Poison ivy, poison sumac, and poison oak are plants that cause most people to have a rash, blisters, and itching after coming in contact with them.
Poison ivy is found throughout the US, except in the southwestern US, Alaska, and Hawaii. It grows in the form of a vine, with a red stem and 3 shiny green leaves.
Poison oak is mainly found in the western US. It grows in the form of a bush and has 3 leaves similar to poison ivy.
Poison sumac grows mainly in the southeastern US. It grows as a woody shrub in damp marshy places. Each stem has pairs of 7 to 13 leaves, with one at the end of the stem.
What causes the rash?
Your body may have an allergic reaction to substances it sees as harmful or foreign. Substances that can cause an allergic reaction are called allergens. Poison ivy, poison sumac, and poison oak have oil that is an allergen. The oil is in the sap of these plants and oozes from any cut or crushed part of the plant, including the roots, stems, and leaves.
The rash happens after touching the plants or coming in contact with anything that carries the oil from the plants, such as clothes, tools, animal fur, or ashes.
The smoke from burning plants can cause severe asthma attacks in those who are allergic to these plants.
What are the symptoms?
Symptoms may include:
Itching, often intense
Red blotches that may be raised or flat
Blisters, which may show up in rows where the plant or sap touched you
If you have a severe reaction, symptoms may include:
Swelling of your throat and eyes, or swelling all over your body
Stomach cramps, nausea, vomiting, diarrhea
Sudden wheezing and trouble breathing from breathing in smoke from burning poison ivy
Usually the rash is first noticed 1 to 2 days after contact. How bad the rash gets depends on:
The thickness of your skin
How allergic you are to the plant
How much of the plant’s oil you were exposed to
How soon you were able to wash off the plantâ€™s oil
How is it diagnosed?
Your provider will ask about your symptoms and medical history and examine your skin. Your healthcare provider will ask if you have recently been in woods, yards, or gardens where the plants are likely to grow or around pets who have been in those areas.
How is it treated?
Most of the time you donâ€™t need to see your healthcare provider for treatment. Right after contact with the plant or oils from the plant, follow these steps:
As soon as possible, preferably within 5 to 10 minutes of contact, rinse exposed skin thoroughly with soap and water (or just water). Be sure to clean under your fingernails. Zanfel is a product made to remove poison ivy, oak, and sumac oils from the skin.
Remove your clothes and shoes. Wash your clothes in detergent and water.
Once you have a rash:
Cover any oozing blisters with a clean gauze bandage soaked in a baking soda and water solution.
Put calamine lotion or ointment on your skin to reduce the redness, ease the itching, and help dry up the blisters.
If you have severe coughing or wheezing, especially with throat swelling, from burning poison ivy, oak, or sumac, you need medical treatment right away.
If the rash is on your face, mouth, eyes, or genitals, or if you have severe symptoms, see your healthcare provider. Your provider may prescribe:
Cream or ointment to stop the itching and other symptoms
Antihistamine pills to help stop itching and any allergic reaction. Do not put antihistamine cream or lotion on your skin if you are taking antihistamine pills.
Anti-inflammatory medicine, such as prednisone, if your rash is severe
Antibiotics if the rash becomes infected
The rash usually takes 1 to 3 weeks to heal.
How can I take care of myself?
Follow the full course of treatment prescribed by your healthcare provider. In addition:
Donâ€™t scratch your skin even though it itches. Scratching may break the skin and cause infection.
Put a moisturizer on your skin right after bathing. Helpful ingredients are petroleum jelly, lanolin, and glycerin. Ask your healthcare provider or pharmacist what you should use.
Put cool, moist cloths on the areas of skin rash to help lessen itching. But do not keep the area covered. The rash will usually heal more quickly if it is left open to the air.
Soak some cloth in aluminum acetate solution (Burrow’s solution) and put the cloth on the rash for 15 to 30 minutes.
Soak in a lukewarm bath with cornstarch (1/2 cup) or an oatmeal product made for skin conditions (available at drugstores) added to the water to help ease the itching.
Take short baths or showers no more than once a day. Use a mild moisturizing soap or nonsoap cleanser. Avoid long, hot baths. Hot water can increase itching. Pat your skin dry with a soft towel. Do not rub your skin dry.
Ask your provider:
How long it will take to recover
What activities you should avoid and when you can return to your normal activities
How to take care of yourself at home
What symptoms or problems you should watch for and what to do if you have them
Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.
What can I do to help prevent a reaction to poison ivy, sumac, or oak?
Know what the plants look like and where they grow so you can avoid them.
Wear long-sleeved shirts and long pants if you are going to be in an area where these plants grow.
You may want to use IvyBlock skin cream, which is made to block poison ivy oil from getting on your skin.
Wash clothes in hot water and detergent to remove any oil that may be on them. Also clean shoes, tools, camping or fishing gear, or anything else that has been in contact with the plants. Wear gloves when you do the washing and cleaning and then throw the gloves away.
Give any outdoor pets a bath if you think they have had contact with the plants. Wear gloves and avoid contact with their fur while bathing them.
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth. Last modified: 2014-07-31 Last reviewed: 2014-07-31
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.