Home / Poisonings / Poison ivy

Poison ivy

If you have been one of those less than fortunate people who have experienced the poison ivy rash, then you know what a major nuisance it is.

Poison ivy, like poison oak and poison sumac, is a member of the Rhus genus of plants.

In the U.S., there are five different types of poison ivy, poison oak, and poison sumac.

Where does poison ivy grow?

  • Poison ivy is usually found east of the Rocky Mountains (see photo called Poison ivy and Poison ivy 2).
  • Poison oak may be found in the east or west but most common west of the Rocky Mountains (see photo called Poison oak).
  • Poison sumac grows in boggy areas of the southern US.

What causes the poison ivy rash?


  • The plant contains an oil, called urushiol, that causes an allergic reaction after the an exposure occurs.
  • The oil is in the leaves, vines, and roots. Any broken part of the plant can release this oil and pulling up the roots can release urushiol as well.

How do you get poison ivy?

  • From touching it’s leaves or roots or something that has touched it, like your clothes or your pet.
  • Only areas of the body that come into contact with the oil develop a rash.
  • The fluid from the blisters and the rash do not spread the rash.
  • Also, a reaction to poison ivy may occur after inhaling smoke from a burning poison ivy plant or leaves.

Is it contagious?

  • Poison ivy is not contagious.
  • Once you have the rash the oil has been absorbed and you probably can’t spread it to others or elsewhere on yourself.
  • If you get big blisters filled with liquid it is mostly water and will not spread the rash even if they break.

Are some people immune from poison ivy or more sensitive to it?

  • Some people do not have an allergic reaction after coming into contact with poison ivy but others do not have a reaction unless there has been a prior exposure(s).
  • Being sensitive to poison ivy does run in families and as people do get older, it does appear their allergic reactions are less severe.
  • It is estimated that up to 8 out of 10 people will develop a rash after exposure to poison ivy.
    So it is best to just avoid the stuff.

What does the rash of poison ivy look like?

  • After exposure to poison ivy, if a rash is to occur it usually takes 12 – 48 hours.
  • The rash, called rhus dermatitis, is usually red, raised, and often blistered at the central most areas.
  • Because people usually brush by the plants, the rash may have a “streaky,” linear, or line pattern (see photo called Poison ivy rash or Poison oak rash).
  • Blisters may open up but do not contain the poison ivy oil (see photo called Poison ivy rash 2).
  • The rash may continue to break out in new areas for 2 – 3 days after the initial rash because people unknowingly continue to contact it (e.g., unwashed clothes, garden tools).
  • The rash, blisters and itch normally disappear in 14 to 20 days without any treatment.

What can I do for my child if he/she have been exposed to poison ivy?

  • As soon as possible, preferably within 10 minutes, cleanse the skin first with rubbing alcohol followed by water (no soap yet).
  • Then take a regular shower with soap and warm water.
  • Clothes, shoes, tools, and anything else that may have been in contact with the urushiol should be wiped off with alcohol and water.
  • Be sure to wear gloves or otherwise cover your hands while doing this and then discard the hand covering.

What is the treatment for poison ivy to control itching?

  1. Cool compresses
  2. Oral antihistamines (e.g., Benadryl)
  3. Calamine, Aveeno (oatmeal bath), or baking soda to dry up blisters
  4. Topical corticosteroids (should be started as soon as possible to have the most benefit)
  5. Oral corticosteroids for more involve cases

How can poison ivy be prevented?

  1. Avoiding contact with the plant is the most important preventive measure.
  2. If you’ve already come in contact with poison ivy or any of the others, start washing anything that may have come into contact with it (soap, detergents and rubbing alcohol are all effective).
  3. Using a weedeater to remove poison ivy will result in spraying your legs with poison ivy. So wear long pants when weedeating.