Poison Oak: Identification and Treatment

What's the Difference Between Poison Oak and Poison Ivy?

By Samantha Caveny
June 24, 2019
poison-oak-identify-treat

Poison oak can be a harmful plant if you touch it, as its urushiol oil will cause a nasty rash.

California State University Channel Islands

“Leaves of three, let it be!” “Hairy vine, no friend of mine!” Learn how to spot poison oak, tell the difference between poison oak and poison ivy, and treat a poison oak rash. 

What is the Difference Between Poison Oak and Poison Ivy?

Poison oak is a relative of poison ivy. There are many similarities:

  • Both plants contain the same toxic resin, urushiol in all parts of the plant (toxic to humans but harmless to animals). 
  • Both plants have three leaflets, white flowers in spring, and can grow as a vine or a shrub.
  • Leaflets can range in size from the length of your thumb to the length of your hand.
  • Middle leaflet has a notably longer stem than the two side leaflets, though more obvious in poison ivy than poison oak.
  • Depending on the season, leaf color can range from green to orange and even a dark purplish-red.

But they are indeed different plants. In North America, there are two species of poison oak: Atlantic (Eastern) and Pacific (Western). 

Poison ivy (left) vs. poison oak (right)
Poison ivy (left) vs. poison oak (right)

How to Identify Poison Oak

  • Atlantic poison oak is a low-growing, upright shrub. It can grow to be about 3 feet tall, sometimes giving it the appearance of a vine. Pacific poison oak can grow either as a shrub or a vine, causing it to be even more readily confused with poison ivy.
  • Leaf shape resembles an oak leaf (hence the name, poison oak), but it’s not a member of the oak family.
  • Leaflets are duller green than poison ivy and usually more distinctly lobed or toothed.
  • Leaflets have hairs on both sides, unlike poison ivy.
  • Poison oak tends to grow at elevations between sea level and 5,000 feet.
  • While the fruit of poison ivy is the color of pearls, poison oak fruit (called “drupes”) has a tan color.

At the end of the day, just remember: Leaves of three, let it be. In other words, if you see a plant with clusters of three leaves, don’t touch it!

poison-oak-fruit-identify.jpgpoison-oak-cluster_0.jpg
Left: Poison Oak can be red in the fall, and its berries are tan when mature. Right: Poison Oak leaflets showing coloration.

Poison Oak Symptoms

Symptoms of poison oak include itchy red rashes that can resemble burns, swelling, and even blistering.

Symptoms can take 24-48 hours or even up to a week to show up, particularly if its your first exposure! 

Poison oak, like poison ivy, contains urushiol. This oily substance is what causes a poison oak rash, and it can be almost impossible to avoid. Upon contact with your body, urushiol immediately forms a chemical bond to the skin and causes an almost unstoppable allergic reaction. Urushiol will stay on clothes, pets, or other materials for months, and its potency lasts. This means that you could even get poison oak without going anywhere near it. 

The urushiol resin can cause harsher reactions for those who have been exposed to it before. Sensitivity to urushiol might decrease if you do not come into contact with it until later in life. Only about 15 percent of people are resistant to urushiol, so don’t feel safe around poison oak unless you are absolutely sure you are resistant. You also may become sensitive with repeated exposure, so your resistance might be short-lived.

Danger: Smoke inhalation from burning poison oak can send you straight to the emergency room. Avoid burning this plant (and poison ivy)!

Poison Oak Treatment

Your best chance at avoiding a reaction is to treat poison oak within 10 minutes of contact.

Urushiol is not water-soluble! Use strong soaps (like dish soap) and wash with cold water to keep the oils from spreading. Cleanse the area of contact within the first ten minutes, then rinse off with cold water. As urushiol can remain active for years, you’ll want to wash any clothes, items, or furniture that may have come into contact with the invisible oily residue.

If you don’t catch the exposure immediately, treat the resulting itchy rash and blisters topically with calamine lotion, baking soda pastes, aloe vera, and a number of commercial products.  If you don’t mind mixing breakfast and skin care, one tried-and-true remedy for itchy skin is oatmeal.  Since poison oak rash is the same as the poison ivy rash, see more remedies on our poison ivy page. If poison oak is extremely serious, speak to your doctor about a prescription.

Of course, the best remedy is always prevention; study our photos so you can recognize poison oak.

Have you ever had a run-in with poison oak? Tell us about it in the comments below!

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Reader Comments

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Poison Ivy and Oak and what of Ground Elder?

Ground Elder is a very tricky plant, scary in a way, it looks like Poison Ivy or Oak but is not poisonous. It is a ground vine originating from Europe.

Any suggestions anyone?

