Several phrases have evolved to help remember how to identify poison ivy. Learn those phrases below.
Poison ivy is the most common cause of plant-induced skin reactions (phytodermatitis) in the United States.
- This plant is found in almost every part of the United States except Alaska, Hawaii, and parts of the west coast.
- It generally grows along rivers, lakes, and beaches.
Knowing how it looks like can help prevent the irritating rash poison ivy causes.
Several phrases have evolved to help remember what this plant looks like, thus avoiding coming in contact with it.
- Leaves: “Leaves of three, leave them be.” This saying suggests the way poison ivy leaves are arranged in groups of three or trifoliate patterns. The leaves have pointed tips with coarsely serrated or toothed margins although the leaf margins may appear smooth as well. The leaf surface may be dull or glossy.
- Vine: “Hairy vine, not a friend of mine.” The vine may appear to be having fine hair-like structures on its surface. Poison ivy may grow as a climber straggling vine or a sprawling shrub (western poison ivy).
- Stem: “Longer middle stem, don’t touch them.” The stem or stalk of the middle leaflet is quite long with shorter stalks on the side leaflets.
- Flowers: Flowers appear greenish and grow in loose clusters. They have tiny petals, about 3 mm wide.
- Fruits: The fruits are typically seen in autumn and look like berries although they are quite hard. They appear whitish and contain a single seed.
Here is a breakdown of the differences between poison ivy, poison oak, and poison sumac:
Table. Poison ivy vs. poison oak vs. poison sumac
A cluster of three leaves
Green, yellow, or red
A cluster of three leaves
Green and may have yellow-white berries
Up to 13 leaflets
Orange, green, yellow, or red
What are the symptoms of poison ivy rash?
The symptoms of a poison ivy rash occur due to the resinous substance called urushiol.
If a person comes in contact with the plant or an object (such as shoes) or pet fur contaminated by this resin, they may develop:
- Pruritus or itching
- Skin redness
- Blisters that often weep
- Black spots or streaks
- Red streaks on the skin
The fluid from the blisters does not contain urushiol; thus, it will not cause the spread of the rash to others.
Skin rash due to poison ivy typically appears within 4 hours to 10 days after exposure to the plant. The blisters generally crust over and clear in two to three weeks.
The severity of symptoms and the timing of their appearance depending on individual sensitivity and the amount of contact.
The duration for which the rash may last depends on whether a person was previously exposed to urushiol or not.
- If a person had previously come in contact with poison ivy or other related plants (poison oak or sumac), their rash may clear in 1 to 14 days.
- If, however, you have been exposed for the first time it may take three weeks or more for the rash to go away.
Some people may develop symptoms beyond the skin manifestations, such as coughing, sneezing, and breathing difficulties, as seen in ragweed allergies. Respiratory symptoms (such as coughing and trouble breathing) are particularly seen on inhaling the smoke from a burning poison ivy plant.
What should I do if I come in contact with poison ivy?
If a person comes in contact with poison ivy, they must:
- Immediately wash the skin well with soap and water. Rinse the skin with rubbing alcohol, specialized poison plant washes, degreasing soap (such as dishwashing soap) or detergent, and lots of water.
- Change into clean clothes.
- Scrub the underside of the nails with a brush.
- To get relief from skin irritation and rash:
- Apply ice or cold compresses, calamine lotion, or hydrocortisone cream (according to label instructions)
- Avoid applying any cream or lotion to broken skin or open blisters
- Take oatmeal baths
- To reduce blistering, make a mixture of a tablespoon of white vinegar in a liter of water and compress the areas for 15 minutes two times a day.
- For reducing itching, one may take over-the-counter antihistamines, such as diphenhydramine, following label instructions. Avoid giving antihistamines to children without consulting a doctor.
- Seek immediate medical attention in case of:
- Severe rashes
- Swelling on the face or genitals
- Dizziness or fainting
- Difficulty breathing
- History of a severe allergic reaction in the past
- Fever (temperature above 100°F)
- Pus discharge from the rash
Rosacea, Acne, Shingles, Covid-19 Rashes: Common Adult Skin Diseases
Medically Reviewed on 1/19/2022
Image Source: iStock Images
DermNet New Zealand. Plant dermatitis. https://dermnetnz.org/topics/plant-dermatitis/
American Academy of Dermatology. Poison ivy, oak, and sumac: what does the rash look like? https://www.aad.org/public/everyday-care/itchy-skin/poison-ivy/what-rash-looks-like
American Museum of Natural History. Tips to Identify Poison Ivy. https://www.amnh.org/learn-teach/curriculum-collections/biodiversity-counts/plant-identification/tips-to-identify-poison-ivy