Poison Ivy
Poison ivy allergy is an acquired trait which can only develop after contacting the oleoresin of poison ivy. This problem can affect 70% of the population of the U.S. After initial exposure it takes 4 – 10 days to develop an allergy, but once a person is allergic to poison ivy it takes only 24 – 48 hours after contact to break out in a rash. Some persons become sensitized after the first exposure, but others may suddenly become sensitized after numerous previous non-reactive exposures.
Poison ivy is a plant which may appear as a vine, or as a low growing or upright plant. The leaflets grow in groups of three. The oleoresin is in the leaves, stems, seeds, flowers, berries and roots. It may be carried in particulate matter in the smoke of burning plants.
Can I wash it off?
The oleoresin penetrates skin very rapidly. Washing with soap and water within the first 5 to 10 minutes may prevent an eruption. Washing within 30 minutes may lessen the eruption. When washing, pay particular attention to fingernails. The resin can stay on the surface of clothes, shoes, blankets, car seats, tools, baseball bats, golf clubs and pets. These items should be washed to prevent further exposure. Use plastic gloves to handle contaminated items.
The Rash (dermatitis)
The eruption usually starts within 2 days, but rarely is delayed as long as 7 to 10 days. The resin persists in the skin about 3 weeks from the time of exposure. Poison ivy rash is usually characterized by redness, swelling and blisters. The blisters are often in a line. The rash usually breaks out on thinner skin first and then gradually shows up in other areas. The palms are rarely infected because the skin is so thick. However, resin on the palms and fingers is easily transferred to other body areas, including the eyelids and genitalia.
The fluid in the blisters does not contain any oleoresin and does not cause spreading of the rash on the body. This is a common misconception. New lesions may continue to appear as a natural part of the allergic process in areas where the resin touched the skin initially. Poison ivy dermatitis can not be spread from one person to another by touching the skin, blisters or blister fluid.
Treatment
Treatment for poison ivy is designed to give symptomatic relief until the rash subsides, usually about 3 weeks. Mild soaps (i.e. Basis, Dove, Aveeno) should be used for bathing. If you have access to a tub, you might try oatmeal (i.e. Aveeno) baths for relief of itching. Cool water compresses relieve itching and help reduce blisters. Calamine lotion (plain calamine, not with additives) also helps relieve itching and dries up blisters. Blistered areas should be left open to the air as much as possible. Antihistamines by mouth relieve itching as well. Chlorpheniramine and Benadryl can be purchased and used according to directions without a prescription. Antihistamines cause drowsiness and when taking them, you should not drive or operate machinery. Antihistamines should not be applied to the skin. If lesions are extensive, on the face or swelling is severe, seek the help of a health care provider.
Cross Reactions
Sensitivity to poison ivy cross-reacts with other closely related plants. These include:
– Poison oak
– Poison sumac (this grows in bogs only)
– Mango – especially the rind of the fruit
– Japanese lacquer tree – only in the Far East
– Cashew nut oil – only raw nuts
– Indian marking nut – used as laundry marking ink
– Gingko trees – especially the fruits
– Indian water – buffalo hides sandals – these are tanned with a chemical that cross reacts with the oleoresin
The rash (dermatitis) caused by contact with these plants is the same as poison ivy dermatitis.
Prevention
There is no successful recommended way to be desensitized to poison ivy. The best protection is to learn what it looks like and avoid it! When in wooded areas, wear socks, long pants and sleeves as much as possible. You may wish to try various over-the-counter products to protect against poison ivy. It should be applied prior to going into wooded areas.
Source: www.uhs.wisc.edu