Getting out into the yard after a long winter can be exciting and invigorating but also a lot of work. With a wet spring, weeds and vines have grown amuck, so clearing these areas is often a top priority. But keep in mind that there may be poison ivy, poison oak or sumac lurking with the more benign shrubs.
Poison ivy runs rampant in the eastern US. Poison oak is most often found in the south as well as rural west. Poison sumac, fortunately is rare, but can be just as troublesome. Annually, these plants account for 50 million cases of rash in the US alone.
The cause of the rashes associated with these plants is the oil on the plant itself, urushiol. When this oil comes in contact with the skin, it binds to proteins on the skin cell surface causing them to change shape and appear “foreign” to the body’s immune system. This ignites a cascade of immune reaction leading to the red, blistery, itchy and painful eruption of contact dermatitis. In approximately 15-30% of people, urushiol does not elicit an immune response. However, at least 25% of the population has very strong reactions to it, usually leading to severe symptoms. Often a person must be “sensitized” to urushiol. The first few times the skin comes in contact with the oil, little may happen, but subsequent exposures will lead to progressively stronger reactions. Thus it is safe to say, one can definitely become allergic to these plants at any point in their lifetime.
Contact dermatitis will typically develop within 24 hours of contact with the plant. While we commonly think of these rashes as summer time phenomena, urushiol is present in every part of the plant at ANY given time throughout the year. It also can remain active on non-living objects for years! So cleaning all clothing, shoes, socks, gardening tools, camping equipment, etc. that has been exposed is critical to preventing further exposure and subsequent rashes. Even pets need to be washed as urushiol on their fur can be deposited on skin prompting an outbreak.
The typical eruption can last anywhere from 2-5 weeks. The majority are mild in nature and will resolve spontaneously in 14 days. However, infection can be a major complication as scratching brings bacteria to breed in broken, susceptible skin. This will usually require a prescription antibiotic to resolve. Treatment of contact dermatitis can be thought of in two phases: stopping the urushiol contact with the skin and treating/reducing the pain and itching of the ensuing eruption.
To prevent urushiol from binding, exposed skin must be washed with soap and cool water within minutes of exposure. Since it is an oil, soap is required. Commercial preparations are also available containing surfactants that bind to urushiol solubilizing it and washing it away. The FDA has also approved an over the counter product that contains a clay like ingredient. When used before potential contact with urushiol, it acts as a barrier to prevent binding to the skin.
Once the rash is present, treatment consists of topical steroid creams and antihistamines to soothe redness and itching. If a reaction is severe enough, a 2-3 week course of oral prednisone from your medical provider may be necessary. The best treatment of all is prevention through avoidance of any suspicious plant or vine.
Remember urushiol is what causes the rash, so once it is washed away from the skin, you cannot “give” poison ivy to someone else. Scratching the rash itself does not spread it, as the rash is being driven by your internal immune reaction. Scratching can, however increase your chances of having a secondary infection, so seek treatments to help prevent continual scratching. Also keep in mind that burning the vines and plants may aresolize the urushiol which for those who are highly sensitive may result in contact with the oil from the smoke and possibly even inhalation leading to a greater systemic reaction.
As common as contact dermatitis is, it doesn’t have to keep you from the outdoor activities you love. Familiarize yourself with the appearance of these plants, avoid them even if you don’t think you’re allergic, and if you do have contact, try to wash the oil from your skin as soon as possible. If you do break out, seek treatment to prevent unnecessary infection and speed resolution.
