Primary Care in Rochester and Kasson

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Poisonous wild plants still pack an unpleasant punch

9/19/2016 by Dr. Jennifer Horn

Whether you're taking a hike or hunting, cleaning up the garden or camping this fall, wild poisonous plants still can pack an itchy, unpleasant and sometimes painful punch. The devilish duo to be aware of and avoid are wild parsnip and poison ivy (and its cousins, poison oak and poison sumac). 

ECH_WildParsnip_01_widgetWild parsnip. This tall, sturdy plant with its flat, umbrella-like blossom sprinkled with tiny yellow flowers has run rampant this season. All it takes is skin contact with its poisonous sap, a little sunlight and yeow! The chemical reaction, called phytophotodermatitis, is so corrosive that it can cause a rash and blistering as bad as second-degree burns. The blisters can take weeks to clear up and may leave scars and skin discoloration. 

A non-native plant, it's found along roadsides and fence rows, the edges of prairie areas, woodlands and trails, and in abandoned fields and unmowed pastures. ECH_Parsnip_03_widgetYour best protection is to wear long sleeves, pants and gloves. If you do come in contact with wild parsnip: 

  • Cover the affected area with a cool, wet cloth
  • If blisters appear, try not to rupture them for as long as possible
  • To avoid infection, keep the area clean and apply antiseptic cream
  • Contact your care team or provider if the blisters get worse or there are signs of infection

ECH_PoisonIvy_01_widgetPoison ivy (poison oak, poison sumac). "Leaves of three, let it be." That's the old trick for identifying and steering clear or poison ivy. Good advice! Poison ivy and its cousins can produce an itchy, long-lasting rash caused by an allergic reaction to the oily resin, called urushiol, which is found in the leaves, stems and roots. 

You can get the oil on your skin not only from the plant, but also from clothing, tools, equipment or animal fur or hair. If you're burning with poison ivy, there's also danger of inhaling the oil, which may cause difficulty breathing. 

If you've come in contact with the oil, wash your skin with soap and water, and even your clothing, as soon as possible to reduce your chance of getting the rash. Treat mild cases of poison ivy rash at home with soothing lotions and cool baths. If the rash is severe or widespread, or on your face or genitals, you may need a prescription medication. 

See your care team or provider if: 

  • Your skin continues to swell
  • The rash affects your eyes, mouth or genitals
  • Blisters are oozing pus
  • You develop a fever greater than 100 F. (37.8 C.)
  • The rash doesn't get better within a few weeks

Allergic reactions to any poisonous plant can be worse after each new exposure, because your body becomes primed to react to the toxins. 

ECH_Nettles_01_widgetStinging nettles. While nettles have been used for centuries in herbal teas and remedies, inadvertently coming in contact with tiny spines on the stalk is plenty painful. These tall, spiky plans grow along streams, woodlands, trails and roadsides. If you come in contact with nettles, wash the area with soap and plenty of water to remove the sting. 

Dr. Jennifer Horn is a family physician in Employee and Community Health's (ECH) Department of Family Medicine. She completed her MD at Mayo Medical School and her residency in Family Medicine at Mayo Clinic Rochester. Her interests include population health, clinical operations and holistic wellness for both patients and employees.