Elena V. Simon, MD, is a medical resident at Milton Family Practice- – a certified medical home.

Summer in Vermont is a great time of year for outdoor activities with walking trails and dogs running through the woods.  Or, you might have finally found time to attack that overgrown area in the backyard.  Nobody wants to return home from an enjoyable day only to discover several days later a nuisance like poison ivy.

How to identify poison ivy?

A common saying is “leaves of three, beware of me,” since poison ivy often has clusters of three leaves.  It can grow as a vine or as a bush, and is often found along borders of woods or on river banks.  The poison ivy plant has green leaves in the summer, which turn red in the fall.  In the springtime, yellow, green or white flowers may grow on the plant, followed by white or green berries. Both poison ivy and its close relative poison sumac grow in Vermont and cause skin rash.

What kind of reaction is caused by poison ivy?

A rash called allergic contact dermatitis develops when our skin comes into contact with the oil from poison ivy.  This oil is called urushiol.  The oil is transferred to the skin by touching the poison ivy plant, by touching an object that has rubbed against poison ivy, or from particles of oil in the air landing on skin.  Once an object comes into contact with the poison ivy plant, the urushiol oil stays on it until properly washed off or all of it rubs off.  The oil can stay on an object as long as one year later!

How do I know if I have a poison ivy rash?

The typical poison ivy rash will look like red bumps in a line on the skin that touched the plant.  It usually starts with blisters that may weep, and, perhaps most famously, itches.  With time, the rash will dry out and become less irritated; it can take up to 30 days to resolve.

The rash from poison ivy is not contagious.  You will not spread the rash to other areas of your own body by scratching it… but you might worsen the rash by further irritating the skin or even causing a bacterial infection in addition to poison ivy.  If you notice new areas of rash popping up, these areas could have come into contact with the oil later than the original affected areas of skin.  Not everyone has the same sensitivity to poison ivy (about 15% of population does not develop rash), and your own body may react differently to poison ivy at different times.

I think I have a rash, but haven’t been the woods in days.  How can this be?

You might not remember coming into contact with poison ivy by the time you develop the itchy rash.  One reason is that poison ivy triggers a delayed hypersensitivity reaction: in other words, it can take several days for the body to respond to the urushiol irritant with a rash. Another reason could be that you actually did not touch the poison ivy plant.  Your clothes may have brushed against the plant and then you touched the oil on your clothing; or your pet ran through the plant and you touched the oil on your pet’s fur; or you were digging in the garden and later touched the tool which had the oil on it.

How to treat poison ivy rash…

  • Wash with soap and water immediately after exposure (the oil can cause a rash after five minutes to two hours of exposure on the skin).
  • Clean under your fingernails.
  • Wash all clothes, gardening tools, bedding, shoes and shoelaces, and pets that might have come in contact.  Rubbing alcohol can also be helpful in washing tools.
  • Calamine lotion, oatmeal baths, cool compresses and baking soda with water (3:1) can be helpful against itching.
  • See your doctor if a large area of your skin is involved.  Steroid pills might be used if more than 25% of your body or large areas of the face, hands and genitals are affected.

 …And tips for avoiding it in the first place!

  • If you know you are going to be working in a poison ivy area of woods, wear long sleeves and long pants and socks as well as gloves.
  • You might consider using a barrier cream for anticipated exposure, although research does not clearly suggest these creams prevent rash.  Always wash your skin, tools and clothing afterwards!
  • Never burn poison ivy plants because you or someone else could breathe it in and develop an internal reaction.

Elena V. Simon, MD, is a medical resident at Family Medicine Milton- – a certified medical home.

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