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What is poison ivy?

  • “Poison ivy” is the term used to refer to contact dermatitis
  • Poison ivy is a rash that erupts after you have come into contact with poison ivy, oak or sumac.
  • This is 1 of the most common allergic reactions in the country.
  • A sap that comes from these plants causes an allergic response that triggers the rash on our skin. This sap is colorless, but turns brown to black after exposure to air.
  • You can come into contact with this sap from any cut or crushed area of the leaves or the plant.
  • Poison ivy, oak and sumac grow almost everywhere in the United States.
  • The oil of these plants can be spread by many things
    • Direct contact with the sap
    • Indirect contact with objects that have come into contact with the sap, such as shoes, clothes, sports equipment, garden utensils, or fur of animals
    • Airborne contact with the smoke of the burning bush

What does the plant look like?

  • Poison ivy: This plant usually grows as a shrub in this area, but may grow as a vine. It has 3 leaflets to form its leaves.
  • Poison oak: This plant is usually a shrub, but it can grow as a vine. It has 3 leaflets that form the leaves.
  • Poison sumac: This plant grows in standing water, such as peat bogs. Each leaf has 7 leaflets.


  • The reaction usually begins within 12 – 48 hours after exposure.
  • The rash can affect almost any part of the body.
  • Itching
  • Redness
  • Burning sensation
  • Swelling
  • Blisters
  • Some people can develop swelling in the throat, dizziness, and difficulty breathing if the reaction is severe.


  • You may have heard the saying “Leaflets three, let them be”. This refers to the way the leaves grow in poison ivy and oak.
  • If you know you have been exposed to one of the plants within the previous 6 hours, you may:
    • Remove all your clothes and shoes that touched the plant. Wash them as you are able.
    • Wash your skin with soap and water
    • Apply rubbing alcohol the parts of the skin that are affected.
    • Rinse with water


  • Make sure you wash all clothes and shoes with hot water and a strong soap.
  • Bathe any pets that have come into contact with the plants.
  • Keep your hands away from your eyes, mouth and face.
  • Do not scratch or rub the rash.
  • Take an over the counter antihistamine such as Claritin or Benedryl as directed on the label.
  • Apply any of the following:
    • Calamine lotion
    • Zinc oxide ointment
    • Paste made with baking soda; 3 teaspoons baking soda mixed with 1 teaspoon water
  • Take a lukewarm bath. You may use an over the counter preparation such as Aveeno colloidal oatmeal to the water.
  • If there is no relief with these measures, please see a provider.


  • Scratching poison ivy blisters will spread the rash.
    • False: The fluid in the blisters will not spread the rash. The rash is spread by the sap in the plant.
  • Poison ivy is catching.
    • False: The rash is an allergic reaction to the sap in the plant.
  • Dead poison ivy plants are no longer toxic.
    • False: The sap in the plants can remain active for up to several years.
  • Rubbing weeds on the skin will help.
    • False: There is no substance in the weeds that will relieve the symptoms of poison ivy.
  • One way to protect against poison ivy is to keep yourself covered.
    • True: However, you need to wash your clothes and shoes after they have been exposed to the sap. Also, any uncovered areas are still vulnerable to the sap.

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Last Updated 8/15/18

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