That strange new itch just might be poison oak — Is it a nuisance or a danger?

Poison oak secretes an oily sap on its stems and leaves which causes an allergic reaction and, unfortunately, repeated exposure over time increases sensitivity. You can be exposed to oil from the plant either from the plant itself or without ever coming into contact with the plant simply by touching the oil that has gotten on clothes, shoes, pets, tools, and any number of other things; even smoke from burning plants, which can be a particular hazard as it can cause internal problems, too.

Poison oak.

Despite its name, poison oak is not related to oak trees. It’s actually a dense, leafy shrub that sports a distinctive “leaves-of-three” pattern and is a serious threat to those who are allergic to the plant says California Poison Control System. The poisonous plant is abundantly found throughout California along the coasts, and in forests, grassy hillsides, and recreation areas.

“It takes about one to six days after coming in contact with poison oak, either directly or indirectly, for symptoms to develop,” said Rais Vohra, Medical Director for the Fresno/Madera Division of CPCS. “If the oil from the plant, called urushiol, gets on your skin it can cause an itchy, sometimes painful, rash which then turns into water blisters. One interesting thing about poison oak is that it can’t be spread from person-to-person by touching the rash or the blisters or from the fluid in the blisters; it can only be transmitted through touching the oil.”

He adds, “Most people will not require a trip to the emergency room unless they have a severe reaction, such as trouble breathing, or have inhaled smoke from burning poison oak. However, it’s much better to learn to recognize the plant and avoid it.”

Identifying poison oak 

  • It can be spotted all year long, though it typically changes color from green in the spring to crimson red in the fall.
  • It grows into groups of three leaflets with the center leaflet typically growing longer than the other two.
  • It grows into a dense and leafy shrub, ranging from 1 to 6 feet high.
  • It has a vine-like appearance.
  • It has either glossy or dull leaves.

“Although you will have several days or even weeks of unpleasantness after exposure, poison oak can be safely treated at home by most people,” said Vohra.

Treating poison oak rash 

  • Try not to scratch.
  • Wash itchy and affected areas with lukewarm water right away.
  • Apply rubbing alcohol or over-the-counter skin cleanser to wash away the oil.
  • Apply over-the-counter steroid cream to treat dermatitis (skin inflammation).
  • Apply calamine lotion to help stop the itching.

“Poison oak exposure is more common in warmer weather, when you are more likely to be outdoors,” said Vohra. “So preventative measures, especially if you love to hike, will help you avoid the misery of being affected by poison oak.”

Preventing exposure 

  • Long-sleeved shirt.
  • Long pants.
  • Hats and gloves.
  • Closed-toe shoes or boots.
  • Stay on trails and away from bushes where poison oak may be present.
  • Wash clothes, tools, strollers, wheelchairs, and pets after hiking outdoors as they may have poison oak oil on them.
  • Do not burn poison oak as the smoke can cause irritation.

“If you have any of the following severe or life-threatening symptoms, seek medical attention right away,” said Vohra. “You can also call the Poison Hotline at (800) 222-1222 for additional advice.”

When to seek medical attention 

  • If the rash covers much of your body.
  • If you have many blisters or swelling — especially on your eyelids, face, or genitals.
  • If you have trouble breathing or swallowing.

About the California Poison Control System
Call Poison Control at (800) 222-1222 (number is the same in all states) for questions about poison encounters. Trained pharmacists, nurses and other providers are available to help 24 hours a day, seven days a week. The service is free, confidential and interpreters are available. Get weekly tips about safety by texting TIPS to 20121 for English or texting PUNTOS to 20121 for Spanish. Follow CPCS on Facebook and on Twitter @poisoninfo. CPCS is part of the University of California San Francisco School of Pharmacy and is responsible to the California Emergency Medical Services Authority.