FELTON — Just thinking about it makes me itch.
Or retreat, as was the case during a recent trek in the Santa Cruz Mountains while blindly walking into a swath of poison oak that blanketed a ridge line.
Forget about slithering rattlesnakes. Itch-inducing poison oak is the scourge of the late spring and early summer. After heavy winter rains, it’s difficult to enjoy the great outdoors without encountering the plant botanists call Toxicodendron diversilobum.
Plant scientists say poison oak is more robust and healthy this year because the wet winter created perfect conditions for new growth.
Rubbing up against the three-leaf shrub is messing with fate. This species enjoys a kinship with its evil East Coast cousin poison ivy: they produce a toxic sap called urushiol (oo-ROO-shee-ohl) that causes skin rash in about 85 percent of the population.
Ranger Scott Sipes at Henry Cowell State Park says the only surefire way to stay itch free is to avoid the plant. It takes just a small amount of oil — less than a grain of salt — to trigger a reaction.
But I’ve found it almost impossible to follow the advice after regular forays into coast redwood forests this spring. The result: allergic reactions getting exponentially worse after almost every visit.
Here are some useful tips:
What to look for
The plant can be found in woodlands, chaparral, forests and hillsides from sea level to 5,000 feet in the western United States.
The look changes depending on where it’s growing. In redwood forests and shaded oak woodlands, poison oak grows low to the ground in groups of stalks or as a climbing vine that can extend 100 feet or more.
In open space with direct sunlight, the plant forms a leafy shrub up to six-feet high that often is mistaken for blackberry bushes. The difference is easy to spot: blackberries stalks have thorns, poison oak stems are smooth.
One handy tool for identification can be found at the Rashplants app on iTunes.
Preventative measures
A Capitola friend who spends much of his waking hours in the forests recently extolled the virtues of poison oak tea a “hippie” friend served him many years ago after he’d had some unfortunate contact with the plant. Others say drinking goat’s milk is the way to go, while some swear by special lotions that can be found in drugstores.
Experts recommend wearing long-sleeved shirts, pants and boots when trespassing in poison oak country. Also, wash quickly with cold water after exposure because the oil begins doing its nasty work within 15 minutes of contact. (Warm water opens up the pores, which you do not want!)
A degreasing soap or special scrub wash such as tecnu or Zanfel works best. But even rinsing in cool water can help.
Could you be immune?
Few people truly are immune to poison oak, even if someone has gone decades without an allergic reaction.
Medical literature says that while it is possible to build up an immunity to the oil it is just as likely the reaction gets worse the more times one is exposed.
Odd enemies: Pets & mangoes
Bay Area dermatologist Marie Jhin has treated many patients who contracted the rash from their pets. She said animals who run freely outside should be washed immediately.
The oil, Jhin added, also is found in the skin of mangoes. Those susceptible to poison oak should handle the fruit carefully.
If you do get it…
Many cases can successfully be treated with calamine or aloe vera lotions with the rash lasting from one to three weeks. However, some people need prescription topical steroids or oral medications such as prednisone. Others need antibiotics for an infection.
The American Academy of Dermatology recommends visiting an emergency room if symptoms are severe: having trouble breathing or swallowing, a rash covering most of the body, severe blistering, eyelids swollen shut or a rash on the face or genitals.
But most of the time poison oak is more annoyance than emergency, and well worth the off-the-grid exploration.
If you remember one thing, make it this: Leaves of three, leave them be.
