Poison ivy is native to North America and grows in every one of the lower 48 states except California. It grows mainly in clusters on the edges of woodland, where there is plenty of sunlight for it to grow. It is characterized by clusters of three leaflets, each growing on its own stem, connected to a main vine, hence the popular phrase “leaves of three, let them be.”
Poison ivy sap is found in nearly every part of the plant and contains an oil called urushiol. If any of this sticky oil comes in contact with the skin it can cause a blistering skin rash that is red, bumpy, and itchy. You can develop a reaction to urushiol from direct contact, touching contaminated objects (such as shoes or clothing), and even breathing in smoke from burning poison ivy – which can severely harm the lungs. The rash does not spread by fluid from the blisters. Therefore, once a person has washed the oil off the skin, the rash does not spread from person to person. However, the plant oils can remain active on surfaces and can cause allergic reactions even years later. Therefore it is necessary that all clothing, shoes, pets, gardening tools, and other surfaces are cleaned well. According to the U.S. Forest Service, 70 to 85 percent of people exposed to urushiol oil in poison ivy (and its cousins, poison oak and poison sumac) will experience an allergic reaction. Unlike other allergies that people may outgrow, sensitivity to this oil gets worse with each additional exposure.
Symptoms of Poison Ivy
- Extreme itching
- Red, streaky, patchy rash where the plant touched the skin
- Red bumps, which may form large, weeping blisters
A rash can appear within just hours or days after contact with the plant. The reaction can vary from mild to severe. In rare cases, the person with the rash needs to be treated in the hospital. The worst symptoms are often seen during days 4 to 7 after coming in contact with the plant. The rash may last for 1 to 3 weeks.
First Aid for Poison Ivy
- Wash skin thoroughly with soap and warm water, or with isopropyl alcohol. Because the plant oil enters the skin quickly, try to wash it off within 30 minutes.
- Scrub under the fingernails with a brush to prevent the plant oil from spreading to other parts of the body.
- Wash clothing and shoes with soap and hot water.
- Immediately bathe animals to remove oils from their fur.
- Body heat and sweating can aggravate the itching. Stay cool and apply cool compresses to the skin.
- Calamine lotion and hydrocortisone cream can be applied to the skin to reduce blistering and itching.
- Bathing in lukewarm water with an oatmeal bath product may help soothe itchy skin. Aluminum acetate (Domeboro solution) soaks can help to dry the rash and reduce itching.
- Taking oral antihistamines may be helpful.
- In severe cases, especially for a rash around the face or genitals, the health care provider may prescribe steroids, either by mouth or as an injection.
- Wash tools and other objects with a dilute bleach solution or rubbing alcohol.
When to Contact a Doctor about Poison Ivy
Get emergency medical treatment right away if:
- The person is suffering from a severe allergic reaction, such as swelling or difficulty breathing, or has had a severe reaction in the past.
- The person has been exposed to the smoke of burning poison ivy, oak or sumac.
Call your provider if:
- Itching is severe and cannot be controlled.
- The rash affects the face, lips, eyes, or genitals.
- The rash shows signs of infection, such as pus, yellow fluid leaking from blisters, odor, or increased tenderness.
- If fever develops, or if the rash persists from more than two weeks and begins to spread over more parts of the body.
Prevention of Poison Ivy
- Wear long sleeves, long pants, and socks when walking in areas where these plants may grow.
- Apply skin products such as Ivy Block lotion (an over-the counter barrier cream containg bentoquatam, which will prevent urushiol from affecting the skin) beforehand to reduce the risk of a rash.
- Learn to identify the poison ivy (and oak and sumac). Teach children to identify them as soon as they are able to learn about the plants. It will help you avoid the plants when you go outdoors to areas where you’d be highly exposed.
- Remove these plants if they grow near your home (but never burn them).
- Be aware of plant resins carried by pets.
- Thoroughly wash skin, clothing and other items as soon as possible after you’ve come in contact with the plant.