Poison Ivy, Poison Oak, Poison Sumac
(Allergic Contact Dermatitis; ACD; Contact Dermatitis; Allergic Dermatitis)
by Michelle Badash, MS
Poison ivy, poison oak, and poison sumac are common plants. They can cause a rash in some people.
The rash is an allergic reaction to the oils of the plant. This oil is released if the plant is damaged or bruised. The reaction may develop after frequent contact with the plants.
The oil may pass right onto the skin. It may also pass onto items such as clothes, tools, or toys. The rash can occur after contact with these items. The oil on these items can cause a reaction years after first contact.
People may only develop a reaction after repeated contact with the plant. Contact with the oil is likely after:
The oils cause a very itchy and red rash. It appears within 24 to 72 hours of contact with the oil. The rash may look streaked and have oozing blisters.
Some people may have a severe reaction. Medical care should be sought for the following symptoms:
The doctor will look at the rash. It may be diagnosed based on appearance and possible contact.
The skin rash can cause discomfort. It will often pass on its own in 2 to 3 weeks.
Scratching can cause further damage to the skin. It can also increase the risk of infection. Treatment can help to ease itching. Steps may include:
If you have been exposed to poison ivy, oak, or sumac:
To avoid contact with poison ivy, oak, or sumac oils:
American Academy of Dermatology
US Food & Drug Administration
Public Health Agency of Canada
College of Family Physicians of Canada
Contact dermatitis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/contact-dermatitis. Updated November 29, 2018. Accessed October 30, 2019.
Outsmarting poison ivy and its cousins. US Food & Drug Administration website. Available at: https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm049342.htm. Updated June 6, 2017. Accessed October 30, 2019.
Poison ivy, oak, and sumac: Who gets a rash, and is it contagious? American Academy of dermatology website. Available at: https://www.aad.org/itchy-skin/poison-ivy-oak-sumac-who-gets-contagious. Accessed October 30, 2019.
Last reviewed October 2019 by EBSCO Medical Review Board Monica Zangwill, MD, MPH
Last Updated: 9/8/2020