Poison Ivy, Poison Oak and Poison Sumac
What is poison ivy?
Poison ivy is a common poisonous plant that causes an itchy skin rash. Other rash-inducing poisonous plants include poison oak and poison sumac. These plants produce an oily sap that contains urushiol (pronounced yer-OO-shee-all), which causes an irritating, itchy allergic reaction. When you touch the poisonous plant or an object that’s been in contact with the plant’s oil, you develop an itchy rash on that area of your skin. This rash is a form of allergic contact dermatitis.
How common is a poison ivy rash?
Up to 90% of people who come into contact with poison ivy oil develop an itchy rash. You don’t have to be exposed to much: 50 micrograms (μg) of urushiol — an amount smaller than a grain of salt — is enough to cause a reaction. You can become susceptible to a poison ivy rash at any time in your life, even if you never reacted to it in the past.
Who might get a poison ivy rash?
Nearly everyone who touches urushiol gets a poison ivy rash. You’re more likely to come into contact with a poisonous plant if you’re a:
- Camper or hiker.
- Farmer or gardener.
- Groundskeeper or landscaper.
- Forestry worker.
- Forest firefighter.
- House painter.
What do poisonous plants look like?
Poisonous plants grow everywhere in the United States except Hawaii and Alaska. Each type has a distinctive appearance.
What does poison ivy look like?
If you’re wondering how to identify poison ivy, look at its leaves. Each leaf of the poison ivy plant has three leaflets. A popular saying is, “leaves of three, let them be.” Poison ivy leaves turn reddish in the spring, green in the summer and yellow, orange or red in the fall.
Poison ivy grows as a shrub or a vine. A poison ivy vine is hairy and ropelike. Eastern U.S. poison ivy typically grows as a vine. Western U.S. poison ivy normally grows low to the ground as a shrub. Poison ivy does not have thorns. A poison ivy shrub may have white berries.
What does poison oak look like?
Poison oak leaves have three leaflets like poison ivy but with rounded tips. The undersides of the leaves are fuzzy and lighter in color than the top.
Poison oak typically grows as a shrub in the Eastern and Southern U.S. The shrub sometimes has white or yellow berries. Poison oak grows more commonly as a vine in the Western U.S.
What does poison sumac look like?
Each leaf of a poison sumac plant has clusters of seven to 13 smooth leaflets arranged in pairs. Poison sumac thrives in wet, swampy regions in the Northeast, Midwest and parts of the southeast U.S.
A full-grown poison sumac tree can get up to 20 feet tall. This tall tree has drooping clusters of pale yellow, cream-colored or green berries. Nonpoisonous sumacs have red, upright berries. Contact with nonpoisonous sumacs won’t cause an allergic rash.
Symptoms and Causes
What causes a poison ivy rash?
Poison ivy, poison oak and poison sumac produce urushiol oil. Almost everyone is allergic to it. The oil causes an allergic reaction when it touches your skin. The itchy rash that develops is a type of allergic contact dermatitis.
What are the symptoms of a poison ivy rash?
Poison ivy symptoms almost always include:
- An itchy skin rash.
- Redness and swelling.
Depending on your skin’s sensitivity, a rash may develop within a few hours or a few days after initial contact with urushiol oil. The intensity of the itching can vary, and some people may develop one or two small rashes while others develop rashes all over their bodies.
What does poison ivy rash look like?
A poison ivy rash on your skin usually looks like red, itchy bumps. Some people can develop black spots or streaks on their skin instead of the telltale red rash (this is rare). If you have black-spot poison-ivy dermatitis, you’ll have very little or no swelling or redness.
What do poison oak rash and poison sumac rash look like?
Poison oak rash and poison sumac rash look the same as poison ivy rash. This is because urushiol oil causes the same allergic reaction no matter which poisonous plant you touch.
What are the poison ivy rash stages?
No matter how long it takes for a rash to appear, it usually comes in stages and peaks within one to 14 days of exposure. However, symptoms can develop as long as 21 days after initial exposure to urushiol oil for those who’ve never been in contact with it before.
For most people, the stages of poison ivy rash include:
- Itching: Your skin will begin itching intensely where the rash will eventually appear.
- Rash: Soon after your skin begins to itch, the rash will appear. For most people, it’s an intense, blistering rash.
- Fluid-filled blisters: If you’ve developed blisters, they’ll break open and leak fluid.
- Crusting and itching: The blisters will crust over but will still be itchy.
Why is my poison ivy rash spreading?
It may look like your rash is spreading, but you’re actually developing new rashes on areas of skin that came into contact with urushiol oil. You might’ve touched a plant in some areas and not even realized it — for example, a backpack strap brushed against poisonous plants and touched your bare shoulder. Some rashes take longer to develop. The extent of the rash depends on your skin sensitivity and how much oil you touched.
Is poison ivy contagious?
You can’t get a poison ivy rash by touching another person’s rash. But you could develop a rash if you touch the oil on another person’s body or clothes. You can also come in contact with the oil by touching your pet’s fur or a contaminated item like a gardening tool or camping gear. The fluid from blisters doesn’t contain urushiol oil and isn’t contagious.
What are the complications of poison ivy exposure?
