November 28, 2015
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Poison Ivy, Oak, and Sumac (cont.)

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How do physicians diagnose poison ivy, oak, and sumac rashes?

The diagnosis of this rash is typically made by a health-care professional after obtaining a thorough history and performing a detailed exam of the skin. While some individuals will know and report exposure to poison ivy, oak, or sumac, others may not be aware of it and may not recall any exposure. The appearance of the characteristic rash is usually all that is needed to make the diagnosis. No blood tests or imaging studies are necessary.

What is the treatment for a poison ivy, oak, or sumac rash?

The initial treatment for someone who has recently been exposed to any of these plants includes rinsing the affected area with copious amounts of warm water within 20-30 minutes of exposure to remove the oily plant resin. The effectiveness of rinsing decreases with the passage of time, as the oily plant resin is quickly absorbed into the skin. Some authorities recommend rinsing with rubbing alcohol, commercially available poisonous plant washes, or degreasing soaps and detergents. It is also important to scrub under the fingernails to remove any remnants of the plant resin. In addition, thoroughly clean clothing or any objects that may have come into contact with these plants.

Picture of Poison Ivy Plant and Poison Ivy Skin Rash
Picture of poison ivy plant and poison ivy skin rash

If the characteristic rash develops, initial treatment consists of symptomatic care, as in most cases, the rash will improve on its own after one to three weeks. Self-care at home is usually all that is necessary. In the meantime, the following treatments may be useful to alleviate symptoms:

  • Apply cool compresses to the skin.
  • Use topical treatments to relieve itching, including calamine lotion, oatmeal baths, or aluminum acetate (Domeboro solution).
  • Oral antihistamines, such as diphenhydramine (Benadryl), can also help relieve itching.
  • For a more severe rash, a health-care professional may prescribe a high-potency steroid cream or an oral corticosteroid (such as prednisone).
  • Over-the-counter pain medication may be necessary for pain control.
  • Antibiotics may be prescribed if the rash becomes infected. Avoid scratching the rash to prevent the development of a bacterial infection.
  • Go to the nearest emergency department or call an ambulance if experiencing an anaphylactic reaction (severe allergic reaction) characterized by difficulty breathing, difficulty swallowing, facial swelling, or if one is exposed and have had a previous severe reaction to these plants. Also seek medical care if the rash involves the genitals or the face or if the rash shows signs of infection.
Medically Reviewed by a Doctor on 4/20/2015


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