What Is Poison Ivy

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Everything You Need to Know About Poison Ivy

Poison ivy rash is caused by contact with poison ivy, a plant that grows almost everywhere in the United States. The sap of the poison ivy plant, also known as Toxicodendron radicans, contains an oil called urushiol. This is the irritant that causes an allergic reaction and rash.

You don’t even have to come in direct contact with the plant to have a reaction. The oil can linger on your gardening equipment, golf clubs, or even your shoes. Brushing against the plant — or anything that’s touched it — can result in skin irritation, pain, and itching.

Here’s how to spot the danger, and what you can do if poison ivy gets too close.

The allergic reaction caused by poison ivy is known as contact dermatitis. It happens when your skin comes into contact with an irritant, such as urushiol.

Poison ivy exposure can result in thin red lines on the skin when you’ve brushed against the edge of the leaves directly. If you touch pets that have the oil on their fur or touch clippings when emptying the mower bag, the rash can cover a larger area.

Classic symptoms that you’ve come into contact with poison ivy include:

• swelling
• redness
• itching
• painful blisters
• difficulty breathing, if you inhale smoke from burning poison ivy

The rash may begin appearing within 12 hours; it can take a few days to fully develop. Its severity depends on how much urushiol you get on your skin.

If you know you touched poison ivy leaves, you won’t need to see a doctor for an official diagnosis. If you do decide to visit your doctor, they can diagnose a poison ivy rash by looking at your skin. No other tests, such as a biopsy, will be needed.

Your doctor may order tests to help identify the cause of your symptoms if they’re not sure poison ivy caused the rash. Several common skin issues can cause red, itchy rashes.

For example, a common skin condition called psoriasis can be confused with a poison ivy rash. Psoriasis can cause a red rash with whitish-silver scales. This rash can be itchy, and it may even crack and bleed.

Psoriasis, unlike a poison ivy rash, will likely come back after it disappears. That’s because psoriasis is a chronic autoimmune disorder. Learn how to tell the difference between the two conditions so you can decide which you may be experiencing.

If you’ve gotten a rash despite your best efforts to avoid the plant, there are things you can do. You can usually treat the rash yourself at home. Poison ivy doesn’t have a cure, but even left untreated, it will eventually clear on its own within two to three weeks.

However, you should go to the emergency room for urgent medical care if:

• you have shortness of breath
• you have trouble swallowing
• the rash is on your face or genitals
• the areas with the rash are swelling
• the rash covers a large area of your body

Most cases of poison ivy don’t need to be treated by a doctor. Widespread poison ivy rashes may require treatment with a prescription corticosteroid. Rarely, you can also develop a bacterial infection at the rash site. If this happens, you may need a prescription antibiotic.

If you’ve come into contact with poison ivy, here’s what to do:

Wash your skin and clothes

Immediately wash any areas of your skin that might have touched the plant. This may help remove some of the oil and lessen the severity of your reaction.

Also, be sure to wash the clothes you were wearing, along with anything that may have touched the plant. Although the rash can’t spread, the oil that caused it can.

Take an antihistamine

Taking an over-the-counter (OTC) antihistamine can help relieve itching and allow you to sleep more comfortably.

Apply drying lotion

Apply calamine lotion or hydrocortisone cream topically to stop the itching.

Don’t scratch

Scratching the rash will only make things worse. While it may bring immediate comfort, scratching will only prolong symptoms. You may even develop an infection if you break the skin, causing itching to intensify.

Soothe your skin

Take frequent warm baths in water containing an oatmeal product or apply cool, wet compresses to help relieve the itch.

Some home remedies can help reduce irritation and itching while the rash is healing. These include:

Menthol cream

Organic compounds from peppermint have a cooling effect on irritated skin. You can buy OTC products with this ingredient, or you can make your own with peppermint essential oils.

Be sure to dilute the essential oil in a lotion or oil so it does not irritate the sensitive skin.

