How to Spot and Treat Poison Ivy and Poison Oak

LEXINGTON, Ky. (June 29, 2015) — The quickest way to ruin a fun-filled summer day is to come in contact with a nasty patch of poison ivy or poison oak. Touching any parts of these plants can result in a red and itchy skin rash characterized with tense blisters and bright red lesions. Here’s all you need to know about how to spot and treat the pesky weeds.

Q: What do poison ivy and poison oak look like?

A: Each leaf of both poison ivy and poison oak has three small leaflets and both can grow as shrubs or vines. In the spring, poison ivy grows yellow-green flowers and poison oak may have yellow-white berries.

Q: What causes the rash?

A: The rash is caused by contact with urushiol, a sticky oil found in all parts (leaves, roots, stems), of both alive and dead poison ivy and poison oak. Approximately 85 percent of people will break out in an allergic reaction after touching the plant. The allergic reaction is delayed and usually starts 1-3 days after exposure.

Q: Are poison ivy and poison oak rashes contagious?

A: No, the rash is only spread through the oil. You can't catch a rash from someone else by touching their rash; however, you can get the rash by touching anything that has come in contact with the plant's oil, such as clothes, sporting gear, or especially pet fur.

Q: What are the symptoms?

A: The most common symptoms of the rash are itchiness, red linear streaks or blisters where the plant brushed against the skin, characterized by small to large sized bright red lesions, and blisters that may leak a clear to yellow fluid.

Typically, the rash from poison ivy or poison oak will last about 10 days to three weeks. But in more severe cases, it could take up to six weeks to go away.  It clears much more quickly with medical intervention.

Q: How can the rashes be treated?

A: Immediately after you think you have come in contact with the plant, wash your skin with a mild soap and cool water. It can help reduce the amount of oil that causes the allergic reactions. 

For an effective home treatment, compress the affected areas with a clean cloth soaked in whole milk for 10 to 15 minutes three to four times daily to dry up the blisters, followed by an over-the-counter topical one percent hydrocortisone cream.

Calamine lotion can be an effective astringent. Application of the aloe plant can also help with the itching. Antihistamines like Benadryl are not affective in helping with the rash.

Additionally, make sure you wash your clothes or any other objects that may have come in contact with the plant to prevent the plant’s allergic chemical from spreading even more.  

Medical treatment from a physician would include a prescription topical steroid and systemic steroids to hasten the clearing.

Dr. Stuart Tobin is Division Chief of Dermatology for UK HealthCare.

This column appeared in the June 28, 2015 edition of the Lexington Herald-Leader