Poison Oak Guide: How to Identify Poison Oak and Treat Rashes

Poison oak is a genus of flowering plants in the sumac family. Poison oak produces the skin-irritating oil urushiol, which can cause allergic reactions and skin rashes. The plant’s leaves emit oil when they are torn or burned. The term poison oak generally refers to two main plant species: Toxicodendron diversilobum, also known as Pacific poison oak or Western poison oak, and Toxicodendron pubescens, commonly called Atlantic poison oak.

Both poison oak species are found in broadleaf forests and grasslands along the eastern and western coasts of North America, predominantly in the United States, with Atlantic poison oak stretching westward to Oklahoma. In the U.S., Hawaii and Alaska are the only two states without poison oak plants.

Identifying poison oak can help you proactively avoid it and steer clear from allergic reactions or potential trips to the emergency room.

1. 1. Shape: You will not find poison oak on oak trees; instead, it gets its name because its foliage resembles oak leaves. Poison oak leaves are oval-shaped, just three to six inches long, and come to a point at the top of the leaf.
2. 2. Trichomes: Poison oak leaves have trichomes, or fine hairs, on both sides.
3. 3. Color: The leaves are a light green color in spring and summer. In the fall, poison oak leaves will turn yellow, bright pink, or red.

Poison oak, poison ivy, and poison sumac all grow throughout North America and release plant oils as allergens. You won’t want to come into contact with any of these poisonous plants, but there are a few simple ways to differentiate them:

Vines or trees: In many cases, poison ivy and poison oak plants resemble each other more. Poison sumac is a shrub or small tree, while poison ivy and poison oak grow as vines or shrubs.
The number of leaves: Poison oak and poison ivy plants will often have groups of three leaves, one in the center and two on each side, while sumac plants grow leaves in groups of seven to 13 (with one at the head of the stem).
Skin irritation: If you encounter any of these leaves, a skin rash will appear within three days. A poison ivy rash can last for as long as three weeks, but you can treat it similarly to a poison oak rash.

There are a few ways hikers and campers can avoid poison oak rashes:

Wear long sleeves and long pants. Poison oak is a poisonous plant that contains urushiol oil, which can cause allergic contact dermatitis. To prevent this when heading to the outdoors, wear long sleeves and long pants to avoid contact.
Wash your pets. If you walk your dog in areas populated with poisonous plants, your pet’s fur might come into contact with urushiol. It may be harder to detect signs of infection on your pet, so be sure to run a bath and wash your pet’s fur after an outing.
Don’t start fires. If you are in an unknown part of the woods, and especially if you have encountered other poisonous plants on your trek, burning a plant that turns out to be poison oak can further release toxic oils. The oils can cause difficulty breathing or other severe allergic reactions.

Poison oak can cause skin rashes, inflammation, and blisters. Fortunately, there are several DIY and over-the-counter remedies available to mitigate the effects of itchy skin or common allergic reactions:

• Wash your skin immediately. Using warm, soapy water or rubbing alcohol, wash the affected area as soon as possible after contacting the plant to remove the urushiol oil from your skin.
• Use cool compresses. Itchy rashes are typical of poison oak exposure. In less severe reactions, cool compresses will help soothe a red rash. Eventually, blisters will open, ooze, and crust over, which means the rash is on the way out. Avoid scratching to expedite recovery.
• Try calamine lotion. Apply calamine lotion or hydrocortisone cream to the affected area to mitigate itching. These over-the-counter lotions will act as a balm to a poison oak rash.
• Create a baking soda salve. You can create a home remedy using baking soda and cool water. Combine three parts baking soda to one part cool water; mix together, pour it onto a rag or paper towel and gently apply to your blisters or skin rash.
• Make an oatmeal bath. Colloidal oatmeal is ground into a very fine powder to add to soaps and lotions. You can find colloidal oatmeal at pharmacies, and when added to bathwater, it can act as a balm for itchy skin. Rashes can spread to various parts of the body, so an oatmeal bath can be an effective way to treat much of your skin.
• Take antihistamines. Taking oral antihistamines such as diphenhydramine can help you sleep better as the itching will subside and allow a better night’s rest.
• Go to the emergency room. In worse cases involving difficulty breathing, swallowing, or other forms of severe reactions, go to an emergency room. After an ER visit, you may need to contact your healthcare provider to find dermatologists who can help treat potential long-term allergic reactions on your skin.

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