“Leaves of three, let them be.”


Can poison ivy be passed on from person to person? I have read online that once you have broken out with it, it isn’t contagious to other people, but people still freak out when they hear that someone they know has poison ivy.


A poison ivy rash is an allergic skin reaction. The skin rash is caused by an oil in the poison ivy plant called urushiol. The oil easily transfers onto skin, clothing, toys (balls, frisbees, etc.), and pets when brushed against its leaves, stems, and berries. Preventing contact with plants that cause rashes begins with correctly identifying them in nature:

Poison ivy grows as a three- leafed green weed with a red stem at the center. It grows in vinelike form in all parts of the country except the Southwest. Poison sumac is a shrub, not a vine, and has seven to thirteen leaves arranged in pairs along a central stem. Not nearly as abundant as poison ivy, it grows primarily in the swampy areas of the Mississippi River region. Poison oak grows as a shrub, and it is seen primarily on the West Coast. All three plants produce similar skin reactions. These skin reactions are forms of contact dermatitis.


A red, bumpy, and very itchy rash develops, usually appearing in a linear pattern where the urushiol gets scratched into the skin within 12-72 hours after exposure. Blisters filled with clear fluid develop in more severe cases. These blisters can open and weep and lead to the concern about potential contagiousness from our reader. Dr. Trina Peduzzi (Pediatric Alliance — Allegheny) addressed this common question on The PediaBlog nearly two years ago:

Is my child’s rash contagious? How about the weeping fluid that’s coming from the rash?

Nope, your child is not contagious. It can seem like the rash could be contagious, especially if your child has a small rash one day and the next day a much larger area is affected, but this is due to our delayed-type response. But no one can “catch” poison ivy from your child’s rash. The only way you can get the rash is from touching the oil.

The fluid that can come from the blisters is also NOT contagious. It is serum from blood and does NOT contain the urushiol oil that caused the rash.

However, if your child’s clothes, toys, or dearest cuddly pet friend were also exposed to the poison ivy and if any oil remained on the surface, this COULD produce more rash in your child if she touches the item. Wash any potentially exposed items well to prevent any further exposure. Oil has been reported to last up to 5 (!) years on surfaces. And never burn the poison ivy plant — the oil can become aerosolized and cause very dangerous respiratory problems in people.


Read the rest of Dr. Peduzzi’s “Poison Ivy Q&A” here.


***Do you have a non-urgent, clinical or otherwise (but nothing personal!) question for your Pediatric Alliance doctor or provider? Send an email with your questions to palblog@pediatricalliance.com and we’ll do our best to answer them and post them on The PediaBlog. You don’t have to include your child’s name, but an idea of their age is helpful. Also, please include the name of the division you go to and your doctor’s or provider’s name.

Ask us anything! (But, please, no urgent or semi-urgent questions — we may not get to your question right away. If your child is sick, or you have acute concerns, please call our offices and speak with our triage staff.)


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