I have a nice "healthy patch" of poison ivy growing amongst my periwinkle plant bed and just wondered, any suggestions on how to kill the stuff? I just look at it and it makes me itch....well not really but it seems to be taking over the ground cover which once was nice and beautiful in the spring. Not any more. Any suggestions would be helpful...

Natural, no herbicide remedy to kill poison oak/ivy

How To Get Rid Of Poison Ivy Plants With Vinegar, Salt and Dish Soap

You can make a powerful homemade herbicide using a gallon of white vinegar, a cup of table salt (not Epsom salt) and a tablespoonful of dish soap.

Apply this mixture in the same way you would apply a commercial herbicide or bleach, except you wouldn‘t have to wear a hazmat suit! (You will want to wear long sleeves, pants, and solid shoes or boots to prevent contact with poisonous plants.)

Remember, if you plan to plant anything in the place of the poison plants, your application of table salt to the soil may prove problematic. Table salt will leach the soil of its nutrients. The soil will need amendments or you can simply establish a raised bed garden over it.

Many people have had success with this; however, it can take quite a few applications. If you plan to till the soil after the poison ivy has died, be very careful. The roots (even dead ones) contain active urushiol for up to five years.

Poison oak treatment

I got into poison oak two times as a child. It is true that you become more susceptible. The last time I had it I was about 33. I had just left for a short vacation with my husband and Friends, but I was suffering. It started on my upper arm as a tiny blister. I put something (can't remember), on the small rash then wrapped it with an Ace bandage. In the morning my arm was extremely swollen. I thought I would have to go to the emergency room, but instead called my doctor at home. He said to take Benadryl internally as well as externally on the rash. This relieved the pain and itch but did not heal it. I suffered through the day and night, but the next day went into the cool pool. Instantly, the pain and itch disappeared. I could feel the poison leaving my bloodstream. Other places where the rash had sprung out immediately went down. All that was left was flattened patches where the rash had been. I do believe that hot water, such as hot shower exacerbates it. It feels good, as if you're scratching, and I tend to think it has the same effect. So for me, Coldwater, and possibly the chemicals in the swimming pool healed it.

Poison ivy and poison oak rash

When I was a kid I always got poison ivy really bad. My mom tried everything and nothing worked. My grandpa told my mom to make me a hot bath and put a cup of Purex bleach in it. Then I had to bathe in the water until it got cold. I'm now in my late 40's and to this day I have not had but 1 small patch. So if you go swimming in a pool and you have either poison ivy or poison oak the chlorine in the pool will help.

Remedies for poison oak & poison ivy

A local herbalist, who has passed on, used to make a salve of Spotted Jewelweed (Impatiens capensis) which was the greatest healing product ever for poison oak or poison ivy. My oldest son is quite skeptical of herbals but this one he has thanked me over and over again for giving him.

Unfortunately, I know of no one who makes it anymore or even has a recipe. I was so hoping your article would have the recipe. I was surprised that the plant was not even mentioned.

jewelweed and poison ivy/oak

I've heard that the stalks and leaves of jewelweed can be crushed and the "juice" rubbed on the skin for relief of poison ivy. Try it!

Poison Oak

My son decided to make a 'crown of thorns' from a poison oak stem a few years back. He wore it on his head all afternoon in the hot summer. My sister wore it on her head too. The next morning she woke up with a rash on her face and neck. My son woke up with his head swelled so much he couldn't get his glasses on. He was having difficulty breathing. After a visit to the ER and daily visits to the doctor for over a week, the swelling went down. It was life threatening. Please do not underestimate the power of poison oak.

I have found that you can treat the blisters from poison ivy, oak, and sumac with Listerine. The plain brown colored one. It works as an astringent and helps take the itch out and helps dry up the blisters. We use it for all bites and rashes.

Poison - whatever

I thank God that I've never had any reaction to either poison ivy, oak or anything else! My brothers used to get it and my mom would make them soak in the bathtub with something called Blue Boro. I'm not sure if it's still made or whoever made it, but back then it seemed to help them - along with being covered with Calamine lotion. I've also heard that Fel's Naptha soap and bleach have worked for some people... just sayin...

I first got poison ivy in my

I first got poison ivy in my 40s and needed steroids to recover. I always thought I was "immune". You can become sensitive to it anytime, so be careful.

urushiol rash cure that works for me

I recently discovered this treatment and it has worked for me the last three times I used it. Soon after I saw a rash developing from contact with poison ivy, I mixed some calcium hypochlorite powder with water to form a paste and coated the afflicted area. The rash almost immediately receded. Calcium hypochlorite powder is available in a small packet at pool/spa supply stores. It is also the active ingredient in liquid bleach. So (I haven't tried this) making a paste with bleach and some inert ingredient should work exactly the same. It out-gasses small amounts of chlorine which I suspect reacts with the urushiol molecule to render it harmless.

Some people get nightmares MUCH worse than rash...

