The blisters and oozing result from blood vessels that develop gaps and leak fluid through the skin if the skin is cooled, the vessels constrict and leak less. If this has happened, wipe down the surfaces with bleach or a commercial urushiol removal agent. Those affected can unknowingly spread the urushiol inside the house, on phones, door knobs, couches, counters, desks, and so on, thus in fact repeatedly coming into contact with poison ivy and extending the length of time of the rash. The appearance of a spreading rash indicates that some areas received more of the poison and reacted sooner than other areas or that contamination is still occurring from contact with objects to which the original poison was spread. The fluid in the blisters is produced by the body and it is not urushiol itself. The oozing fluids released by scratching blisters do not spread the poison.
Others argue that prevention of lesions is easy if one practices effective washing, using plain soap, scrubbing with a washcloth, and rinsing three times within 2–8 hours of exposure. Ī plant-based remedy cited to counter urushiol-induced contact dermatitis is jewelweed, though jewelweed extracts had no positive effect in clinical studies. Over-the-counter products to ease itching-or simply oatmeal baths and baking soda-are now recommended by dermatologists for the treatment of poison ivy. These lesions may be treated with Calamine lotion, Burow's solution compresses, dedicated commercial poison ivy itch creams, or baths to relieve discomfort, though recent studies have shown some traditional medicines to be ineffective. Urushiol binds to the skin on contact where it causes severe itching that develops into reddish inflammation or uncoloured bumps, and then blistering. After injury, the sap leaks to the surface of the plant where the urushiol becomes a blackish lacquer after contact with oxygen. The pentadecyl catechols of the oleoresin within the sap of poison ivy and related plants causes the allergic reaction the plants produce a mixture of pentadecylcatechols, which collectively is called urushiol. Over 350,000 people are affected by urushiol annually in the United States. Typically, the rash from the urushiol oil lasts about five to twelve days, but in extreme cases it can last a month or more. Around 15 to 25 percent of people have no allergic reaction to urushiol, but most people have a greater reaction with repeated or more concentrated exposure. In extreme cases, a reaction can progress to anaphylaxis. Urushiol-induced contact dermatitis is the allergic reaction caused by poison ivy. Main article: Urushiol-induced contact dermatitis