Poison Ivy, Poison Oak, Poison Sumac

(Allergic Contact Dermatitis; ACD; Contact Dermatitis; Allergic Dermatitis)


Poison ivy, poison oak, and poison sumac are plants that cause a rash in those allergic to them. This rash is caused by a chemical in the sap. About 50%-70% of people are sensitized to this chemical and are, therefore, allergic. Virtually everyone will eventually become sensitized if repeatedly exposed.
Poison Ivy Rash
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The allergic reactions to poison ivy, oak, and sumac occur when sensitized people come in contact with urushiol oil. This oil is found in the roots, stems, leaves, and fruit of the plant. This oil is released if the plant is damaged or bruised.If not washed, oil from these plants may stay potent for years on clothing, tools, toys, and other items, especially in dry conditions.

Risk Factors

Sensitized people are at risk if they:
  • Work or play in wooded areas during the spring, summer, and fall
  • Touch pets or animals that have come in contact with these plants
  • Handle clothes or objects that have come in contact with these plants
  • Are exposed to the smoke of these plants if they are burned


The main symptom of poison oak, ivy, or sumac is an intensely itchy, red rash. The rash appears within 24-72 hours of exposure to the oil. The rash often appears streaked and may develop into oozing blisters. The oozing material will not sensitize others.The skin rash may cause discomfort. It is not serious, though, and usually resolves on its own in 1-2 weeks. However, you should contact a doctor right away if you are highly sensitive or have the following symptoms:
  • Swelling of the face or throat
  • Rash on the genitals
  • Swelling or rash that covers more than one–third of your body
  • Rapidly spreading rash
  • Signs of a bacterial infection, such as pain, increased redness, fever, or pus

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