Your Guide: Poison Ivy, Oak, & Sumac

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Poison Oak

  • 3 leaves (never 5)

  • Looks similar to poison ivy

  • No thorns

  • Leaf groups grow in an alternating pattern on the stem

  • Grows in dry, sandy areas as a vine or small shrub

  • Less common than poison ivy

  • Pacific poison oak is a big problem in California

  • Pacific poison oak grows as a ground vine, shrub, and climbing vine

  • Atlantic poison oak is not very common

Download Map of Poison Oak

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Poison Sumac

  • Grows as a small tree only in wet areas (often in mud)

  • Red stems

  • Oblong, tapered leaves

  • Wavy or smooth-edged leaves (not saw-toothed)

  • Parallel rows of upward growing leaves

  • May have pale yellow or green flowers in spring or summer, green berries in fall

  • Plant is rare

Download Map of Poison Sumac


Poison Ivy

  • 3 leaves (never 5)

  • No thorns

  • Leaves may be rounded or have points

  • Leaf groups grow in an alternating pattern on the stem (not directly across from each other)

  • Leaves may be red or green, even slightly yellow

  • Very common

  • Eastern poison ivy grows on the ground, climbs and sometimes as a shrub

  • Big problem in the Midwest through the east

  • Western poison ivy is only a ground vine

  • Western and eastern overlap in location so the plants are hard to tell apart

Download Map of Poison Ivy


What causes this rash?

A rash from any of these three plants is caused by an oil they produce called urishiol (you-roo-shee-all). When you come in contact with the plant, the oils are transferred to your skin or clothing. The oils often cause itching or blistering skin. Close to 85% of the population in the U.S. will develop a rash from coming in contact with these plants. Most of the time, a reaction from poison ivy, oak, or sumac can be treated with over the counter medications or home remedies.

When to seek medical treatment

  • You have trouble breathing or swallowing.

  • The rash covers most of your body.

  • You have many rashes or blisters.

  • You experience swelling, especially if an eyelid swells shut.

  • The rash develops anywhere on your face or genitals.

  • Much of your skin itches, or nothing seems to ease the itch.

If your rash is not improving after seven to 10 days, or you think your rash may be infected, your physician.

How can you get poison ivy, oak, or sumac?

  1. Direct contact. By touching poison ivy, poison oak, or poison sumac, you can get a rash. Every part of these plants — the leaves, stems, roots, and flowers — contains the oil urishiol.

  2. Indirect contact. Urishiol can stick to almost anything. If you touch a pet's fur, gardening tool, or sports equipment that has the oil on it, you can get a rash. Animals do not get this rash, however, they can transmit the oils causing the rash.

  3. Airborne contact. Burning these poisonous plants releases particles of urishiol into the air. These airborne particles can land on the skin or in your lungs. Be especially careful when burning brush. PREVENTION

How to protect your skin from poison ivy, oak, and sumac

  1. Become familiar with where the plant grows and what it looks like.

  2. If you know you will be in an area that has poisonous plant growth, use an ivy block barrier. This helps prevent the skin from absorbing the oil from the plant that causes the rash. These are available without a prescription and usually contain bentoquatam. Apply before going outdoors.

  3. Wear long pants, long sleeves, boots, and gloves. Even if you apply an ivy block, you need to cover your skin. Protecting direct contact with clothing is beneficial.

  4. Wash as soon as possible up to eight hours after coming in contact with poison ivy, oak, or sumac. Wash your skin in lukewarm soapy water or use a scrub meant to wash away the urishiol oils, such as Tecnu®, available over-the-counter at most drug stores.

  5. Wash thoroughly all clothing, tools, pets or other items that may have had contact with the poisonous plant. Urishiol can stick to many surfaces and will stay on those surfaces unless washed off.


To treat a rash from poison ivy, oak, or sumac and to help stop the itch, we recommend the following:

  1. We know it’s hard not to, but DO NOT SCRATCH! Scratching can cause infection. Your hands and nails carry lots of bacteria and germs so keep them away from your rashes.

  2. Leave your blisters alone. The blisters protect the underlying skin and once exposed this skin is a raw wound. By leaving the blisters alone you can prevent further infection of your skin.

  3. To ease the discomfort, take a short lukewarm bath with a colloidal oatmeal preparation or add one cup of baking soda to running water. You can also take a short cool shower and use a Tecnu® wash or scrub to help with the itching.

  4. Use a topical preparation like calamine or hydrocortisone cream to help with the itch. We also recommend products like Ivarest®, Ivy-dry®, or our own WYB Poison Ivy Itch Relief to help dry up with blisters and help calm the itching, (all found at CustomPlus Pharmacy.)

  5. Consider applying a cool compress. This can sometimes help calm the itchy skin

  6. You can wet a clean washcloth with cold water and wring out the excess then apply to the affected area.

  7. Lastly, an ORAL antihistamine might be a good option to help reduce itching. Do not apply a topical antihistamine, as doing so could worsen the rash and itch.

MYTH VS. FACT: You can get a rash from touching someone else that has a rash from poison ivy, oak, or sumac.

MYTH! It is NOT possible to get this rash from touching someone who has the rash. The skin absorbs the oil too quickly.

MYTH VS. FACT: The rash will spread if you get the fluid from the blisters on you or someone else.

MYTH! You CANNOT get a rash from getting the fluid from inside the blisters on your skin or on someone else.

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