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Poison Ivy, Oak, and Sumac Rash

What is poison ivy, oak, and sumac rash?

Poison ivy, poison oak, and poison sumac are types of American plants. They each grow in different parts of the country. The plants cause allergic contact dermatitis in most people who touch them. The rash is caused by the body’s reaction to an oil in the plants called urushiol.

The first time you touch one of the plants, you may not get a rash. This is because your body’s allergic response is not yet sensitive to it. The next time you touch one of the plants, your body may react within 24 to 72 hours. The rash can’t spread from one person to another. But plant oils on skin and clothes can pass from one person to another and cause a rash.

What causes poison ivy, oak, and sumac rash?

The plants make an oil called urushiol. Urushiol gets on your skin if you touch the plants. And it’s easily spread from the plants to other objects. These include garden tools, clothing, toys, and pet fur. You can also inhale it from smoke if the plants are burned. Urushiol can stay active on any surface for a year or more and still cause skin rash. Because the rash doesn’t show up right away, you can spread the oils around your body without knowing it.

Poison ivy, oak, and sumac rash is not contagious. It can’t be spread from person to person by touching the blisters, or from the fluid inside the blisters. But oil that remains on skin, clothes, or shoes can be spread to another person and cause a rash.

Who is at risk for poison ivy, oak, and sumac rash?

You are more at risk for the allergic rash if you:

  • Go outdoors in an area where poison ivy, oak, or sumac grow

  • Don’t know how to identify and stay away from the plants

  • Touch clothing or objects of someone with the rash

  • Touch a pet who has been outside in contact with the plants

  • Work in job where you are around these plants. This includes farming, forestry, and firefighting.

What are the symptoms of poison ivy, oak, and sumac rash?

Symptoms can occur a bit differently in each person. The symptoms most often include a red, bumpy, itchy rash with fluid-filled blisters. The blisters break open, ooze fluid, and then crust over. The area of skin may also be swollen. Swelling can mean the allergic reaction is more severe.

The symptoms of poison ivy, oak, and sumac rash can be like other health conditions. Other plants and chemicals can cause a similar rash. Make sure to see your healthcare provider for a diagnosis.

How is poison ivy, oak, and sumac rash diagnosed?

Your healthcare provider will ask about your symptoms and health history. He or she will give you a physical exam. The physical exam will include looking closely at your skin.

How is poison ivy, oak, and sumac rash treated?

Treatment will depend on your symptoms, your age, and your general health. It will also depend on how severe the condition is.

Treatment is done to reduce itching. Itching can be treated with any of these:

  • Calamine lotion

  • Cortisone cream

  • Baths with baking soda or colloidal oatmeal

  • Steroid medicine by mouth or shot

Your doctor may also prescribe antihistamine medicine. This medicine won’t relieve itching. But it may help you sleep better and let you ignore the itch. Check with your provider if you have questions or concerns about taking an antihistamine. 

In some cases, you may need urgent treatment if you have a severe reaction and swelling.

Talk with your healthcare providers about the risks, benefits, and possible side effects of all medicines.

What are possible complications of poison ivy, oak, and sumac rash?

In some people, a severe reaction can occur. This causes swelling or trouble with breathing or swallowing. This is a medical emergency and needs treatment right away.

Infection is another possible complication. The areas can also become infected from scratching. Your healthcare provider may prescribe an antibiotic medicine to take by mouth.

Can poison ivy, oak, and sumac rash be prevented?

To help prevent poison ivy, oak, and sumac rash:

  • Find out which of these plants grow in your area.

  • Learn what they look like. Teach all family members what the plants look like.

  • Stay away from the plants when outdoors.

When you go outdoors:

  • Wear long pants and long sleeves when in the woods or yard.

  • Wash all clothes and shoes right away after being outside.

  • Don’t touch a pet that may have been in contact with one of the plants. Use gloves to wash your pet’s fur, if possible. Your pets can pass the oil on to you.

  • Wash your hands well, including under your fingernails.

  • If you wear gloves for yard work, use heavy-duty vinyl gloves instead of gloves made from rubber or latex. The oil from the plant can get through these materials onto your skin.

  • If you are very sensitive or are often exposed to these plants, you can use bentoquatam 5% cream (Ivy Block) on all exposed areas of your skin. This makes a layer of protection between your skin and any sap oil you may touch. Follow directions, because you may need to reapply the cream. Even if you use the cream, still wear long pants and long sleeves.

If you come in contact with the plants:

  • Remove the oil from your skin as soon as possible. This includes under your fingernails. The sooner you wash, the better chance of removing the oil (urushiol). This may help to make the reaction less severe.

  • Gently wash your skin with lukewarm water (not hot) and plain soap 3 times. Rinse after each wash.

  • If you don’t have soap, use alcohol-based wipes to remove the oil.

  • Wash the clothes and shoes you were wearing. The oil can stay on your clothes and spread from person to person.

  • Don’t scratch. Scratching can cause infection.

When should I call my healthcare provider?

Call the healthcare provider right away if any of the below are true:

  • You have inhaled smoke from a burning plant

  • The rash is on your face

  • The rash is near your genitals

  • The rash covers a large area of your body

  • You have large blisters

  • You have swelling

  • Nothing relieves the itching

  • Itching keeps you from sleeping

  • You have a fever of 100.4°f (38°c) or higher, or as directed by your healthcare provider

  • The rash does not go away within a few weeks

Call 911

Call 911 or go to the emergency room if you have:

  • Trouble swallowing

  • Trouble breathing

  • Swelling on your face or near your eyes

Key points about poison ivy, oak, and sumac rash

  • Poison ivy, poison oak, and poison sumac are plants that cause an allergic rash in most people who touch them. The rash is caused by a reaction to an oil in the plants called urushiol.

  • The rash cannot be spread from person to person by touching the blisters, or from the fluid inside the blisters. But oil that remains on skin, clothes, or shoes can be spread to another person and cause a rash.

  • Treatment is done to reduce itching. Itching can be treated with lotion, cream, or medicine by mouth.

  • In some cases, you may need urgent treatment if you have a severe reaction and swelling.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • Bring someone with you to help you ask questions and remember what your provider tells you.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

  • Ask if your condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if you do not take the medicine or have the test or procedure.

  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your provider if you have questions.

Online Medical Reviewer: Kevin Berman, MD
Online Medical Reviewer: Louise Cunningham, RN
Online Medical Reviewer: Michael Lehrer, MD
Date Last Reviewed: 11/1/2018
© 2000-2019 The StayWell Company, LLC. 800 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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