Hikers, backcountry adventurers and weekend wanderers, rejoice! For many in the Pacific Northwest, summer means a lot of trail time and plenty of Insta-worthy moments.
But those lush, winding paths can also come with a few prickly surprises, from plants that cause mild irritation to those that can leave you seriously uncomfortable. Knowing what to watch out for – and when a rash or reaction needs medical attention – can help keep your summer adventures on track.
What poisonous plants are common in Washington and Idaho?
While most of the region’s flora is fairly friendly, there are a handful of plants that can cause painful skin reactions after contact.
For trail users, the most common plants to watch for are:
- Pacific poison oak can cause an itchy, blistering rash after contact with urushiol, an oily substance found throughout the plant. While it is most common in western Washington and often mistaken for poison ivy, hikers may also encounter it in some areas of Idaho.
- Stinging nettle is widespread in both states, especially in moist, shaded areas. Tiny hairs on the plant can cause an immediate burning or prickling sensation.
- Poison ivy is primarily found in eastern Washington and parts of Idaho. Like poison oak, it contains an oil that can cause an allergic skin reaction.
- Giant hogweed is most often found on Washington’s west side. Its sap can make skin extremely sensitive to sunlight, leading to painful burns and blistering.
- Common cow parsnip grows in moist areas along trails, roadsides and streambanks. The plant’s sap can cause skin irritation and, when combined with sunlight, may lead to redness, blistering or other sun-sensitive reactions.
As a general rule, it’s best to admire unfamiliar plants from a distance and stay on established trails whenever possible.
What kinds of skin reactions can poisonous plants cause?
Not every poisonous plant causes the same reaction. Depending on the plant, you may experience:
- An allergic rash
- Skin irritation from tiny hairs or sap
- Sun sensitivity, which can occur after contact with plants like common cow parsnip or giant hogweed
- A skin infection if excessive scratching breaks the skin
Because many skin conditions can look alike, it isn’t always easy to tell whether a rash is caused by a plant, an insect bite or another skin condition.
Look, don’t taste
Some plants found in Washington and northern Idaho, including western water hemlock, poison hemlock and climbing nightshade, are poisonous if eaten rather than touched. If you think you or a child may have eaten an unfamiliar plant or berry, contact a health care provider or poison control right away.
How do I know if I touched a poisonous plant?
Plant-related rashes aren’t always easy to identify. Some reactions happen immediately, while others may take several hours – or even days – to develop.
Common signs include:
- Red, itchy skin (often intense itching)
- Raised bumps or streaky rash lines
- Blisters that may weep or crust
- Swelling, especially around the face, eyes or hands
If a rash follows the path where a plant brushed your skin, there’s a good chance you’ve encountered a problematic plant.
What can I do at home for a plant-related rash?
If you think you’ve come into contact with a poisonous or irritating plant, acting quickly may help reduce your reaction.
- Wash the area as soon as possible with soap and cool water to remove plant oils or sap from your skin. Also wash clothing, shoes and gear.
- Apply cool compresses to soothe itching and reduce discomfort.
- Try over-the-counter anti-itch treatment, such as calamine lotion, hydrocortisone cream or an oral antihistamine (i.e., Benadryl)
- Take a lukewarm bath. Colloidal oatmeal baths can help calm irritated skin.
- Avoid scratching, which can worsen irritation and increase the risk of infection.
- Stay out of the sun if you’ve come in contact with giant hogweed or common cow parsnip. Protect the affected area from sunlight, which can make the reaction worse.
Most mild plant-related rashes improve within a few days to a couple of weeks.
Pups and poisonous plants
If your dog has brushed up against a poisonous or irritating plant, bathe them with lukewarm water and mild soap to help remove plant oils or residue. Wear rubber gloves to protect your own skin.
How can I protect myself from poisonous plants?
A little preparation can help prevent an itchy ending to an otherwise great hike.
- Stay on established trails whenever possible
- Avoid touching unfamiliar plants
- Wear long sleeves, long pants and closed-toe shoes when hiking through brush
- Learn to identify common poisonous or irritating plants before heading outdoors
- Wash your hands, clothing and gear if you think you've brushed against a poisonous plant
- Keep pets on the trail whenever possible
Want to learn what these plants look like before you hit the trail? The Washington Trails Association hasa helpful guide with photos of common poisonous plants.
When should I get medical care for a rash or hives?
Most mild plant-related rashes can be treated at home. But it may be time to seek medical care if:
- Your rash is spreading quickly or covers a large area
- Blisters are severe, widespread or leaking heavily
- The rash involves your eyes, face or genitals
- Itching is severe enough to interfere with your sleep or daily activities
- You develop a fever along with the rash
- Symptoms aren’t improving after several days of at-home care
- You’re not sure whether your rash is from a poisonous plant or other condition
Itching for relief?
Plants aren’t the only thing that can dampen summer fun. Learn about other common summer skin conditions and how to stay safe and comfortable.
Relief starts at Indigo
Don’t let an unexpected encounter with a poisonous plant put the brakes on your outdoor adventure. Indigo Urgent Care is here to help with most minor illnesses and injuries, including mild plant-related rashes.
Our urgent care clinicians can evaluate your rash, help identify the cause and recommend treatment – even if you’re miles from the trailhead. With Indigo Virtual Care, you can meet face-to-face with a clinician from wherever your PNW summer adventures take you. Whether in person at our Washington and Idaho locations or virtually, we’re here 8 am to 8 pm every day, including weekends and holidays.
It’s a good idea to visit your nearest emergency department if your rash:
- Covers your body
- Comes with a high fever
- Appears suddenly and spreads rapidly
- Blisters
- Affects the area around your eyes, face or genitals
- Becomes increasingly painful
- It’s itchy and has yellow or green fluid, or you notice swelling, crusting, pain and warmth in the area of the rash or a red streak extending from it
