Poison Ivy, Oak, and Sumac: Plants and Rashes

Even when dried-up, their leaves and stems can cause a rash.
Even when dried-up, their leaves and stems can cause a rash.

Poison ivy, poison oak, and poison sumac are plants that can cause a rash if you come in contact with the urushiol oil found in them. Even when dried-up, their leaves and stems can cause a rash. Here are a few things that may help you recognize them:

  • Poison ivy: It can be a vine or shrub, and it can be found throughout most of the states except in Alaska and Hawaii. It grows in wooded areas, fields, on the roadside, and along riverbanks. It can also be found in urban areas, such as backyards or parks. Mostly, its leaves are arranged in a cluster of three leaflets (trifoliate).
  • Poison oak: It grows more often as a shrub, although it can grow like a vine. It is found in the western United States and British Columbia. It also has a leaf arrangement (trifoliate) similar to that of poison ivy and may sometimes look like a true oak.
  • Poison sumac: It can grow either as a shrub or small tree, and it is found in the eastern and southeastern United States. It grows preferably near watery or wet areas. Each stem of poison sumac contains 7-13 leaves arranged in pairs.

It is wise to research a bit about the presence of any of these plants in a wooded area where you have not been before but are planning to go there. This can help you take precautions (before leaving for there) such as covering your body completely or applying an ivy blocker (shield against the oil) on the exposed areas.

What does a poison ivy, oak, and sumac rash look like?

The urushiol oil present in the leaves, stems, and roots of poison ivy, oak, and sumac is the one that is responsible for the rash. Most people who touch any of these plants will experience the following:

  • The rash appears wherever you itch.
  • Most often, the rash is red and blistering.
  • The rash itches so intensely that it can wake you while asleep.
  • The blisters tend to burst and leak the fluid.
  • The rash usually appears within a few hours after contact with the plant if you tend to develop allergic reactions. If you have not experienced the rash earlier, it may appear after two to three weeks.

How do you treat poison ivy, oak, and sumac rash?

Once you have come in contact with poison ivy, oak, or sumac plants, the first thing that you should do is rinse the affected skin thoroughly with lukewarm or soapy water. Here is what you can do to treat the rash at home:

  • You can apply cool compresses to the skin.
  • You can use topical treatments to relieve itching such as oatmeal or baking soda bath, calamine lotion, and hydrocortisone cream.
  • Oral pills of antihistamines such as cetirizine, Benadryl (diphenhydramine), Zyrtec (cetirizine), or Allegra (fexofenadine) also help relieve itching.
  • Take care to not scratch because scratching can cause an infection.
  • Do not pick the blisters because it can make the blisters open and expose the underlying skin to the germs.
  • Wash your skin gently because scrubbing the skin makes the oil irritate the skin further.

If your rash does not show improvement in 7-10 days or becomes infected (filled with pus and painful on touch), you should consult a board-certified dermatologist who can prescribe medications for the same.

How long does a poison ivy, oak, and sumac rash last?

The rash from poison ivy, oak, and sumac can be extremely itchy until it clears completely. How long your rash will last depends on whether you’ve had a rash from one of these plants before. If you have

  • A history of rash from poison ivy, oak, or sumac, the rash lasts for 1-14 days before clearing up on its own.
  • Never had a rash from poison ivy, oak, or sumac, you can have a rash for 21 days or longer before it disappears.


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Health Solutions From Our Sponsors

The United States Centers for Disease Control and Prevention. Poisonous Plants. Available at: http://www.cdc.gov/niosh/topics/plants/

American Academy of Dermatology Association. Poison Ivy, Oak, and Sumac. Available at: https://www.aad.org/public/everyday-care/itchy-skin/poison-ivy