Plant Dermatitis 

Poison ivy, poison oak, and poison sumac are very common poisonous plants and grow everywhere in the United States except Hawaii and Alaska. These plants produce an oil called urushiol which causes people to break out in an irritating, itchy skin rash. Typically, rashes from exposure to poisonous plants resolve in a few weeks and, for most people, can be treated with over the counter (OTC) medications; however, medical evaluation and treatment may be necessary for some people.

Most people who come into contact with poison plant oil develop symptoms, even if only exposed to a small amount of the plant’s oil. Depending on a person’s skin sensitivity, the rash and itching may develop within a few hours or a few days after contact with the poison plant oil; however, it may take as long as 21 days for people not previously exposed.

What Do the Plants Look Like?

Poison Ivy – each leaf of the poison ivy plant has three leaflets and grows on a thornless shrub or hairy, ropelike vine. See also How to Identify Poison Ivy.

Poison Oak – leaves have three leaflets (like poison ivy) but have rounded tips with a fuzzy, lighter colored underside which grows as a shrub or vine. See also The Four-Season Field Guide to Poison Oak.

Poison Sumac – each leaf has clusters of 7-13 smooth leaflets arranged in pairs with drooping clusters of pale yellow, cream-colored, or green berries and grows as a tree (up to 20 feet tall), thriving in wet, swampy regions. See also Poison Sumac Identification Guide.

The general rule for identifying poisonous plants is “leaves of three, let them be”.

Is Plant Dermatitis Contagious?

Plant dermatitis is not spread person to person through contact with the rash because the fluid within the blisters doesn’t contain urushiol oil, but it can be spread through contact with clothes or surfaces that have been directly contaminated with the plant’s oil. This occurs most frequently by coming into contact with a pet’s contaminated fur or with contaminated garden tools or hiking gear.

Treatment

Rashes from poisonous plants generally resolve on their own in 7-14 days so treatment is aimed at relieving the symptoms, mostly the intense itching that is associated with plant dermatitis. Over the counter (OTC) medications such as topical calamine lotion and hydrocortisone cream and oral antihistamines such as diphenhydramine and loratadine can be used to reduce the itching associated with plant dermatitis. Cold compresses and lukewarm baths with colloidal oatmeal may also provide itch relief. Medical evaluation is advised if the rash becomes more severe or forms near the eyes, nose, or mouth or on the genitals, as prescription treatment may be necessary. It is important to avoid scratching and to leave any blisters intact; do not remove or peel at blisters and wash hands often.

Prevention

The most effective way to prevent plant dermatitis is to avoid poisonous plants by learning what they look like. Wearing long sleeves, pants, and gloves when hiking or working outdoors can minimize the risk of exposure. Once contact (or potential contact) has occurred, the following steps are recommended to reduce the effects of exposure: remove and wash clothes promptly after being outdoors, wipe exposed body parts with isopropyl (rubbing) alcohol along with any contaminated items to remove plant oil, use dishwashing soap and cool water to wash hands, and scrub beneath fingernails using a brush.

Resources

• American Academy of Dermatology Association – Poison Ivy, Oak, and Sumac
• Children’s Hospital of Philadelphia – Recognizing Poison Ivy, Oak, and Sumac
• Alabama Cooperative Extension System – Touch-Me-Nots: Poison Ivy, Poison Oak, and Poison Sumac

If you are currently sick or injured and need medical advice, call (858) 534-3300 to speak with a registered nurse who can provide guidance. This service is available 24/7 to all students at no cost. You may also message the nursing team during regular hours via MyStudentChart: Menu > Student Health Ask-a-Nurse.