Some situations increase your risk of problems if you’re exposed to poison ivy, poison oak or poison sumac. These factors include:
- Inhaling smoke: When poisonous plants burn, they release urushiol into the air. You may develop a rash on your face from coming into contact with the smoke or on the lining of your nasal passages, mouth and throat from inhaling the smoke. Oil in the air also affects your lungs and can cause serious breathing problems.
- Scratching: It’s hard not to scratch this itchy rash. But you can get an infection if you scratch until your skin bleeds. Bacteria from under your fingernails can get inside any open wound.
Diagnosis and Tests
How is poison ivy diagnosed?
A healthcare provider will look at the rash, assess your symptoms and ask questions to determine if you could’ve encountered a poisonous plant. Other allergens and irritants besides poisonous plants can cause contact dermatitis or an itchy rash. If you haven’t been outdoors or in contact with plants, your provider will rule out other skin conditions or causes.
Management and Treatment
How do you get rid of poison ivy?
You can’t get rid of poison ivy in one day, but for the fastest relief, you should take the following steps:
- Rinse: Rinse your skin with soapy, lukewarm water as soon as possible. If you don’t wash off the urushiol oil, it can spread to other areas of your body and other people.
- Wash your clothing: Wash all of your clothes immediately. Urushiol oil can stick to clothing, and if you touch it again, it can cause another rash.
- Wash everything else: Wash anything that may have come into contact with the oil, including pets, gardening tools, camping gear or golf clubs.
- Avoid scratching: It’s difficult, but try not to scratch. Scratching can lead to an infection.
- Don’t touch the blisters: If your rash has blisters, leave them alone. Don’t peel off or try to remove the overlaying skin. This skin protects the wound and prevents infection.
- Prevent infection: With any itchy rash, the skin is vulnerable to infection due to abrasions from scratching. Keep skin clean and dry, and notify your healthcare provider if there are signs of infection.
How to treat poison ivy
Rashes from poisonous plants usually go away on their own within a week or two. In the meantime, poison ivy treatment includes over-the-counter (OTC) medications that can relieve the itchy rash:
- Anti-itch creams: Poison ivy creams include calamine lotion (Caladryl®) and hydrocortisone (Cortizone®). For blisters that start weeping or draining, you can use topical astringents made with aluminum acetate (Burow’s Solution® or Domeboro® astringent solution).
- Antihistamines: Antihistamines include medications such as diphenhydramine (Benadryl®).
Your healthcare provider may prescribe a poison ivy rash treatment if it becomes more severe or forms on the mucous membranes of your eyes, nose, mouth or genitals. They may recommend an oral steroid such as prednisone.
Your healthcare provider may also prescribe treatment for a secondary infection if this develops.
What else can I do at home to relieve the itch?
Home remedies for poison ivy include:
- Cold compresses: Try applying a cool compress to your itchy skin. Wet a clean washcloth with cold water and wring it out. Then, place the cool cloth onto the area that itches.
- Lukewarm baths: Taking a short, lukewarm bath with colloidal oatmeal (Aveeno®) can provide some relief from the itching. You can also try adding 1 cup of baking soda to your bath. Short, cool showers may also help.
How can I prevent a poison ivy rash?
The best way to avoid developing this itchy rash is by learning what poisonous plants look like so you can avoid them.
If you think you’ve come in contact with a poisonous plant, you can:
- Apply isopropyl (rubbing) alcohol to exposed body parts, gardening tools or other contaminated items to strip away the oil.
- Scrub under your fingernails with a brush.
- Use dishwashing soap and cool water to wash hands that have touched a poisonous plant.
- Wash clothes after being outdoors.
- Wear long sleeves, pants and gloves when doing yard work, gardening, farming or hiking.
- Wear rubber gloves while bathing pets that have been in contact with poisonous plants.
Outlook / Prognosis
How long does poison ivy last?
Poison ivy rashes cause mild (but annoying) symptoms that go away within a week or two. Rarely, a skin rash can last for longer than a month. Try not to scratch. Scratching can break open skin and cause an infection.
How long does poison oak last?
Poison oak and poison sumac rashes should go away within one to two weeks.
When should I call my healthcare provider?
Visit your healthcare provider if you have a poisonous plant rash and you experience:
- A rash covering more than a quarter of your body.
- A rash on the mucous membranes of your eyes, nose, mouth or genitals.
- Red streaks, fever or other signs of infection.
- Signs of anaphylaxis, including breathing difficulties, hives and swelling.
What questions should I ask my healthcare provider?
If you have a poisonous plant rash, you may want to ask your healthcare provider:
- Do I need any testing to confirm the rash is from a poisonous plant?
- How can I avoid getting this rash again?
- How can I keep my family members from getting this rash?
- What treatments can I use to reduce itching?
- How long will the rash last?
- Should I look out for signs of complications?
Frequently Asked Questions
What’s the difference between poison hemlock and other poisonous plants?
Poison hemlock is another poisonous plant that grows throughout the U.S. It differs from poison ivy, poison sumac and poison oak because you typically won’t get a rash if you touch it. Usually, poison hemlock is only poisonous if you ingest it. The plant is more toxic than poison ivy — it can be fatal if ingested.
A note from Cleveland Clinic
It’s hard not to scratch an itchy poison ivy rash. Fortunately, most rashes clear up with minimal treatment within a week. Ask your healthcare provider for suggestions to stop the itch. And remember, don’t scratch! You might temporarily feel better, but scratching can introduce bacteria into the skin and cause an infection.
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