What is poison ivy?
Poison ivy (also called Toxicodendron radicans) is a shrub that grows almost everywhere in the United States. It has almond-shaped leaves that range in color from light to dark green and are arranged in clusters of three leaves; one in the center and one either side. Mature leaves are shiny with a smooth or slightly notched edge.
What causes a poison ivy rash?
The sap of the poison ivy plant contains an oil called urushiol which causes an allergic reaction and rash within 12 to 48 hours in 85% of people it encounters. Contact with the oil doesn’t have to be direct either, it can linger on clothes, gardening equipment, shoes, sports gear, pets and cause a reaction weeks later if it gets on a person’s skin.
What are the symptoms of poison ivy?
The rash from poison ivy is called allergic contact dermatitis and can start developing within 12 hours but may take a few days to fully develop.
Typical symptoms include:
- Intense redness
- Itching
- Multiple, painful blisters
- Swelling
- Thin red lines of rash where you have brushed against the edge of the leaves directly.
The rash typically just covers the area of skin that has contacted the oil. However, the rash may be more widespread if a pet has rubbed against you that has oil on its fur or if you touch lawn clippings when emptying the mower bag.
The reaction is usually not as severe in older people, particularly in people who have been exposed to the plant in the past. The rash will usually get better within a couple of weeks, even without treatment.
How is poison ivy treated?
Most instances of poison ivy rash do not need to be treated by a doctor; however, you should go to the emergency room if you have shortness of breath, trouble swallowing, the rash is on your face or genitals, covers a large area of your body, or if the rash has caused swelling. Widespread rashes may require treatment with a prescription corticosteroid, or if infected, an antibiotic.
Treatments that may be considered include:
- An over the counter antihistamine, such as fexofenadine or diphenhydramine
- Calamine lotion or hydrocortisone cream to stop the itching
- Frequent warm baths in water containing an oatmeal product or apply cool, wet compresses to help relieve the itch
- Topical remedies such as aloe vera, apple cider vinegar, or witch hazel.
If you encounter poison ivy and it touches your skin, you should immediately wash all areas of skin and your clothes that have touched the plant.
