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Poison Ivy

What Is Poison Ivy?

The plants poison ivy, poison oak, and poison sumac all contain the same rash-causing substance. Called urushiol (yoo-ROO-shee-ol), this sticky, colorless, odorless oil is in the leaves of the plants.

What Are the Signs & Symptoms of Poison Ivy?

Urushiol is considered an allergen because it causes an allergic reaction. The reaction includes a rash with blisters, itching, and sometimes swelling. After a few days, the blisters may become crusty and start to flake off. The rash from poison ivy takes 1 to 2 weeks to heal.

this red, bumpy, itchy rash is a typical allergic reaction to poison ivy

About 60% to 80% of all people who touch urushiol have a reaction to it. The reaction can start within hours or as much as 5 days after contact.

How Is Poison Ivy Treated?

If your child comes into contact with poison ivy/oak/sumac:

  • Remove and wash any clothing that touched the plant.
  • Gently wash your child's skin and scrub under fingernails right away with soap and cool water.
  • Cut fingernails short to keep your child from breaking the skin when scratching. Broken skin can let bacteria in, causing infection.
  • Place cool compresses on the skin as needed.
  • For itching:
    • Add oatmeal to the bath.
    • Use calamine lotion on the skin (but not on the face or on the genitals).
    • If your doctor recommends it, give your child an over-the-counter oral antihistamine (Benadryl or a store brand).

When Should I Call the Doctor?

Call your doctor if your child has any kind of rash, especially with a fever. Most cases of poison ivy/oak/sumac can be managed with home treatment.

For more severe cases, doctors sometimes prescribe pills or creams with antihistamines or steroids (not the same type of steroids that bodybuilders use) to decrease itching and redness.

How Can We Prevent Poison Ivy?

Leaves of three, let them be! You've probably heard that little rhyme about poison ivy. Poison ivy can grow anywhere — from forests to backyards. And it's hard to identify: Not only can the green leaves of poison plants blend right in with other plants and brush, but there are several types of poison ivy, and each one can look different depending on the time of year.

It's also possible to get a rash from poison ivy without directly touching a plant. Urushiol can transfer from one person to another. Plus, kids can pick it up from anything that's been in contact with the oil, including pets. Urushiol can even travel through the air if someone burns the plants to clear brush.

The leaves of poison ivy plants release urushiol when they're bumped, torn, or brushed against. When the oil is released, the leaves may appear shiny or you may see black spots of ooil on them. Once released, urushiol can easily get on skin.

Here are some tips to help kids avoid getting a rash from poison ivy:

  • Teach them how to identify poison ivy, oak, and sumac, so they can steer clear of them (they should be especially careful of plants if the leaves look shiny).
  • Tell them to avoid areas where you know there's poison ivy.
  • Have them wear long sleeves and long pants when in areas where poison ivy might grow.
  • If your dog has been out exploring the woods, give him a bath to wash off any urushiol oil that may be on his coat.

If your kids are exposed to urushiol oil, have them try to wash it off their skin right away by taking a shower and using lots of soap.

Reviewed by: Steven Dowshen, MD
Date reviewed: February 2014