Poison Ivy

Background

What is poison ivy?

Poison ivy is a plant found in the Toxicodendron genus, which also includes poison oak, poison sumac, and the Chinese lacquer tree. It is native to North America and grows as a vine or shrub with leaves in groups of three. The leaves change color from green to red in the fall.

How can I identify poison ivy?

You can use the saying "leaves of three, leave it be" as a starting point, but it shouldn't be the only method you rely on. Eastern poison ivy is a vine with almond-shaped leaves in groups of three, while Western poison ivy is a shrub with small yellow berries. Look for leaves that change color in the fall and avoid touching plants with these features.

What is urushiol and why is it dangerous?

Urushiol is a chemical found in the sap of Toxicodendron plants, including poison ivy. It is responsible for causing contact dermatitis, an allergic skin reaction, when it comes into contact with human skin. Urushiol is lipophilic, meaning it is quickly absorbed by the skin upon exposure.

What happens if I touch poison ivy?

If you touch poison ivy, you may develop a rash called Toxicodendron dermatitis. This usually gets better on its own within a couple of weeks.

What should I do immediately after touching poison ivy?

After touching poison ivy, you should rinse the area with soap and water right away and clean your clothes. Make sure to clean under your fingernails too, as they can often be overlooked.

What can I do at home to help with the itching?

You can try cool, moist compresses, oatmeal baths, calamine lotion, and over-the-counter creams. Some people also find relief with homeopathic oral preparations of poison ivy, but more research is needed to prove their effectiveness.

Are antihistamines effective against the itch caused by poison ivy?

Antihistamines, commonly used for allergies, are often taken to decrease itching, but they may not work well for poison ivy rashes. They can make you sleepy, though, which might help you avoid scratching.

Treatment

How are severe poison ivy rashes treated?

Severe poison ivy rashes may be treated with topical or systemic corticosteroids. These are types of medications that can reduce inflammation. If the rash is severe, your doctor may prescribe a dose of a medicine called prednisone for 5-7 days to relieve itchines.

What are common topical (cream based) treatments for Poison Ivy?

Your doctor may prescribe any of the following or equivalent strength corticosteroids:

• Betamethasone valerate 0.1% cream applied 3x/day for 7-10 days

• Mometasone furoate 0.1% cream / ointment applied 3x/day for 7-10 days

What are oral (pill based) treatments for Poison Ivy?

Your doctor may prescribe a dose of oral prednisone for 3-5 days. Oral steroids are used of extensive contact dermatitis and carry rare side effect risks (avascular necrosis of jaw or hip)

• Prednisone 25-50mg once daily for 3-7 days

Monitoring

What should I monitor for post-treatment?

You should monitor for increasing redness, warmth or discharge from the site of a healing contact site. This can indicate a secondary skin infection, which can result in a local infection (cellulitis) or a systemic infection (sepsis) that can become dangerous and life-threatening. Cellulitis and sepsis are exceedingly rare following contact dermatitis.

References

1. Lofgran T, Mahabal GD. Toxicodendron Toxicity. [Updated 2023 Feb 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557866/

2. Sheehan, M.P. Avocational Contact Dermatitis—Pearls for Recognition and Management. Curr Treat Options Allergy 2, 322–332 (2015). https://doi.org/10.1007/s40521-015-0065-x

3. Koch, P. Occupational Contact Dermatitis. Am J Clin Dermatol 2, 353–365 (2001). https://doi.org/10.2165/00128071-200102060-00002