Poison Oak, Ivy, and Sumac: A Guide

Medically Reviewed By Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
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Poison oak, ivy, and sumac are plants throughout the United States. The oils from these plants can cause an allergic reaction that presents as a rash. This article will tell you how to identify the poison oak, ivy, and sumac plants. It will also discuss the symptoms and appearance of the rash they can cause. Finally, it will talk about treatment for the rash and how to prevent it.

How do you identify poison oak, ivy, and sumac?

Image of plant behind a wire fence
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Poison oak, ivy, and sumac are plants that grow in almost every area of the U.S. The only areas where they do not typically appear are Alaska and certain parts of the desert in Nevada. Due to their prevalence, it is important to be able to identify the different plants so you can avoid them.

An oil called urushiol oil is on each of these types of plants. This oil is what causes the allergic reaction that can lead to an itchy and irritating rash.

Poison oak

Image of poison oak plant
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In the eastern and southern parts of the U.S., poison oak typically grows as a low shrub. In the Pacific coast areas, it generally grows in long vines or tall clumps.

The leaves of poison oak typically grow three to one stem. This is where the saying, “leaves of three, let it be” comes from.

Poison oak plants may also have green or yellow flowers, and clusters of berries that are either yellowish-green or white.

Poison ivy

Image of poison ivy plant
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You can find poison ivy throughout the U.S., except for in Hawaii, Alaska, and parts of the West Coast.

Each leaf has three glossy leaflets with either smooth or toothed edges. Eastern poison ivy typically grows in a hairy, rope-like vine. Western poison ivy is typically a low shrub that does not form a climbing vine.

Poison ivy plants may also have green or yellow flowers, or greenish-yellow, white, or amber berries.

Poison sumac

Image of poison sumac plant
Buddy Mays/Getty Images

Poison sumac tends to grow in the swamps or bogs of the Northeast, Midwest, and some parts of the Southeast.

It typically grows as a tall shrub or small tree. Each leaf has its own cluster of 7–13 leaflets with smooth edges arranged in pairs.

The leaves are orange in the spring, green in the summer, and either yellow, orange, or red in the fall. It may also have glossy pale yellow or cream-colored berries.

Poison oak, ivy, and sumac rash

If you come in contact with poison oak, ivy, or sumac, take the following steps as soon as possible:

  1. Immediately wash your skin with rubbing alcohol, poison plants wash, or dish soap.
  2. Rinse thoroughly with plenty of cool water.
  3. Be sure to wash under your nails.

The rash from poison oak, ivy, or sumac typically occurs within 4–48 hours of contact if you experienced a rash. If this is your first time developing a rash, it can take 2–3 weeks.

Symptoms that may appear after coming in contact with one of these plants include:

  • a reddish or discolored rash
  • bumps
  • red or discolored patches or streaking
  • blisters weeping
  • swollen areas
  • itchiness

Appearance

Typically, the first indication of a reaction to contact with a poisonous plant is your skin itching. The itching may be intense. Shortly after this, the itch appears. The rash typically:

Sometimes instead of a red or discolored rash, people will develop black spots or streaks. This generally looks like black lacquer spilled on your skin.

The severity of the rash can vary from person to person. Some people only develop one or two small rashes. While others may develop a rash all over.

Learn more about poison ivy rash and when to contact a doctor.

Poison oak, ivy, and sumac treatment

Generally, the rash that comes from poison oak, ivy, or sumac is treatable at home. You can typically treat it yourself if the rash is:

  • mild
  • on a small area of skin
  • from contact with poison oak, ivy, or sumac

You can treat the itchiness from the rash by:

  • bathing in short lukewarm baths
  • using calamine lotion or hydrocortisone cream
  • applying a cool compress to the affected area
  • taking antihistamine medication

It is important to remember not to scratch the rash. This can open the skin and lead to infection.

When to contact a doctor for a rash

If you notice any of the following symptoms, contact your doctor right away. They include a:

  • temperature higher than 100ºF (38°C)
  • tenderness on the rash, soft yellow scabs, or pus
  • sensation of worsening itchiness
  • rash spreading to your mouth, eyes, genital area, or more than a quarter of your body
  • rash that does not improve within a few weeks
  • widespread and severe rash
  • difficulty with breathing, since this requires contacting emergency services

Poison oak, ivy, and sumac prevention

Prevention is key when it comes to poison oak, ivy, and sumac. Learning what the plants look like can help you avoid them and the rash the oils on the plants can cause.

Other ways you can prevent this rash include the following:

  • Wash gardening tools regularly.
  • Wear the following clothing items if you think you may be near the plants:
    • long pants tucked into your boots
    • tops with long sleeves
    • gloves if you are working around the plants
  • Bathe your pets regularly, if they experience exposure to the plants.
  • Rinse off your skin with cool water and soap immediately after you come in contact with the plants.

Learn more about when to see a doctor for a rash.

FAQs

These are some more questions people asked about poison oak, ivy, and sumac.

How long does poison oak last on your body?

Typically, the rash will clear up within a week. However, if it lasts more than 7­–10 days, contact your doctor.

Is it okay to pop poison ivy blisters?

No, leave the blisters alone. Scratching or popping the blisters can lead to infection. If they open on their own, do not remove the skin. This can help to protect the raw wound underneath it.

Summary

Poison oak, ivy, and sumac are plants commonly in most areas of the U.S. The oils on these plants can cause an allergic reaction if you come in contact with them.

This reaction typically involves a highly itchy rash. If the rash is mild and not widespread, you can generally treat it at home with calamine lotion and antihistamines. It is important not to scratch, however, since this can lead to infection.

If the rash worsens, does not clear in 7–10 days, or becomes widespread, contact your doctor.

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Medical Reviewer: Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
Last Review Date: 2022 Aug 4
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Outsmarting poison ivy and other poisonous plants. (2021). https://www.fda.gov/consumers/consumer-updates/outsmarting-poison-ivy-and-other-poisonous-plants
  2. Poison ivy, oak, and sumac. (n.d.). https://www.aad.org/public/everyday-care/itchy-skin/poison-ivy
  3. The National Institute for Occupational Safety and Health (NIOSH). (2022). https://www.cdc.gov/niosh/index.htm