Several other essential oils, including calendula, chamomile, and eucalyptus may be helpful for reducing symptoms of poison ivy rash. Learn more about these oils and how to use them on irritated skin.

Aloe vera

The soothing burn treatment can also relieve itching and inflammation in skin affected by a poison ivy rash.

Colloidal oatmeal

Oatmeal baths are a popular home treatment for skin rashes and conditions. The finely ground oats can coat the skin and relieve itching temporarily.

Witch hazel

A liquid product of the Hamamelis virginiana plant, witch hazel may ease itching, swelling, and burning on irritated skin.

Apple cider vinegar

Apple cider vinegar is a popular alternative poison ivy treatment. Research isn’t clear why it helps, but anecdotal evidence suggests the vinegar solution helps dry up urushiol, which can speed healing.

No, poison ivy is not contagious. It cannot spread from person to person.

It can, however, be spread in a few other scenarios. For example, a pet that encounters poison ivy leaves can carry the urushiol oil in its fur. When you touch the animal, you may pick up the oil and develop a rash.

Clothing fibers can also spread poison ivy’s oil.

If you touch poison ivy with a pair of pants or shirt and do not wash it after contact is made, you could develop another rash if you touch the clothing. You can also spread the oil to another person, if they come into contact with clothes that have touched poison ivy.

A poison ivy rash cannot spread across your body either.

You may notice, however, that the rash develops over the course of several days. Poison ivy rashes can grow slowly, which may give the appearance of spreading. But a rash will only occur on areas of the skin that came into contact with the urushiol oil.

If you get a poison ivy rash after the initial exposure, consider everything you’ve touched that may carry the oil. Learn more about what these objects could be and what you can do to avoid sharing the oil with yourself or others again.

About 85 percent of Americans are allergic to poison ivy. These people will experience mild, but irritating, symptoms, such as a red rash, itching, and swelling. Of those who are allergic, about 10 to 15 percent will have a severe reaction. They may develop fluid-filled blisters that become infected.

Infants and toddlers can also develop a poison ivy rash. It may take several hours or days for the rash to fully develop. In severe cases, the child may also develop blisters.

The only way to know if you’re allergic to poison ivy is to touch it, which isn’t recommended. Instead, try learning what poison ivy looks like. This way you can work to avoid contact.

As with many other perennial plants, poison ivy changes with the seasons. The leaves of the poison ivy plant are green in the summer, but can turn red, orange, or yellow in the spring and fall.

The plant may flower with greenish-yellow blossoms and produce small, green berries that turn white in the fall.

Unfortunately, poison ivy can spread urushiol to skin in all seasons. Even in winter, when the leaves are gone, you can come into contact with the plant’s berries or aerial roots and pick up some of the sticky oil.

Older poison ivy shrubs or vines develop thin, hair-like roots above ground. These are the aerial roots, and they help identify the plant when the leaves have all fallen away for winter.

Poison ivy is native to every state except California, Alaska, and Hawaii and can be found in Central America, Mexico, and Canada as well. It’s been introduced to countries in Central America, Asia, and Europe and is found in Australia and New Zealand too. So, there’s a pretty good chance you’ll eventually cross paths with it.

Tips for identifying poison ivy

Learning how to identify poison ivy may help you avoid this highly irritating plant.

Poison ivy grows as a shrub in the northern and western United States.

The most commonly found type of poison ivy is known as western poison ivy. This type can grow to be anywhere from 6 to 30 inches tall. A second type, known as eastern poison ivy, grows as a trailing vine along the ground or clinging to trees in the East, Midwest, and South.

For both western and eastern poison ivy, the leaves are made up of three-pointed leaf clusters that have a glossy surface. This is where the old saying, “Leaves of three, let it be,” comes from. The edge of the leaflets can be toothed or smooth.

While certainly uncomfortable and irritating, a poison ivy rash doesn’t pose a serious risk to a pregnant woman or a developing baby.

