Giant hogweed is a poisonous exotic plant. The sap of giant hogweed contains toxins that are activated by light (natural or artificial UV rays). Contact with giant hogweed sap, combined with exposure to light, causes pain and skin lesions similar to burns.
Painful and sometimes serious lesions may appear up to 48 hours after skin comes into contact with giant hogweed sap. Lesions are characterized by:
Redness and swelling of the skin
Superficial or more serious (first or second-degree) burns
All parts of the body can be affected by sap toxins and light. However, the following parts are especially vulnerable:
The back of hands
When to consult
You should see a doctor if:
A child has come into contact with sap
Sap goes into someone’s eyes
The individual affected has fever
Lesions are serious:
Skin becomes red and swollen on over a third of body part with lesions
There are large blisters (at least 2.5 cm or bigger than a quarter coin)
Lesions appear on several parts of the body
Lesions contain pus (opaque, yellow liquid)
If sap comes into contact with your skin
Remove sap as fast as possible with a paper towel, without rubbing. Avoid spreading sap on skin.
Rinse area of skin affected with water and soap and wash your hands.
Remove clothing and wash them to avoid contaminating other parts of your body or objects.
Avoid exposing affected areas of your skin to natural or artificial light. Wear gloves, pants and a long-sleeve shirt for at least 48 hours. If you have burns, cover affected areas for a week.
Use a sunscreen with a sun protection factor (SPF) of at least 30 for 6 months.
If giant hogweed sap goes into your eyes
Rinse your eyes thoroughly with clear water for at least 10 minutes
Wear sunglasses with dark lenses to avoid exposing your eyes to light
See a doctor as soon as possible
If you have burns on your skin
First-degree burns are superficial and generally do not require specific treatment. If you have pain:
Take a bath in cool water
Prepare compresses and soak them in water. Apply the compresses on your burns for 20 minutes, 4 to 6 times a day
If you have second-degree burns with blisters, contact Info-Santé 811 to obtain further information on treatment of burns. You can also see your doctor for a prescription of appropriate treatment.
Lesions take about a week to heal. Then scars or dark spots may appear on the skin and remain visible for several years.
The affected area may also remain sensitive to light for several months.
People often contact with giant hogweed sap during outdoor activities such as gardening and hiking. Sap can also stick to animal fur, especially dogs, who can then directly contaminate people who touch them.