Poison Oak

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Poison Oak  

                                                                                                                 10/5/09 new

Co-authored by Dr. Alai and Almira Yang, B.S.

Poison oak, also called Western Poison-oak or Pacific Poison-oak, is a cause of allergic contagious dermatitis (ACD).  Poison oak may appear as a dense shrub in open sunlight or as a woody vine under shadows. Similar to Poison Ivy, Poison Oak has three smaller leaflets on each leaf.  Poison Oak plants contain oil called urushiol, a toxic chemical in their leaves, stems, and roots. Many people develop an allergic reaction through direct or indirect contact with urushiol, or inhalation of urushiol smoke. The initial immune reaction begins once the poisonous substance is absorbed onto their skin or through mucous membranes like the nose or lips. Together with Poison Ivy, Poison Oak leads to ten percent of lost work time in the U.S. Forest Service. Hundreds of firefighters in California’s coastal ranges are so severely affected that they cannot work.

While about 15% of people may be immune to Poison Oak, this poisonous oil can cause serious allergic reactions in the majority of people. Typically, Poison Oak takes 12 to 72 hours to penetrate the skin. Once absorbed by the skin, Poison Oak can induce severe itching, redness, and swelling, following by small or large blisters on the skin of the person who contacts it. The delayed onset rash may appear on any part of the body after a short incubation period. However, the rash itself generally does not spread, and it is not contagious between individuals.

The sensitivity to Poison Oak tends to develop with repeat exposure and varies between individuals. Generally, sensitivity to Poison Oak tends to decline and sometimes disappear as people age. Children who have reacted often experience a decrease in their sensitivity by young adulthood.  Nonetheless, essentially anyone who has developed a prior sensitivity through exposure to Poison Oak may develop an allergic reaction.

Poison Oak’s resin, called urushiol, can remain active for a very long time. When an allergic reaction occurs after contacting poison oak, the first thing to do is to wash the skin thoroughly with warm soap and water, and launder any clothes that may be contaminated with Poison Oak. Some soothing remedies such as showering with cool water, applying over-the-counter anti-itching cream, oatmeal baths, or baking-soda mixture may help lessen the discomfort in mild cases. If the allergic reaction is severe, one should contact a physician or go to the emergency room, and some prescription medications including topical and oral steroids may be needed to reduce the swelling and itch.

DO’s

  • Learn to recognize and avoid contacting poison oak
  • Wear long pants, long sleeves, boots, and gloves to protect the skin
  • Apply an over-the-counter skin barrier product that contains bentoquatam to prevent Poison Oak from penetrating the skin
  • Remove plants if they grow near your home
  • Wash immediately after a suspected exposure

DON’Ts

  • Rub when the allergic reaction develops because it may lead to secondary bacterial skin infection
  • Touch objects that may be contaminated with Poison Oak
  • Burn poison oak to get rid of it
  • Touch plants even if they are dead because they may still contain urushiol (it can remain active for up to 5 years)


 


 

Poison Oak – Allergic Contagious Dermatitis

Poison oak (Toxicodendron diversilobum), also called Western Poison-oak or Pacific Poison-oak, is a cause of allergic contagious dermatitis (ACD). It is distributed from Baja California, Mexico north to British Columbia, Canada, and is ubiquitous in California west of the Sierra Nevada and the Mojave Desert. The appearance of poison-oak varies. The poison oak may appear as a dense shrub in open sunlight or as a woody vine under shadow. Similar to poison ivy, poison oak has three smaller leaflets on each leaf. The poison-oak plants contain oil called urushiol, a toxic chemical, in their leaves, stems, and roots. Through direct or indirect contacting with urushiol, or inhaling urushiol smoke, many people develop an allergic reaction once the poisonous substance is absorbed into their skin. Together with poison ivy, poison oak leads to ten percent of lost work time in the U.S. Forest Service. Hundreds of firefighters in California’s coastal ranges are so severely affected that they cannot work.

While about 15% people are immune to urushiol, this poisonous oil can cause serious allergic reactions in most people. Typically, urushiol takes 12 to 72 hours to penetrate the skin. Once absorbed by the skin, urushiol can induce severe itching, redness, and swelling, following by small or large blisters on the skin of the person who contacts it. The rash may appear on any part of the body in that there may be a delayed reaction. However, the rash does not spread, and it is not contagious.

The sensitivity to urushiol develops with repeat exposure and varies between individuals. Generally, sensitivity to urushiol tends to decline and sometimes disappear as people age. Children who have reacted often experience a decrease in their sensitivity by young adulthood. Nonetheless, 1 in 2 adults who have not developed sensitivity may develop an allergic reaction to poison oak.

Urushiol can remain active for a long time. When an allergic reaction occurs after contacting poison oak, the first thing to do is to wash the skin thoroughly with mildly warm water and soap, and launder any clothes that may be contaminated with urushiol. Some remedies such as showering with cool water, applying over-the-counter anti-itching cream, oatmeal baths, or baking-soda mixture may help soothe the discomfort in mild cases. If the allergic reaction is severe, one should contact a dermatologist or go to the emergency room, and some prescription medication may be needed to reduce the swelling and itch.

 

 

 

DO’s

  • Learn to recognize and avoid contacting poison oak
  • Wear long pants, long sleeves, boots, and gloves to protect the skin
  • Apply an over-the-counter skin barrier product that contains bentoquatam to prevent urushiol from penetrating the skin
  • Remove plants if they grow near your home
  • Wash immediately after a suspected exposure

DON’Ts

  • Rub when the allergic reaction develops because it may lead to secondary bacterial skin infection
  • Touch objects that may be contaminated with urushiol
  • Burn poison oak to get rid of it
  • Touch plants even if they are dead because they may still contain urushiol (it can remain active for up to 5 years)
    Call to Schedule an appointment at (949) 582-SKIN 
    Dr. Gary Cole and Dr. Nili Alai are Board-Certified Dermatologists.
    For more information, please call (949) 582-7699 or visit the practice website at
    www.lagunaskincenter.com.

     


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