Typical home remedies, including colloid oatmeal baths and topical anti-itch medicines are safe for pregnant women to use. However, it’s a good idea to talk with a doctor before taking any medications like Benadryl.

If you have any serious reactions during pregnancy, seek treatment right away and consult with your obstetrician as well.

Most Americans are allergic to poison ivy. More than 4 in 5 people will develop an itchy, red, swollen skin rash when they come into contact with poison ivy and its urushiol oil.

Of the people who are allergic to poison ivy, a smaller group are hypersensitive to the plant. These individuals are more likely to develop a severe reaction. About 10 to 15 percent of people with an allergy to poison ivy fall into this severe category.

A severe poison ivy allergy causes:

• severe swelling
• difficulty breathing
• blisters that become inflamed and infected

People with a severe poison ivy allergy should see their doctor as soon as a rash begins to develop. Treatments, including corticosteroids and antibiotics, may help reduce the severity of symptoms.

A poison ivy rash is bothersome. The itching and swelling can be irritating. Rarely, a poison ivy rash can be serious or fatal. When this happens, it’s often the result of complications caused by the reaction.

Complications of a poison ivy rash include:

Infection

A bacterial infection is a common complication of a poison ivy rash. Repeated scratching can cause microscopic breaks in the skin. Bacteria can make their way into the breaks, and an infection can develop. You will need antibiotics to treat this.

Poison ivy in the lungs

If you come into contact with poison ivy that is burning, you may inhale plant compounds. This can lead to irritation in the lungs, airways, and eyes.

Spreading

A poison ivy rash will only develop on skin that comes into contact with the plant’s oils. However, you can transfer the oil to other parts of your body if urushiol remains on your hands.

Also, the oil can remain on items like a pet’s fur, clothing, gardening utensils, and recreational equipment. If these items are not properly washed, you can pick up the oil again later, causing another rash.

Death

If you begin experiencing breathing or swallowing difficulties after coming into contact with poison ivy, seek treatment right away. This is an emergency situation that could become deadly without proper treatment.

An allergic reaction occurs when the oil comes in contact with your skin. Knowing what to look for is only part of the equation when it comes to avoiding the rash. The key is to prevent contact.

Prepare yourself before venturing into places where you might find the plant. This means covering your skin before gardening or doing other outdoor activities. You should also wear eye protection while mowing.

If you can’t cover your body completely, use an ivy blocking cream. There are several varieties that protect your skin from absorbing urushiol. They usually contain an ingredient called bentoquatam.

Apply it before going outdoors. Pack a supply of ivy blocking cream to take along with you if you’re hiking or camping.

Carefully clean items that have touched poison ivy to prevent exposure later. Gardening tools, sporting equipment, and camping supplies can all harbor urushiol.

A little prevention can go a long way. If you take precautions, you may never discover how uncomfortable the rash can be.

Last medically reviewed on April 17, 2019

What Is Poison Ivy?

A typical poison ivy rash is red, itchy, and swollen, and can also have hives or blisters.

Updated on November 6, 2022
Medically reviewed by

Leah Ansell, MD, is a board-certified dermatologist and assistant professor of dermatology at Columbia University.

Poison ivy is a poisonous plant that can cause a skin rash in people who come into contact with the leaves, stem, or roots. The medical name for this rash is contact dermatitis or rhus dermatitis. The rash is actually an allergic reaction to the urushiol oil produced by the toxic vine. This resin can be found not only in poison ivy, but also in poison oak and poison sumac plants.

Around 80% to 90% of people will develop this rash if they come into contact with the urushiol, says the Centers for Disease Control and Prevention (CDC). And it only takes a very smally amount of urushiol, less than one grain of table salt, to cause a reaction.