A "buddy" delivered some trunk-wood to me, neglecting to mention he didn't use it himself because it had been covered in heavy poison-something (I believe sumac). On a nice warm day, I chainsawed it into blocks wearing shorts (never mind the chainsaw-safety issue there). For hours, the saw shredded the tiny remaining fragments of the poison-X, and sprayed urushiol chips on my shins. Two days later, a BAD rash erupted all over my shins - angry red and white stripes like I had been whipped, not little blisters. The third day, I woke up soaked in blood, my skin "smeared off" on the bedding, and went to ER stat. I'll save you the details of the next few weeks, but I lost ALL the skin on my legs while changing massive antibiotic wet bandages to avoid SERIOUS infections. The pain was orders of magnitude worse than the emergency abdominal surgery I had a decade before -- unimaginable searing-blowtorch-while-being-fed-to-a-lawnmower pain. Happily, I avoided the feared infections, but the skin on my shins will never look normal again having been functionally flayed alive. So, don't write off poison-X as an inconvenience -- some people react VIOLENTLY if exposed more than trivially.

Warning!

When burning brush or yard debris - please be aware that the smoke from poison oak or poison ivy, if breathed in, can cause serious lung irritation.

- Also, pets who have been playing outside can get urushiol on their fur. It won't affect the pet - but it can be transferred to you when you pet or rub the animal or they rub against you.

- The urushiol from dead poison ivy / oak plants and vines can remain potent for years.

- There is a good video on YouTube that many may find helpful - look for "How to never have a serious poison ivy rash again"

Burning poison ivy

I've heard that poison ivy smoke can cause you to choke and can be fatal.

Poison ivy or oak on equipment

Urushiol from poison ivy or oak will adhere to equipment as well. Years ago a buddy & I went rock climbing. Shirtless, we both slung coiled rope over our shoulders which unbeknownst to us had been previously in contact with PI or PO. Needless to say, we both had a nice striped rash across our chests, shoulders, and backs where the rope had rested. Don't forget to clean equipment as well after being in the woods (walking sticks, boots, etc).

Remedy

Tecnu!!!! Go to your local pharmacy and ask for Tecnu, works like a charm to wash it off if you think it’s gotten on you. I keep a bottle handy at my place and in my truck year round and it does work! Another tip I’ve found is to spray yourself with Cedarcide (it’s cedar oil) which keeps everything from ticks to spiders off you when you’re in the woods. Since cedar is another oil, it creates a barrier and prevents the ivy oil from absorbing into your skin and it’s a natural bug alternative to chemicals on your skin. Trust me, I’m highly allergic to the ivy and I live in bug-ville. Both items work.

Tecnu really works!

I've been a firm believer in Tecnu since stumbling upon it in a drugstore decades ago. I overnighted a bottle to my dad when he got into some poison ivy or oak. He had gone to his doctor and gotten a prescription cream to put on, but it wasn't helping. He performed an experiment, using the Tecnu on one side of his body and the prescription cream on the other. When he went back to the doctor, the Tecnu side was much improved and did not itch, while the prescription cream side still itched and had a bad rash. After showing the doctor his results, he switched to Tecnu exclusively and got rid of the rest of his rash. I keep a bottle next to my bathroom sink during the growing season and use it if I even think I might have come close to any poison ivy. It really does work.

Poison Oak treatment

I get poison oak and ivy but have found this to be an effective treatment if I miss a spot when washing up after exposure or didn't notice touching it.
Take a branch of manzanita (Arctostaphylos) (leave flowers berries and all). Cut it up so that it lays flat in a pan and cover it with water. Put it to simmer for half an hour. Let it cool and dab this liquid onto the rash several times a day until the rash is completely gone.
For me the itching goes away the first day and the rash is gone by the 2nd or 3rd day. Without this treatment the rash lasts 3 to 4 weeks.

Here's the deal, some people

Here's the deal, some people get a reaction to Poison Oak, some do not. I work on a trail crew in Northern California. Of the crew, 7 out of 8 of us get a reaction from the plant. We are in the woods every day and the 7 of us that get reactions (including myself) always have a small rash somewhere on our skin. Our bodies have not built an immunity after years of exposure. The best thing you can do is to not come in contact with the plant. If you do, think that it is like coming into contact with grease and how easily it can spread from your clothing to your skin. My most recent bad reaction was from a clean shirt that was in P.O. 2 months ago which I hesitantly thought was safe to wear. That's my 2 cents.

Poison Ivy & Poison Oak

When I was 12, both of my Grandfather's who were avid gardeners and outdoorsmen, told me that if I spent a lot of time in the woods I'd never have a reaction to poison ivy or poison oak because I'd build up an immunity to them.
They must have been right because I've spent a lot of time in the woods in a lot of different states since then, I've never had a reaction to either poison ivy or poison oak, and I'll be 65 later this month.

poison ivy

My mom grew up roaming in the hills of Tennessee and never had a reaction until she was over 60 years old. She came in contact with poison ivy while cleaning out a fence line around her house. Don't think you're immune to the stuff - allergic reactions could crop up at any time.

