Prevention and Treatment of Poison Ivy/Oak/Sumac
Poison ivy, poison oak, and poison sumac are the most common causes of allergic skin rashes in the United States. Poison ivy is most common east of the Rocky Mountains and usually grows as a vine. Poison oak is mort common west of the Rocky Mountains and usually grows as a shrub. Poison sumac is a shrub or small tree that grows in peat bogs or swampy areas in the eastern states and southern Canada.
All of these plants contain an oil called urushiol [you-ROO-shee-all]. Urushiol is present in most parts of the plant, including the leaves, stems, and roots. Most people in the United States will develop an allergic rash if they come into contact with urushiol by:
- Brushing against a plant that has been cut or crushed and is leaking urushiol.
- Touching something that has urushiol on it. Urushiol from a damaged plant can get on your clothing, garden tools, sporting or camping gear, or even the fur of your pet. Or you may get urushiol on your hands, then spread the urushiol to another part of your body when you touch it (for example by scratching your nose or wiping your forehead).
- Being exposed to urushiol particles in the air (for example, when someone burns any of these plants, including dead or dried plants).
However, the rash usually does not develop until after a person’s second contact with these plants.
The red, itchy, blistering rash appears within 2 days after contact. It is a myth that the fluid in the blisters can spread the rash or that the rash can spread from person to person. The blisters become crusted after a few days, and the rash usually heals completely within 10 days to 3 weeks.
The best way to prevent the allergic rash to avoid contact with poison ivy, poison oak and poison sumac. The popular saying “leaves of three, let them be” can help you to remember that the leaves of poison ivy and poison oak usually are arranged in groups of three (poison sumac leaves are arranged in groups of 7 to 13). Urushiol turns a blackish color when it is exposed to air, and damaged plants may look like they have drops of black enamel paint on them.
If you are going somewhere that these plants are known to grow, protect your skin by wearing long pants, long sleeves, boots, and gloves (vinyl gloves are best). Be very careful when you remove this clothing; don’t let it touch your skin, automobile upholstery, furniture, carpeting, or any other surface. Wash the clothing (including shoelaces) separately from other laundry with regular detergent. You should wash off any shoes, tools, or equipment that might have urushiol on them, and give your pets a bath if they have been outdoors.
Consider using Ivy Block as additional protection against urushiol. Ivy Block is a lotion that forms a protective barrier between exposed skin areas and urushiol. The lotion should be applied 15 minutes before possible contact and then reapplied every 4 hours.
If you do come into contact with urushiol, wash the exposed areas as soon as possible—preferably within 30 minutes—to prevent urushiol from being absorbed into the skin. Use soap and water, or a product formulated specially to remove urushiol (such as Tecnu Outdoor Skin Cleanser or Ivy Cleanse towelettes). Rinsing with lots of plain, cool water also works in a pinch, especially if the area is rinsed within 5 to 10 minutes of exposure. Zanfel is a wash that can remove urushiol from the skin both before and especially after the rash appears and may help provide relief from itching.
Time-honored methods for helping to relieve itching include:
- Taking tub baths with cool tap water, colloidal oatmeal (such as Aveeno Soothing Bath), or baking soda. But be careful if you use colloidal oatmeal—the tub may become very slippery!
- Applying hydrocortisone 1% cream or ointment up to four times daily. Stronger concentrations of hydrocortisone are available, but they require a doctor’s prescription.
Dabbing calamine lotion on the rash can help with itching and also help to dry oozing areas. Other products can be used as soaks or compresses to relieve itching and dry the rash; ask your pharmacist for help in selecting the product that would be best for you.
Talk with your pharmacist before using any other “anti-itch” sprays or creams. Some people have reactions to these products that can make the rash worse. If itching is making it difficult for you to sleep, a nonprescription sleep aid can be helpful.
Contact your health care provider if you are still uncomfortable despite these measures. You also should contact your health care provider immediately if the rash becomes more widespread, or if the rash affects your eyes, genitals, or large areas of your face.
