Poison Ivy and Other Skin-Irritating Summer Plants

If you spend time outdoors in summer, you might come in contact with plants that cause skin reactions including rashes, blisters, and hives. Here’s a short guide to irritating summer plants.

Toxic Plants Aren’t Equally Irritating

Some people have allergic reactions to plants that don’t bother most people. The allergic reaction may resemble a rash. However, the rash is triggered by allergic responses inside the body.

Non-allergic plant rashes are caused by toxins that make direct contact with the skin. The toxic agents may be in the milk, sap, or stinging hairs of a plant. When skin contact is made with leaves, stems, and other parts of irritating plants, the toxins cause a rash at the site(s) of contact.

Urushiol Oil Is a Common Cause of Summer Rashes

Urushiol oil causes itching of the skin where it touches the body. A rash soon develops followed by small blisters.

Urushiol oil is found in the sap of:

  • Poison ivy
  • Poison oak
  • Poison sumac

Merely touching the leaves of these plants can transfer the toxic oil to your skin.

Contrary to popular belief, only the part of your skin that touches the plant is affected by the itching and blisters. You can’t spread urushiol oil rashes to other people or to other parts of your body by touching the blisters. It may only seem this way as patches of itching develop at different rates.

Plants Can Make the Sun No Fun

On the extreme end of the toxic-plant spectrum are the plants that cause photodermatitis. Plants in the carrot family are included in this category. Photo-dermatitis-inducing plants cause your skin to swell with giant blisters a few hours after touching the sap and exposing the skin to sunlight.

The agents responsible for the intense reactions are called psoralens. These chemicals can cause severe reactions at exposed sites in some people. Dark streaks may remain on the skin for months after the blisters are healed.

Plants that cause photodermatitis include:

  • Wild parsnip
  • Garden rue
  • Gas plant
  • Fig tree
  • Poison hemlock

Many of the plants in the carrot family have blooms that resemble Queen Anne’s lace. The broad flower clusters may be white or yellow and all face upward in an umbrella-like pattern. Queen Anne’s lace is not toxic and is often used in flower arrangements. However, don’t pick flowers that resemble the blooms unless you’re sure the plant is actually Queen Anne’s lace.

A notorious plant that causes photodermatitis is the giant hogweed. This plant has not been found in Minnesota yet, but you may encounter it in Wisconsin or any of the other states where it’s been discovered.

The giant hogweed lives up to its name by growing up to 15 feet tall. Leaves grow up to five feet in size. Exposure to giant hogweed can cause serious swelling and discoloration of skin.

Stinging Plants Deliver Allergic Reactions

In North America, the stinging nettle is a common cause of itchy, welt-covered skin. Stinging nettles are covered with tiny hairs that pierce the skin when touched.

The hairs don’t just poke into your skin. They also deliver a mini shot of histamine, serotonin, formic acid, and acetylcholine. Formic acid is one of the agents that put the sting in bee and fire-ant stings

Removal of Toxic Plants Requires Care

If you encounter toxic plants on your property, have the plants professionally removed or remove the plants yourself. Your local extension agent can offer advice on removal so you don’t accidentally spread the plant.

Always wear protective clothing, eyewear, and gloves when digging or mowing skin-irritating plants. Don’t burn the plants because the smoke and fumes are damaging too.

Rashes May Be Avoided With Cleanup

If you realize you’ve been in contact with a poisonous plant, take action right away. Plant poisons don’t take long to start causing trouble.

Follow these seven steps after you touch a poisonous plant:

  1. Get out of the sun and go indoors or in the shade.
  2. Wash skin gently with cool water and soap to remove oils.
  3. Rinse skin well and pat dry with a fresh, clean towel.
  4. Don’t scratch, pick, or rub the rash or blisters.
  5. Use cool, wet washcloths or a cool soak to soothe the area.
  6. Apply over-the-counter creams to relieve itching.
  7. Consult with your healthcare provider for prescription ointments if your itch is severe.

Blisters from plant rashes often ooze a clear liquid and then dry into a crust. The oozing-crusting process may repeat as the rash heals. The broken skin is prone to infection during this process, so keep the site of the rash clean and free of debris while it heals.

According to the U.S. Food & Drug Administration, you should call your doctor about any serious rash-related symptoms you’re having including:

  • Rash over one-fourth of your body
  • Fever over 100 degrees Fahrenheit
  • Rash on mouth, eyes, or genitals
  • Rash does not heal after two weeks
  • Soft yellow scabs or pus in rash

If you’re having difficulty breathing, intense pain at the rash site, or the itching is making it impossible for you to sleep, contact your health care provider immediately.

Contact the staff at Stellis Health when you need a medical skin care evaluation for yourself or a member of your family. Our skin care team diagnoses and treats summer rashes for our patients.