Poison ivy, oak, and sumac: How can I prevent a rash?

Ivy blockers may help

A study found that forestry workers who applied an ivy blocker on most days reported fewer rashes.

It’s an oil in these plants that causes the rash. By taking some precautions, you may be able to prevent the oil from getting on your skin. Here’s what you can do:

1. Protect your skin when outdoors. Poison ivy and oak grow in all states, except Alaska and Hawaii. Poison sumac is found in many states. When you’ll be in a wooded area or place known to have poisonous plants, you can:
   

   • Cover up with clothing. Wear long sleeves, pants, socks, and boots. If you’ll be working with plants, wear gloves.
   • Apply an ivy blocker to your skin. If you know you’ll be in an area with lots of underbrush, this can give you an extra layer of protection. It’s meant to be used along with long pants, gloves, and other clothing. You’ll find these non-prescription products online and in stores.
   You apply this product to skin that’s most likely to touch the plant’s oil, such as your hands, arms, and legs. To get the protection you need, apply an ivy blocker 15 minutes before going outdoors, and reapply as indicated on the package.

2. Wash everything after being outside. After being outdoors in a woody area or a place where poisonous plants may grow, you want to make sure you wash off any oil. To do this, put on a pair of disposable gloves and:

   • Machine-wash the clothing you wore. This includes hats and gloves. Wash everything in hot water and detergent as soon as you get home. The disposable gloves help you avoid getting oil on your skin. Be sure to wear the gloves while taking off your clothes and putting them in the wash machine.
   • Clean all tools and other equipment. Wipe these with rubbing alcohol or wash them with soap and lots of water. The oil can remain on surfaces for months or years until it’s washed off.
   • Bathe pets. The oil from these plants can stick to their fur.

3. Take a shower. You’ll want to take a warm shower and wash gently. Be sure to wash under your nails and rinse well.

Poison ivy, oak, and sumac: Where do these plants grow?

Poison ivy and poison oak grow in every U.S. state, except Alaska and Hawaii. See a map that shows you which poisonous plants grow in each U.S. state.

How a board-certified dermatologist can help

If you work or spend a lot of time outdoors and often get a rash from one of these plants, it can be helpful to see a board-certified dermatologist. A dermatologist can assess your situation and discuss what can help.

Image
Getty Images

References
Centers for Disease Control (CDC). “Poisonous plants and work.” Page lasted updated March 3, 2026. Last accessed April 23, 2026.

Kunin A. "Poison ivy, oak, and sumac: Don’t let them ruin your great outdoors.” In: The DERMAdoctor Skinstruction Manual. Simon & Schuster. United States, 2005: 202-8.

Margosian E. “More than poison ivy: Identification and treatment of hazardous plant exposure.” Dermatol World. 2018:28(6):36-42.

Marks JG, Fowler JF, et al. “Prevention of poison ivy and poison oak allergic contact dermatitis by quaternium-18 bentonite.” J Am Acad Dermatol. 1995;33:212-6.

Signore RJ, “Prevention of poison ivy dermatitis with oral homeopathic Rhus toxicodendron.” Dermatol Online J. 2017:15;23(1).

U.S. Food and Drug Administration. “Outsmarting poison ivy and other poisonous plants.” Page last updated June 9, 2021. Last accessed April 23, 2026.

Vaught CK, Mold JW. “Poison ivy: How effective are available treatments?” J Fam Pract. 2016;65(11):801-9.

Written by:
Paula Ludmann, MS

Reviewed by:
Jennifer Adams, MD, FAAD
Esteban Fernandez Faith, MD, FAAD
William Warren Kwan, MD, FAAD
Michael K. O'Donoghue, MD, FAAD
Desmond Shipp, MD, FAAD

Last updated: 4/28/26