An Overview of Poison Ivy

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Poison ivy is an itchy, blistering rash that occurs when one's skin comes in contact with the oil found on the leaves, stems, roots, and flowers of the poison ivy plant. A sticky chemical, urushiol oil is quickly absorbed by the skin. The rash that results is actually a form of allergic contact dermatitis called Rhus dermatitis. While it resolves on its own in a week or more, the discomfort you experience in that time can be intense.

You may easily encounter poison ivy (Toxicodendrom radicans), or eastern poison ivy, when gardening, landscaping, hiking, or just enjoying the outdoors.

how to treat poison ivy
 Verywell / Jessica Olah

Symptoms

Rhus dermatitis is characterized by small, red bumps that form in a straight line or streaks. Blisters, which are small bumps filled with fluid, may also form. Swelling of the surrounding skin may also occur.

Keep in mind that your body needs time to become sensitized to urushiol oil. Because of this, you may not develop a rash the first time your skin comes into contact with poison ivy. However, with your next exposure, you likely will (around 85 percent of people get a rash when exposed to urushiol oil).

Exposure to urushiol oil from poison sumac and poison oak causes the same red, itchy rash as poison ivy.

Causes

According to the American Academy of Dermatology, there are three ways a person can develop a poison ivy rash:

  • Direct contact: Touching any part of the poison ivy plant that contains the oil may cause a rash.
  • Indirect contact: Urushiol oil is sticky. So if urushiol oil is on your clothes or gardening tools and you touch it and then your skin, a rash can form.
  • Airborne contact: If you burn poison ivy, urushiol particles may be released into the air. If these particles fall onto your skin, you may develop a rash.

Poison Ivy Is Not Contagious

Even if you scratch your rash and then touch another person, they will not get the rash. The only way for someone to develop a poison ivy rash is to be exposed to the actual urushiol oil.

Diagnosis

Diagnosis of poison ivy is two-fold—there must be a history of exposure to poison ivy along with the presence of the characteristic rash.

If your primary care doctor is uncertain of the diagnosis, or if there is not a known poison ivy exposure, he may refer you to a doctor who specializes in skin conditions. A dermatologist can sort out your diagnosis and rule out conditions that may mimic poison ivy, like another form of contact dermatitis or nummular dermatitis.

Treatment

There are two steps to follow if you believe you have been exposed to poison ivy (the same applies to poison sumac and oak):

  1. Immediately rinse the exposed areas with soap and cool water.
  2. Put gloves on and, using warm, soapy water, thoroughly wash everything you had with you, including your clothes, shoes, tools, and sports equipment. If your dog was with you when exposed, be sure to wash its fur.

The key to these two steps is being quick. If you wait more than 10 minutes, the urushiol will likely stay on your skin and trigger the poison ivy rash.

In the end, you may not be able to stop the rash from penetrating your exposed skin. But removing urushiol oil from your clothes, skin and even under your fingernails as best as possible can help you avoid spreading the oil and its rash to other skin areas.

If the Poison Ivy Rash Develops

Since a poison ivy rash typically goes away on its own within one to three weeks, typical treatments focus on controlling your itching. These anti-itch strategies can be easily performed at home and are usually all that is needed until the rash resolves:

  • Apply a wet, cool compress to the affected area.
  • Apply calamine lotion or a topical steroid cream (e.g., hydrocortisone cream).
  • Take an antihistamine (e.g., Benadryl) by mouth; do not apply a topical anti-histamine to your skin, as this can worsen the itch.
  • Take short, lukewarm colloidal oatmeal baths to soothe your itch.

If your rash is not getting better after a week of taking the above simple measures, it's important to see your doctor. You may need a prescription steroid cream or an oral steroid, like prednisone.

In addition, if you think your rash may be infected, it's also important to see your doctor. Signs of a potential infection include:

  • Fever
  • Blisters that are oozing a thick, yellow substance (called pus)
  • Increased redness or swelling, warmth, and/or pain around the rash

When Your Rash Is an Emergency

If you are experiencing a serious allergic reaction, such as facial swelling, or trouble swallowing or breathing, or if your rash is severe, widespread, or affecting sensitive areas of your body, like your face or genitals, be sure to go to your emergency room right away.