The hallmark poison ivy rash is red, itchy, and swollen, and can also have hives or blisters. You’ll likely know what it is when you see it, although your healthcare provider can tell you if the rash is caused by something else. Most cases of poison ivy rash go away on their own within a couple of weeks. Over-the-counter (OTC) creams and lotions can help ease the itch. In rare cases, poison ivy can cause more serious complications that may require medical treatment.

Here’s what to know about poison ivy rash, the plant that causes it, and how to treat it.

Signs and Symptoms of Poison Ivy Rash

A small percentage of people are immune to urushiol oil and wouldn’t know if they had a close encounter with a poison ivy plant. The other 80% to 90% will certainly know it, though perhaps not right away. Evidence that you’ve tangled with poison ivy can take hours or days to appear, depending on how sensitive you are and how much urushiol oil came into contact with your skin.

The main sign of poison ivy is a raised red rash where your skin has touched urushiol oil. The rash may show up in patches, lines, or streaks, which follow where the poison ivy came in contact with your skin. A poison ivy rash is usually also accompanied by swelling, hives, and bumps or blisters that can be either large or small.

A few days after they first appear, the blisters can crust and burst, letting loose a clear liquid. The rash may show up on different parts of the body at different times depending on how much oil came in contact with that particular area of the skin.

In more severe cases, poison-ivy rash can spread to your eyes, mouth, or genitals, and blisters may get infected with pus. Direct contact with the plant in any of these very sensitive areas can cause a rash, but you can also pick up the oils indirectly. For example, if the can or bottle you’re drinking out of has come into contact with poison ivy and you drink from the container, you can get urushiol in your mouth.

Smoke and soot from burning poison ivy can be dangerous. If you’ve inhaled urushiol smoke or soot, you may have trouble breathing. The CDC recommends getting medical help if your symptoms are severe or or the rash spreads to your face or genitals.

Symptoms in milder cases:

• Raised red rash
• Swelling
• Hives
• Bumps or blisters
• Itchiness

In more severe cases:

• Difficulty breathing
• Eyes swollen shut

Signs and symptoms of poison ivy should usually resolve within a few weeks. Anything longer than this probably requires a trip to your healthcare provider.

What Causes Poison Ivy Rash?

A poison ivy rash is caused by urushiol oil from a poison ivy plant coming into contact with skin. The skin quickly absorbs the oil, which then causes the hallmark rash. Contact with any part of the poison ivy plant—the roots, stem, or leaves—can cause this rash.

You can come into contact with this irritating resin either by touching a poison ivy plant directly, or indirectly by touching an object that has oil on it, such a gardening tool, a piece of clothing, a pair of shoes, or a pet’s fur. And if you inhale smoke from burning poison ivy, you can experience a severe reaction in your respiratory passages.

Urushiol oil doesn’t stay on the skin for very long, but the CDC says it can stay on objects for as long as five years. This means you can easily develop a rash after touching anything that has urushiol oil on it.

If the oil is still on your fingers, you can spread the rash to other parts of the body. However, you usually cannot get the rash by touching another person who has touched a poison ivy plant because the oil is quickly absorbed into the body. You also cannot get a rash from liquid out of a burst blister.

In some cases, you can inhale urushiol particles—or get them on your skin—from poison ivy plants that are burning nearby.

What Poison Ivy Rash Looks Like

Poison ivy rash can appear anywhere your skin has come into contact with the plant. The rash is red and can be irregularly shaped, or can appear as a line or streak. (Essentially, the rash will be an imprint of where you brushed against leaves or any other part of the plant.) It’s usually accompanied by swelling, hives, and bumps or blisters.

A few days after the rash first appears, the blisters will crust over and burst, releasing a clear liquid.

The rash may appear on different parts of the body at different times depending on whether that area touched a little or a lot of oil. In severe cases, the rash can spread to your eyes, mouth, or genitals. If this happens, contact your healthcare provider.

