Poison oak rash is an allergic reaction to the leaves or stems of the western poison oak plant (Toxicodendron diversilobum).
The plant looks like a leafy shrub and can grow up to 6 feet tall. In shady areas, it can grow like a climbing vine.
The leaves typically come in groups of three — though you might find them in groups of five or seven as well. The plant may have yellow or green flowers or yellow-green berries, depending on the time of year.
Like poison ivy and poison sumac, poison oak releases an oil called urushiol when it sustains damage. Your skin absorbs this allergen when you touch the plant.
Around 50 to 75 percent of the adult population in the United States is sensitive to urushiol, according to 2019 research.
The best way to prevent an allergic reaction is to avoid initial contact with poison oak.
Below are pictures of poison oak rash on different skin types.
If you have had a poison oak rash before, symptoms may appear 1 to 3 days after exposure. However, if you have never been in contact with the plant before, it may take 2 to 3 weeks before you experience a rash.
The first symptom you will experience is a rash in the place where you came into contact with the poison oak. The medical term for a rash from urushiol is Toxicodendron dermatitis.
Following exposure to the oil from poison oak, you may experience the following stages of symptoms:
- Skin itching. The site of exposure may initially feel itchy, or you may experience a stinging sensation.
- Rash. As your reaction progresses, a rash will form. This may appear red or pink on light skin. On black or brown skin tones, the rash may appear purple, gray, black, or darker than the surrounding area of skin. This rash will be worst in patches of skin that had direct contact with urushiol.
- Blisters.Blisters will begin to form within your rash. These may grow in size and begin to ooze liquid. This liquid is not contagious.
- Healing. As your blisters ooze or burst, they will begin to dry out. They will eventually form a crust once fully dry and begin to heal. This can take 2 to 3 weeks, and you may still experience itching in the meantime.
You may be able to reduce symptoms of poison oak rash with several treatments. These include over-the-counter (OTC) and prescription medications, as well as home remedies.
Poison oak rash is typically a self-healing condition. However, some medications may help reduce symptoms of itching and assist the natural healing processes.
and other soothing treatments to reduce itching symptoms
- topical or systemic corticosteroids
- aluminum hydroxide gel, zinc acetate, or zinc oxide to dry out blisters
Most of the time, you can treat poison oak rash at home.
If you think you’ve been in contact with poison oak, it is important to wash your body well with plenty of lukewarm water and soap, according to the Food and Drug Administration (FDA) . When doing so, you should pay special attention to your hands, fingernails, and whatever skin may have been in contact with the plant.
The oils from the plant can remain on fabric and other materials, which can give you another rash. You should wash clothing and anything else that may have come into contact with the plant.
The rash can be itchy, and the urge to scratch may be strong. However, scratching rashes and around blisters can break your skin barrier and cause an infection. You can take lukewarm baths or cool showers to ease itching.
If you’re allergic to something, the reaction has the potential to be stronger each time you’re in contact with the allergen. Signs of a severe allergic reaction include:
- difficulty breathing
- eye or facial swelling
- rash on your face, lips, eyes, or genitals
- signs of infection, such as pus or yellow fluid leaking from blisters or blisters that have an odor
These symptoms can be life threatening and require immediate medical attention.
Poison oak rash is not contagious.
Direct contact with the oil from poison oak is the only cause of allergic reactions. This may be from touching the plant itself or from touching materials that have this oil on them.
However, there is no poison oak oil in sores or blisters. You will not spread the rash by touching these and then touching other parts of your body, items around you, or other people.
Last medically reviewed on December 13, 2021
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- Identifying poisonous plants. (2018).
- Kim Y, et al. (2019). Poison ivy, oak, and sumac dermatitis: What is known and what is new?
- Lofgran T, et al. (2021). Toxicodendron toxicity.
- Outsmarting poison ivy and other poisonous plants. (2021).
- Poison ivy, oak, and sumac: Who gets a rash, and is it contagious? (n.d.).
- Poisonous plants. (2018).
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