Prevention

While not always possible, preventing a poison ivy rash from occurring in the first place is ideal.

Gain Knowledge

It's a good idea to review some pictures of poison ivy/sumac/oak so that you know what they look like. Here are some characteristics of poison ivy/oak/sumac that may help you identify the offending plants:

Poison Ivy

  • Grows around lakes and streams in the Midwest and the East
  • Woody, rope-like vine, a trailing shrub on the ground, or a free-standing shrub
  • Normally three leaflets (which led to the old saying, ''leaves of three, let it be")
  • Leaves are all on the same small stem coming off the larger main stem, but the middle leaflet has a longer stalk than the other two
  • No thorns along the stem
  • Leaves are green in the summer and red in the fall
  • Yellow or green flowers and white berries
  • Aerial roots may be visible on the stem

Poison Oak

  • Eastern United States (from New Jersey to Texas): grows as a low shrub
  • Western United States (along the Pacific coast): grows to 6-foot-tall clumps or vines up to 30 feet long
  • Oak-like leaves, usually in clusters of three
  • Clusters of yellow berries

Poison Sumac

  • Grows in boggy areas, especially in the Southeast
  • Rangy shrub up to 15 feet tall
  • Seven to 13 smooth-edged leaflets
  • Glossy pale yellow or cream-colored berries

Block Skin Contact

In addition to gaining knowledge, blocking skin contact from the urushiol oil is a useful preventive strategy. To do this, wear long pants and a shirt with long sleeves, boots, and gloves when you are most at risk for coming into contact with poison ivy, such as when gardening or hiking in wooded areas or around lakes.

You may also consider applying an ivy block barrier on your skin, such as IvyBlock (bentoquatam), which prevents the urushiol oil from absorbing into your skin.

Find the Source

If you have begun treatment for a poison ivy rash, it is important to figure out where you (or your child) got exposed (e.g., your backyard, at the playground, or on the way to school or work). This way you can prevent re-exposure and warn others, so they don't get exposed.

Getting Rid of the Source

Once you identify poison ivy, especially if it is in your backyard, you will want to get rid of it, unless it is a part of your yard that you and your loved ones can avoid.

Unfortunately, trying to get rid of poison ivy can be difficult and dangerous, since poison ivy plants often grow back, and you run the very big risk of getting exposed while trying to eradicate them.

Some options to consider when you need to get rid of poison ivy include:

  • Call a professional landscaper to remove the poison ivy plants, especially if you have a lot of poison ivy in your yard.
  • Spray the poison ivy plants with an herbicide, keeping in mind that they can also kill surrounding plants.
  • Manually remove the poison ivy plants, including the roots.
  • Repeat spraying or manually removing the poison ivy plants as they grow back.

If removing the poison ivy plants on your own, be sure to wear protection, and keep in mind that urushiol oil can remain on your clothing and gloves, etc., causing a rash if you later touch them.

It's best to wear old gloves and clothes you can trash so you aren't bringing the toxic oil into your house, washing machine, and clothes dryer. Also, be sure to properly dispose of the poison ivy plants, since even a dead poison ivy plant can trigger a reaction.

A Word From Verywell

No doubt, coping with a poison ivy rash can be frustrating. That said, be at ease knowing that in most cases, it can be treated with simple anti-itch remedies like over-the-counter hydrocortisone cream, calamine lotion, or an anti-histamine. Do your best to soothe your itching, and if you are worried, do not hesitate to give your doctor a call.

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Article Sources

  1. Poison Ivy, Poison Oak and Poison Sumac | Boston Children's Hospital. Childrenshospital.org. Published 2019.

  2. UpToDate. Uptodate.com. Published 2019.

  3. Outsmarting Poison Ivy and Other Poisonous Plants. U.S. Food and Drug Administration. Published 2019.

  4. Poison Ivy, Poison Oak and Poison Sumac. Poison.org. Published 2019.

  5. Usatine RP, Riojas M. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010;82(3):249-55.

  6. Bentoquatam Topical: MedlinePlus Drug Information. Medlineplus.gov. Published 2019.

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