What does poison oak look like? Tips for hiking in Oregon, Washington

Pacific poison oak is found throughout Western Oregon and Washington and can cause painful rashes and blisters. Luckily, the plant is avoidable if you know what to look for.

PORTLAND, Ore. (KOIN) — Pacific poison oak is found throughout Western Oregon and Washington and can cause painful rashes and blisters. Luckily, the plant is avoidable if you know what to look for.

Oregon State Parks warns visitors that poison oak is very common in hiking areas. However, the plant changes its appearance throughout the seasons, and people should be aware of its different variations before hitting the trails. 

The Food and Drug Administration states that poison oak can grow as shrubs or long vines capable of climbing trees. In shady areas, poison oak favors its vine form and in full sunlight, the plant punches into dense shrub thickets.

The plant’s lobed, rounded leaves are similar in appearance to oak leaves and grow in groups of three. In the early spring and late fall, poison oak leaves turn bright red and in the summer the leaves are a deep green. Pacific poison oak blooms from March to June. During this time the plant develops star-shaped green or white flowers. In the summer, the flowers mature and form greenish-white berries that linger into the fall and winter.

Poison oak, like poison ivy and poison sumac, contains the allergen urushiol. Urushiol is present in the plant year-round and contact with the oily resin can cause an immediate or delayed reaction in humans.

“First comes the itching, then a red rash, and then blisters,” the FDA states. “These symptoms of poison ivy, poison oak, and poison sumac can emerge any time from a few hours to several days after exposure to the plant oil found in the sap of these poisonous plants. The culprit: the urushiol oil.”

Urushiol oil can linger on clothing or even pets. Anyone who comes in contact with poison oak should immediately shower in very cold water to close their skin pores and reduce the amount of urushiol that’s absorbed into the skin, Oregon State Parks recommends. Strong soaps like Tecnu are also recommended to help remove the oil from the skin.

Oregon State University warns that, if burned, poison oak can also irritate the lungs.

“Exposure to urushiol can cause an allergic contact dermatitis reaction that includes painful irritation and blistering of the skin and, if inhaled in smoke, the lungs,” the OSU website states. “Individual reactions vary from extreme susceptibility to near-immunity. Many people are immune when young but suddenly or gradually become sensitive with age, possibly due to sensitization through repeated exposure. These plants can substantially limit the use and enjoyment of our natural environment.”

The FDA offers the following tips for treating poison oak:

• Don’t scratch the blisters. Bacteria from under your fingernails can get into them and cause an infection. The rash, blisters, and itch normally disappear in several weeks without any treatment.

You can relieve the itch by:

• Using wet compresses or soaking in cool water.
• Applying over-the-counter topical corticosteroid preparations or taking prescription oral corticosteroids.
• Applying topical OTC skin protectants, such as zinc acetate, zinc carbonate, zinc oxide, and calamine dry the oozing and weeping of poison ivy, poison oak, and poison sumac. Protectants such as baking soda or colloidal oatmeal relieve minor irritation and itching. Aluminum acetate is an astringent that relieves rash.

See a doctor if:

• You have a temperature over 100 degrees Fahrenheit.
• There is pus, soft yellow scabs, or tenderness on the rash.
• The itching gets worse or keeps you awake at night.
• The rash spreads to your eyes, mouth, genital area, or covers more than one-fourth of your skin area.
• The rash is not improving within a few weeks.
• The rash is widespread and severe.
• You have difficulty breathing.