  Interestingly,Hawaiiand northernAlaskaare free of these plants.  Poison ivy and oak typically have 3 leaves per stem (leaves three, leave be) but may actually have more.  Poison sumac often has 7-13 leaves per stem.  The urushiol oil can be found in the leaves, stems and roots of the plants.

Once a person has come in contact with a plant, a reaction to the oil usually occurs within 8 to 48 hours.  The oil itself penetrates the skin, however, within minutes.  Many recommend washing off your skin within 10 minutes of contact with the plant to try and prevent a reaction.

The first signs of the reaction are typically redness and swelling with gradually intensifying itching.  Blistering of the skin will often appear 24-72 hours after contact.  If it is not the child’s first exposure, however, this may occur quicker.  There are often linear streaks across exposed body parts as the plant has dragged across the area.  Many people believe the rash and blisters are contagious, but this is just a myth.  The fluid from the blisters and weepy rash cannot spread the outbreak.  Different levels of exposure on the skin to the urushiol oil lead to different areas breaking out at different times.  It is not uncommon for crops of blisters and redness to continue to develop up to two weeks after exposure.

I have for years told people that my sister could just walk by or even think about poison ivy and get it whereas I was “immune” to it.  Although some people don’t have a reaction the first time they are exposed, with multiple encounters they will develop a rash.  And as pointed out earlier, some people react to one or the other oils more strongly.  Come to find out after many days of weeding my yard, I am allergic to poison sumac.

If you know you or your child have been exposed to urushiol, try to clean all exposed areas with rubbing alcohol or cool water.  There are newer products out such as Zanfel or Ivy Cleanse Towlettes that will also help clean the areas.  Soap will sometimes just move the oil to another part of the body.  Wash all clothing, gear, or animals that may have come in contact with the plant.  Remember to get under fingernails or thoroughly cleanse your hair, as both will carry the oil for a while.

If you or your child develops the dreaded poison ivy rash, the main treatment is helping the intense itching.  The rash itself can last up to 14 days.  Antihistamines such as benadryl can help with itching but may make your child sleepy.  Calamine or topical cortisone can also be used for short periods to help control the inflammation.  Cool compresses can also offer some symptomatic relief.  Warm water often will make the itching more intense.  If the rash is severe, involves the mouth or eyes, or is causing wheezing or coughing, you should see your primary care physician.  Sometimes oral steroids are used for these cases.  If areas become open and infected, antibiotics either topically or orally may also be prescribed.

Many parents ask about preventing this reaction…avoidance is the main thing.  Unfortunately, many young children as well as most adults cannot pick out a poison ivy plant.  If you know your child is sensitive, make sure they wear long pants and a shirt with long sleeves when playing in wooden areas or hiking.  Ivy-Block can be applied ahead of time to help decrease the likelihood to the oil penetrating the skin.  Be careful and be safe, it’s a jungle out there!

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Ashli Colins, MD.  Dr. Collins is a pediatrician with Oldham County Pediatrics, PLLC.  They have offices in LaGrange and in Louisville near the Summit.  For more information call 502-225-6277 or


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