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Plants that give you rashes: 7 plants that will make you sting, itch and blister


7 plants that will make you sting, itch and blister

Marcus Schneck | [email protected]

Seven plants that will make you sting, itch and blister

Many plants cause skin irritation in humans. Different people react to the toxins in those plants differently and at different times in their lives.

Rash-, blister- and pain-causing toxins in many wild plants are everywhere in Pennsylvania, waiting for the slightest contact with some unsuspecting human. Depending upon your susceptibility, your reaction to some of them can range from mild to severe and requiring medical attention.

Here are seven common toxic plants that can give you a really bad day.

Marcus Schneck | [email protected]

Leaves of three, let it be

The trademark “leaves of three” makes poison ivy one of the easiest rash-makers to identify. It’s called trifoliate leaves, which means three leaves sprout at the same point on the stem.  Poison ivy can grow as a vine, low shrub or ground cover. Poison ivy bears its fruit as clusters of greenish-white drupes, which are fleshy fruits each with a hard stone enclosing a seed inside.

The toxin, urushiol oil, is in the sap of the plant. Touching the plant can cause skin irritation, rashes and blisters.

Marcus Schneck | [email protected]

Close relative of poison ivy

Like its cousin, poison oak carries it leaves in trifoliate patterns on the stem. However, the leaves of the poison oak look like hairy oak leaves. Poison oak also can grow as a vine or shrub, and also bears its fruit as clusters of greenish-white drupes.

The same toxin, urushiol oil, as in poison ivy, causes the skin irritation, rashes and blisters from poison oak contact.

Marcus Schneck | [email protected]

Poison sumac

Growing as a tall shrub or small tree to a height of 6-30 feet, poison sumac carries the same urushiol oil as poison ivy and poison oak, but in higher concentrations. Some botanists rate poison sumac as the most toxic plant in North America.

Skin reaction to poison sumac includes painful swellings and eruptions, but if the smoke from burning sumac leaves is inhaled the result can be a life-threatening pulmonary edema, whereby fluid enters the lungs.

Poison sumac normally grows in wet areas.

Marcus Schneck | [email protected]

Giant hogweed

An invader from Asia, giant hogweed was introduced to the U.S. in the early 20th century and is now growing throughout the northeastern and mid-Atlantic U.S. It’s a giant member of the carrot family, growing as tall as 14 feet or more, with hollow stems 2-4 inches in diameter and large compound leaves as much as five feet wide. The tiny white flowers grow in clusters similar to the flowerheads of Queen Anne’s lace, but much larger.

The sap of giant hogweed, in combination with moisture and sunlight, can cause severe skin and eye irritation, painful blistering, permanent scarring and blindness.

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Wild parsnip

Also known as the poison parsnip, the wild parsnip is an aggressively invasive, non-native that has taken hold throughout the eastern U.S. It tends to colonize disturbed sites quickly. It grows 2-5 feet tall with tooth-edged basal leaves and small yellow flowers that grow in cluster similar to those of the Queen Anne’s lace.

Chemicals in the sap contains photosensitizing chemical compounds that are activated by ultraviolet radiation in sunlight. Exposure produces burnlike blisters.

Marcus Schneck | [email protected]

Stinging nettle

Native to Europe and Asia, stinging nettle found its way to North America and now grows coast to coast. It generally grows in highly invasive patches of single-stem plants 3-4 feet tall.

The stinging nettle is covered in small hairs. When touched those hairs “sting” with a nasty blend of histamine, serotonin, acetylcholine and formic acid. Skin reaction of localized pain, reddish swelling, itching and numbness generally last for a few hours maximum before resolving on their own.

Marcus Schneck | [email protected]

Wood nettle

Also known as Canada nettle, the low-standing wood nettle grows in open woods with moist soils, along streams and in drainages. It often grows into small clumps. Each plant has both stinging and non-stinging hairs on the foliage and the stems. It has small, whitish green flowers spring to early fall.

Contact with the stinging hairs will produce a painful burning sensation, following by rash and blistering, which can last for several days.

Marcus Schneck | [email protected]

More scary stuff

For another look at additional scariness lurking in the Pennsylvania outdoors, check out this slide show on wildlife-borne diseases in Pennsylvania.

Outsmarting Poison Ivy and Other Poisonous Plants