How to Identify the Plant That Causes the Rash

Many plants can cause rashes. People with sensitive skin may experience skin irritation when exposed to plant matter without protective equipment such as gloves. But some plants are more likely to cause the dreaded itching than others. For example, poison ivy is known for causing painful, itchy rashes.

This article outlines several common rash-causing plants you should avoid, along with symptoms to look out for and when to see a healthcare provider.

plants to avoid

Poison Ivy, Poison Oak, and Poison Sumac

Most people are allergic to the oil in the poison ivy plant, called urushiol. When it comes into contact with the skin, it can cause a rash. Other plants that also contain this oil include poison oak and poison sumac.

The severity of the rash depends on how much and how long you have been in contact with the plant.

Keep in mind that after touching any of these, you may have only a mild rash or no rash at all. But the next time you touch a plant, your reaction may be different, so be careful no matter what.

A rash occurs when your skin comes into contact with a plant and you develop red, itchy bumps and blisters on your skin. If you’ve never been exposed before, it may take two to three weeks for the rash to develop. If you’ve had a rash before, it may appear within a few hours of exposure.

If you’ve never had a poison ivy rash before, or if you’ve had a rash from these plants before, it may last for about three weeks or between a day and two weeks.

Treatment usually involves waiting for things to end and controlling the intense itching. Options for relieving itching include:

  • cold compress
  • Antihistamines such as Benadryl (diphenhydramine)
  • topical creams or lotions containing calamine or hydrocortisone
  • Warm oatmeal bath (soak 1 cup of colloidal oatmeal in a bucket of warm water for 15 to 20 minutes)

Identify Poison Ivy, Poison Oak, and Poison Sumac

Remember the rule: “Three leaves, go with the flow.” Poison oak and poison ivy look similar because they both have three-leaf patterns on their stems. Poison sumac has clusters of leaves—usually 7 to 13.

Wood Nettle (Stinging Nettle)

The bristles of this perennial (meaning it regrows every year) contain toxins that can cause skin irritation upon contact. The leaves and stems have these tiny irritating hairs.

Itching, rash, and hives (raised, red, itchy bumps) appear shortly after the hair touches the skin. Fortunately, the itching and burning that occurs after exposure to nettle usually subside within a few hours.

Identifying Wood Nettles

Wood nettle, or stinging nettle, can grow to 5 feet tall and have pointed, toothed leaves.


You probably know that ragweed can cause sneezing and sniffling allergies, but did you know that this plant can also cause skin irritation? If you are allergic to ragweed, you may also develop hives if you come into physical contact with the plant or its pollen.

Identify ragweed

There are different species of ragweed, but the common ragweed is a tall plant with fern-like leaves. In late summer, the plant also produces green flowers.

lead grass

Leadwort, or graphite, is a shrub commonly grown as a hedge. If you come into contact with the sap, leaves, stems, or roots of the shrub, you may experience a skin reaction that causes blistering and a rash.

Identify lead

This climbing plant has clusters of blue, white, or pink flowers.


These delicate-looking flowers are often found in flower arrangements. They’re pretty, but their pollen can trigger allergies, and the sap can cause a nasty skin reaction that can lead to rashes.

Identify baby’s breath

This perennial grows to 3 feet tall and features branching clusters of hundreds of small white flowers.

giant hogweed

The sap from this tall plant with large flower clusters can cause severe skin irritation in some people. If you have giant hogweed juice on your skin and leave it in the sun, the combination of the two can cause painful skin blisters. In some people, the sap also produces black or purple scars.

If you come across a giant hogweed juice, be sure to cover the area until you can get out of the sun and wash off the clear, watery liquid as quickly as possible.

If your plants have minor burns, try aloe vera or other topical creams to soothe the skin and reduce swelling. Severe irritation requires a visit to your healthcare provider.

Once the skin is exposed to hogweed juice, it becomes more sensitive to the sun. This increased sunlight sensitivity can last for years.

Identifying giant hogweed

This very tall umbrella plant has large clusters of flowers at the top. It can grow up to 14 feet tall with large leaves that can span up to 5 feet.

Giant hogweed in bloom.

Symptoms of Plant Rash

Many rashes have a similar appearance. However, if you develop a rash after coming into contact with plants, plant material may be the culprit.

Plant rashes may also:

  • is red
  • involves bumps or streaks
  • blistering
  • cause skin swelling
  • cause severe itching

general treatment

Treatment for a plant rash largely depends on the severity of the rash. But the following first aid tips will work in most situations:

  • Wash the area with dish soap to remove any vegetable oils that may be causing irritation.
  • Wash your hands to avoid spreading the rash to other areas.
  • Use topical creams or lotions, antihistamines, cold compresses, or oatmeal baths to manage pain and itching.

When to see a healthcare provider

If you are unsure of the cause of the rash, you should see your healthcare provider. It’s also a good idea to see your doctor if the rash doesn’t go away or you suspect an infection. Signs of skin infection include redness, swelling, sores, and pus.

An infection can occur when a plant rash becomes infected with bacteria, or you may have a contagious rash instead of a plant rash. You may have other signs, such as a fever, and a rash from an infection.

If you have a severe allergic reaction that makes it hard to breathe, call 911 or be taken to the emergency room.


Many plants can cause skin irritation, which can lead to a rash. These include poison ivy, poison oak, poison sumac, stinging nettle, ragweed, leadweed, baby’s breath, and giant hogweed. Usually, treatment involves controlling symptoms until the rash goes away.

VigorTip words

If you’re not sure if your rash is plant-related, be sure to see a healthcare provider, as many rashes look similar, including contagious rashes. Most plant rashes go away on their own without medical intervention.

Frequently Asked Questions

  • What plants can cause rashes?

    Many plants can cause skin irritation, but common culprits include poison ivy, poison oak, poison sumac, hogweed, baby’s breath, lead grass, nettle, and ragweed.

  • How can I tell if my rash is from a plant?

    If you’ve recently been exposed to plant material, the plant may be the cause of your rash. If you are unsure, consult your healthcare provider for a diagnosis.

  • Do houseplants give you rashes?

    Yes. Many plants can cause skin irritation, especially in people with sensitive skin. In some people, even tomatoes can cause a rash. This is why it is important to wear gloves when handling plant material.