Poison oak begins leafing out on the shoulder of Middle Trail, Mt. Diablo State Park.
Stay off the shoulder
For us who savor the colors and aromas of spring, the lure of the trail is irresistible. A word about those trails: stay on them. Beneath the genial façade of all this blooming and burgeoning, organisms other than wildflowers are unfurling. Alongside the purple of lupine and the scarlet of paintbrush, something nasty is emerging in crimson: poison oak.
Toxicodendron diversilobum, the poison oak shrub, is scattered throughout California’s most attractive scenery. The pesky plant isn’t unattractive in its own right, especially in spring, when its leaves burst forth in glossy gradations of crimson, and in autumn, when they acquire a rusty hue. But its beauty – and menace – is skin deep.
Poison oak isn’t a member of the oak family, but its lobed leaves resemble those of the oak tree. Its stems put out leaves in clusters of three, and in summer and autumn, the female plants sprout tiny ivory-colored fruits. The time-honored jingle is worth remembering: “Leaves of three, let it be; berries white, poisonous sight.”
What makes poison oak so hazardous to our health is the toxic oil coursing through the resin canals of its roots, stems, leaves and flowers. It’s called urushiol, and it’s strictly weapons grade. An amount covering the head of a pin is all that’s needed to cause a skin rash on 500 people. A mere quarter ounce of it could raise a rash on every person on the planet. And like nuclear waste, urushiol preserves its punch. Specimens of it several centuries old have produced rashes on sensitive people.
The allergic reaction caused by poison oak’s industrial-strength resin is a “cell-mediated immune response.” Does your immune system fire on all cylinders? Then you definitely want to stay out of poison oak’s way. When the urushiol residue on your skin penetrates the epidermal layer and attaches to proteins of deeper skin cell membranes, the attachment triggers an alarm that alerts your T-cells. Look out.
T-cells are the security guards of your circulatory system. They check membrane surfaces for unauthorized personnel, such as viruses, with utmost proficiency. Problem is, when they identify an intruder, those mild-mannered security guards become an army of Terminators. The T-cells go berserk, blasting the urushiol attached to the cell membrane – and everything in the vicinity. This collateral damage produces the blistering rash we know and loathe. Worse yet, the “peak misery” (yes, a technical term) of the response might not appear for days or weeks.
Should you accidentally sideswipe a poison oak plant, the first thing to do is wash the contaminated area thoroughly, some experts say within the first 10 minutes. (Urushiol can’t be rubbed off. Rubbing might work it only deeper into your skin.) Problem is, no trail I’ve ever hiked is equipped with resin-removing soap stations every half mile. If the poison oak allergen has penetrated your epidermal layer, washing won’t help. But if you want to take a shot at washing, consider using an organic solvent such as rubbing alcohol or the cleanser called Tecnu.
Tantalizing but toxic, poison oak flaunts its glossy glory on Canyon View Trail, Sunol Regional Wilderness.
Your skin isn’t the only thing that’ll need washing. Shoes, socks, backpack, all your clothing – wash them thoroughly or throw them away. They’ll recontaminate you if you don’t. But be consoled: the poison oak allergen can’t be spread through blister fluids. After thorough washing, you won’t be contaminating anyone else.
After those rashes and blisters develop, a product called Zanfel might be called for. It claims to attack the urushiol at any stage of development. I’ve found Zanfel helpful in dealing with my own outbreaks. As proactive measures, products such as StokoGard Outdoor Cream can be applied before the hike.
Should you run afoul of poison oak, be prepared to ride out the storm. Outbreaks ranging from mild to moderate can last 16 to 18 days. If you feel your case might be severe, get your rash to a doctor. Poison oak is no joke.
The temptation to wander into off-trail wonders can be strong. If you’re wise, you’ll resist scratching that itch. Succumb to the temptation and another itch awaits, one you’ll be scratching for a long time.