How To Identify Poison Ivy

Poison ivy grows either as a vine or as a shrub in most parts of the U.S. with the exception of Alaska, Hawaii, and certain areas along the West Coast, according to the U.S. Food and Drug Administration. The plant is known for the three glossy leaflets that grow on each leaf, a trait that gave rise to the famous warning phrase, “Leaves of three, let them be.”

The leaflets can be rounded or have multiple jagged edges, and they change color depending on the season. In the spring, the leaves are reddish. In the summer, they will be green. And in the fall they could be yellow, orange, or red. Sometimes the plants may also have black dots (this is urushiol). Poison ivy may sport berries—yellowish white, orange, red, or yellowish green depending on the season.

How Is Poison Ivy Rash Diagnosed?

Most cases of poison ivy are obvious just by looking at the rash and knowing or suspecting that you have come into contact with foliage. The rash will be red, swollen, and itchy and usually has hives and small or large bumps or blisters. The blisters usually last a couple of days before they burst, giving off a clear liquid.

Don’t be surprised if the rash looks different on various parts of your body at different times. This is normal and doesn’t necessarily mean the rash is getting worse.

A healthcare provider, particularly a dermatologist, can provide a more definitive diagnosis. The dermatologist can also help you rule out other causes.

Poison Ivy Treatment

There is no cure for poison ivy rash. It will usually go away on its own, even if you do nothing. But you’ll probably want to do something for the bothersome itching. Fortunately, there are treatments to relieve this and other symptoms.

If you think you may have come in contact with poison ivy, rinse your skin immediately. The CDC recommends using rubbing alcohol, poison plant washes, degreasing soap (like dishwashing soap), and lots of water. You may also want to scrub under your nails with a brush.

If you develop a rash, don’t scratch it. Instead, try one of many OTC products that are available to tame the itch, such as calamine lotion or hydrocortisone cream. The CDC also says oatmeal baths may help you feel less itchy. Oral antihistamine pills like Allegra (fexofenadine) or Benadryl (diphenhydramine) can also reduce itching and may help you sleep.

Contact your healthcare provider or go to the ER for any of the following reasons:

• You develop a temperature over 100 degrees
• The rash spreads to your genitals, eyes, or mouth
• You have trouble breathing
• Your tongue or throat starts swelling
• The rash covers more than a quarter of your body

And if your rash doesn’t show signs of abating after a week or 10 days, you’ll also want to contact your healthcare provider. Your healthcare provider may prescribe a stronger steroid ointment and, if you have signs of an infection (swelling, pain, pus around the rash, or a rash that is warm to the touch), an antibiotic.

Poison Ivy Rash Home Remedies

Simple home remedies can help ease itch from a poison ivy rash. Bathing in cool water can be a huge help, as can pressing a damp cloth (make sure it’s cool as well) on the itchy area for 15 or 30 minutes at various times throughout the day.

Avoid hot water, as that can worsen the rash. But a soothing oatmeal soak may do the trick. You can take a soak in a colloidal oatmeal bath (you can make your own or buy a product at the drug store). Some experts recommend easing blisters with a solution of one or two Dome-Boro tablets (available at most drug stores) dropped in a pint of water.

Poison Ivy Rash Medications

• Calamine lotion to relieve itch
• Hydrocortisone cream to relieve itch
• Oral antihistamines such as Benadryl to relieve itch
• Antibiotics to heal a bacterial infection around the rash
• Steroids in more severe cases to reduce swelling, redness, and itching

How Long Does Poison Ivy Rash Last?

It’s hard to know how long symptoms from poison ivy will last. It usually depends on how sensitive you are and how much oil got on your skin. If your skin is sensitive, symptoms may take longer to clear. A poison ivy rash that lasts one to three weeks is not unusual.

The first signs (red, swollen, itchy skin along with blisters) can develop hours or days after first contact with a poison ivy plant. A few days later, the blisters will get crusty and drop off.

A poison ivy rash may also show up on different parts of your body at different times depending on how much urushiol oil landed on certain areas. The skin usually absorbs the oil quickly, but it can linger on objects for years. If your rash doesn’t go away in a couple of weeks, contact your healthcare provider.

