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Don’t Touch! When Wild Plants Are Poisonous

Tuesday, April 18, 2017 9:04 AM

Summer is known for going outside and enjoying the weather. At this time of year, wild plants are known to be sprouting up. Some are harder to recognize than others, and some can cause severe pain. There is an old plant that is attracting new attention called Wild Parsnip. Skin reactions to Wild Parsnip have been documented in the New England Journal of Medicine as far back as 1967. Not only is the sap of the plant toxic but when also combined with sun exposure, the rash can significantly worsen causing blistering and scarring.  The sap can cause blindness if it gets into the eye.


Wild Parsnip is a new poison plant to look out for, but don’t forget about similar poisonous plants that are a little bit more common. Jennifer S. Kim, MD, Allergist at NorthShore, shares what you should do if in contact with these plants:

Wild Parsnip:

  • Where it grows: Prairies, open fields and bike paths.
  • Appearance: Non-native, yellow weeds.
  • Symptoms: Can cause inflammation and a burning sensation followed by blisters and welts appearing later and overnight.
  • Treatment: Shower immediately and wash all clothing after contact. Stay out of sun and call your doctor, who may recommend topical steroids.  Milder symptoms may be treated with hydrocortisone.

Poison Ivy:

  • Where it grows: In all US states except Alaska, Oregon, Hawaii, California.  Open fields, forest preserves and on roadsides. It can also be found in more common areas such as parks and backyards.
  • Appearance: The color of poison ivy is different each season. In the summer, leaves are usually green. In the fall, they change color with the surrounding trees.  Can grow up to four feet tall as groundcover or climbing vine. The plant’s berries are a grayish-white color.

Poison Oak:

  • Where it grows: Along Pacific Coast and Atlantic Coast. Rare in Midwest. 
  • Appearance: Dense shrub in the sun or climbing vine in the shade and leaves are slightly more jagged. Plant grows up to six feet tall, with green, yellow or white berries, and does a great job camouflaging itself to blend in with the surrounding plants.

Poison Sumac:

  • Where it grows: Wet, flooded or swamp-like areas. Much less common than poison ivy or oak.
  • Appearance: Grows as a shrub or a small tree. Typically 7 to 13 leaflets per stem, veins are always red, with the leaves having pointy tips.  Fruit is a small white or gray berry.

For Poison Ivy, Oak, Sumac, symptoms and treatment are the same:

  • Symptoms: It takes about 4-96 hours for the reaction to take place, and the symptoms you may experience include redness, itching, difficulty breathing and blisters.  New lesions can occur up to 21 days after exposure, which can give the impression that the poison ivy is spreading.  Touching the blisters or the fluid inside the blisters will not spread the rash.
  • Treatment:  Remove any contaminated clothing and gently wash the skin with mild soap and water as soon as possible, including under fingernails.  Try oatmeal baths and cool compresses.  See your doctor if the rash is extensive or affects your face and/or genitals. 

Do you know what poison ivy looks like?