Poison Ivy

Poison Ivy

There are three native American plants that collectively may be called poison ivy: poison ivy, poison oak, & poison sumac.

These plants can cause an allergic reaction in nearly 85 percent of the population. To be allergic to poison ivy, you must first be "sensitized" to the oils. This means that next time there is contact with the plant, a rash may occur.

What Causes an Allergic Reaction?

The resin in the plants contains an oily substance called urushiol. Urushiol is easily transferred from the plants to other objects, including toys, garments, tools, and animals. This chemical can remain active for a year or longer. It is important to know that the oils can also be transferred from clothing, pets, and can be present in the smoke from a burning plant.

What are the Symptoms?

The following are the most common symptoms of poison ivy. However, each individual may experience symptoms differently. Symptoms may include:

  • A contact dermatitis rash characterized by bumps and blisters that itch
  • Swelling in the area of contact sometimes occurs
  • Blisters that eventually break open, ooze, and then crust over

The symptoms of poison ivy may resemble other skin conditions. Always consult your physician for a diagnosis.

Did You Know?
Scratching poison ivy blisters will not spread the rash. In addition, the poison ivy rash is not contagious—only urushiol (oil found in the sap of poison ivy) can cause a reaction.

Treatment for Poison Ivy/Poison Oak

Specific treatment for poison ivy/poison oak will be determined by your physician based on:

  • Your age, overall health, and medical history
  • The extent of the condition
  • Your tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the condition
  • Your opinion or preference

Making sure you avoid the poisonous plants is the best treatment.

It is important to teach your family members what the plants look like and not to touch them.

If contact with the plants has already occurred, you should remove the oils from the skin as soon as possible. Cleansing with an ordinary soap within six hours after the initial exposure has proven to be effective. Repeat the cleaning with the soap three times. There are also alcohol-based wipes that help remove the oils. Wash all clothes and shoes also, because the oils can remain on these.

If the blisters and rash are on the face, near the genitals, or all over the body, your physician should be notified. After a medical history and physical examination, your physician may prescribe a steroid cream, oral steroids, or steroid injections to help with the swelling and itching, depending upon the severity of the rash.

Is Poison Ivy/Poison Oak Contagious?

Poison ivy/poison oak cannot be spread from person to person by touching the blisters, or from the fluid inside the blisters. It can be spread, however, if the oils remain on the skin, clothes, or shoes. This is why washing your hands, clothes, and shoes as soon as possible is very important.

Preventing Poison Ivy/Poison Oak

  • Teach all family members to recognize the plants
  • Make sure you wear long pants and long sleeves when poison ivy or poison oak are in the vicinity
  • Wash all clothes and shoes immediately after you have been outside
  • Make sure you do not touch a pet that might have been in contact with a poisonous plant
  • Wash your hands thoroughly

The information in this article does not substitute for advice or information provided by your physician. In addition, please consult your physician for further information on specific medical conditions or symptoms that you may have.

This article is copied from the Yale Medical Group Health Information Website. Copyright ©2005-06 Yale University School of Medicine. Yale Medical Group, PO Box 9805, New Haven, CT 06536-0805. Revised: October 28, 2005.