Is Poison Ivy Contagious?

You can’t get poison ivy from another person unless the person still has urushiol oil on their skin. This is unlikely, though, since skin absorbs the oil very quickly. You can also spread poison ivy on your own body if oil is still on your fingers or under your nails and you then touch other parts of your body. Washing and rinsing the skin after you’ve come into contact with poison ivy can stop the oil from spreading.

There is a danger of getting a poison ivy rash from dogs that have urushiol oil on their fur, or inanimate objects, where urushiol oil can hang on for years. These objects can include clothing, shoes, gloves, garden tools, your dog’s leash, and more. If you suspect an object has urushiol oil on it, clean it with rubbing alcohol or soapy water.

Be careful when touching your dog after it has been rollicking in the woods. If you suspect your dog has been in contact with poison ivy, you’ll want to wash your pup before checking for ticks. Wearing rubber gloves and goggles can protect you from droplets containing urushiol in case your dog shakes off the water. If you dry your dog with a towel, throw it in the washing machine and let your dog dry off fully before petting. You should also wash your dog’s leash, collar, and any other objects that may have urushiol on them.

How To Prevent Poison Ivy Rash From Spreading

If you’re going outdoors and think you might come into contact with poison ivy, learn how to identify the plant. If you see it while you’re out and about, steer clear. You may also want to teach any children you are with how to identify poison ivy as well.

If you know you’re going to be in an area that may have poison ivy, you may also want to use an OTC barrier cream as a buffer between urushiol oil and your skin. The active ingredient in these creams is called bentoquatum, which acts as a shield to protect the skin from urushiol.

You can also protect yourself by wearing long pants, long sleeves, gloves, and boots. If you’ve been in an area where you might have been exposed, wash the clothes you’ve worn separately in hot water with detergent, recommends the CDC.

When cleaning tools or other objects, use rubbing alcohol or soap and water. And don a pair of disposable gloves while you’re cleaning. This will help protect your hands from picking up any urushiol on the items you’re cleaning.

If urushiol oil from a plant does get on your skin, it could spread to other parts of your body if you touch the oil with your fingers and then touch another part of your body. If you think you’ve been exposed recently, rinse your skin with lukewarm soapy water or take a cool shower (not a bath, as that could spread the oil further). Brush vigorously under your nails.

How To Safely Get Rid of Poison Ivy Plants

If there are poison ivy plants in your yard, you can get rid of them yourself or hire a professional to do it for you. If doing it yourself, make sure you can accurately identify the plant first. When you’re ready to start the eradication, wear thick gloves, boots, long sleeves, and pants to make sure your skin doesn’t come into contact with the plant.

Poison ivy can be pulled out of the ground like a weed, but make sure you get the roots. Some people use an herbicide as well. And bear in mind that you can still get poison ivy rash from dead plants.

Most importantly, never burn poison ivy. Smoke from the burn will contain urushiol oil and is very harmful if inhaled. It can cause a severe allergic reaction that will make breathing difficult. And the smoke can affect anyone in the direct vicinity of the fire and even people who are far downwind, cautions the National Library of Medicine’s online service, MedlinePlus.

Once you’re done removing poison ivy, or at least done for the day, wash all your clothes and anything that may have come into contact with the poison ivy. And wash yourself—especially your hands—and scrub under your nails even if you’ve been wearing gloves.

A Quick Reminder

If you’ve had poison ivy rash once, there is a good chance you won’t forget it. The blisters and itchiness can be very uncomfortable. But there are things you can do to prevent getting the urushiol oil from poison ivy on your skin. Know how to identify poison ivy. Wear clothes that cover your skin. Use a barrier cream if you think you’ll be in an area that has poison ivy. Carefully remove and launder any clothing, and wash your skin with soapy water after spending time in places where you might find poison ivy growing.

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