Poison Ivy

My mother, who was sorely afflicted with hay fever anyway, unwittingly ran through a patch of poison ivy when she was a teenager. She was on a track that had been cleared, several other kids ran the same track and had no adverse effects, my mother ended up in the hospital, with a tube in her airway to keep it from swelling completely shut. They said she must have breathed in some dust that had the urushiol in it. Her sensitivity to allergens (hay fever) just served to make it worse.

When I was younger never

When I was younger never bothered me. I fished and hunted all over Texas hiked in it up to my neck never got it a couple years back decades later got it 2 times all over was miserable. Went to the Dr all they want to do is give you an injection with steroids. The best secret Cheap winter green alcohol 70% (1) Bottle of campho phenique liquid (1) bottle of 100 hundred count generic aspirins. Remove a little of the Alcohol and add back to the bottle later> Crush up all the aspirins in to an almost powder like state pour into the Alcohol bottle shake a few times repeat with the campho phenique liquid pour it into the bottle as well shake a few more times. Get a clean cotton wash rag pour some on it on pat all around the infected areas keep doing over and over and in about 3 days it will be gone.

itch relief

I've never reacted to uresol, when I was a kid in boy scouts I'd set my tent right in the middle of poison ivy patches to keep the others from trying to get in on my dinner (I cooked, while they were eating foil burgers and hot dogs I'd be having fried chicken, mashed potatoes and gravy, etc.)
That said, my mom and now my girlfriend are both highly allergic to it and if they will wash with SOAP (not detergent) ie: Ivory or Fells and cool water right after exposure they won't get any reaction. DO NOT use warm/hot water as this will open pores and allow the oil to get in them and you'll wish you could peel your skin off. If you wait until the reaction has begun, rubbing a wet bar of soap on the rash and letting it dry will relieve the symptoms and dry the rash. This will also work as a preventative, just rub any exposed skin with the wet soap bar before going out, let it dry on your skin and it will form a barrier on the skin that can be easily washed off after you get back in from the woods.

Got it without going near it!

My husband has always been a heavy construction worker. One time, the crew was working in a creek bed to shore up some sliding areas below a bridge. After about a week, I broke out with poison oak, and it got so bad that I ended up in the emergency room completely covered in it, and with it starting to go inside of my eyes, mouth, and other body openings! It was awful. Turned out I had been exposed to it by my husband's work clothes when I did the laundry! Needless to say, I stay FAR AWAY from it now!

Poison Ivy

I got into poison Ivy while trimming small branches from a small tree eight days ago. I was using a small hand saw. I just did not see it, but where my wrists touched the bark, just passed the glove gauntlet is terrible. I did go after five days and got a steroid shot and prescription Triamcinolone ointment. I am now trying white vinegar and that is soothing as well. Be sure and wash all clothing very well as well as yourself in lukewarm water. It had been 15 years since I got a bad rash. I sure wish I had inspected the area better.

Poison Ivy blisters

Will the poison ivy urushiol spread if you break open the blisters to speed up the drying out? Someone once told me that this doesn't cause spreading. I was also told today that pouring bleach on the punctured blisters helps speed up the drying process.

can poison ivy spread?

Hello! We’re sorry to hear you are dealing with poison ivy. The blisters leaking will not spread poison ivy because the fluid in the blisters is not plant oil. If you want to try bleach to relieve the itch and speed healing, combine equal parts water and bleach and dip a cotton ball into the solution. Apply to the affected area. Good luck!

Response to Dadbo

When I was little, my brothers and I would occasionally run into a patch of poison oak while playing outside. My mother treated the area by using cotton balls soaked in hydrogen peroxide and scrubbing the blisters with them. Hurt like you wouldn't believe, but dried up the blisters and stopped the itching. I would not use bleach on your skin, especially on broken skin, like blisters. Bleach is a caustic chemical and could leave you with a nasty, possibly serious, chemical burn.

Poison Oak/Ivy Blisters

I am very allergic and have had it several times to the point of weeping itchy blisters that last for 2+ weeks. Nothing worked well but I found I could dry up the blisters with PORTLAND CEMENT! If you have ever worked with concrete you know how dry your hands get. Pure Portland cement seems to work well at drying up blisters from these cursed plants. Just put apply the dry powder directly to the weeping blister. It seems to help the itch some also, but nothing beats a steroid for curing it quickly. I was always given a 7 day treatment of Prednisol and it reversed the effects quickly. It also gives you an appetite. It would make cardboard taste good so you may gain weight!

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