Poison Ivy (Toxicodendron radicans) is a poisonous plant that is very common in North America, particularly in New England. Coming in contact with poison ivy is not enough to acquire its harmful effects - the plant must be torn or broken which causes a clear sap-like liquid to come out of it known as urushiol.
Urushiol (pronounced: oo-roo shee-oll) is an oily organic allergen found in posion ivy, oak and sumac that causes a rash (contact dermatitis) upon getting it on your skin. Urushiol is so potent that it can produce outbreak in hundreds of people with as little as the amount on the head of a pin. Because of this potency it is absolutely crucial you get the oil off your skin as soon after exposure as possible, preferably within 15 minutes, as this is the minimum amount of time the urushiol needs to bind to the proteins in your skin. You most certainly should flush it from your skin within an hour of making contact with it. If washed off within this window you stand a very good chance of avoiding a reaction. Sweating or not rinsing your skin well enough will only result in the urushiol being spread across your skin, so be sure to irrigate excessively.
Use cold water as hot waters opens your pores, allowing the urushiol to soak into your skin even quicker. After the urushiol binds to your skin it cannot be washed off or transferred to other parts of your body, even though this is a popular myth.
Once the urushiol sets you can expect to see a reaction in about 24 to 36 hours, but people with first-time exposure can take as long as 7 to 10 days to see their reaction. Even if you've never had poison ivy or believe you are immune to it, you still run the risk of getting it with every contact. This is because you sensitize to urushiol the more you are exposed to it. Instead of building a tolerance, you build an in-tolerance to it, meaning you get it easier and quicker with every new exposure. Of course this is not an absolute, as there are always exceptions. Some people truly are immune to urushiol oils, but is this something you are willing to rely on? Once you get your reaction you can expect to see it start with a severe itching of the skin, of course, which is then followed by red inflammation and blistering of the skin. More severe cases will manifest with oozing sores.
Another common myth about poison ivy is that it can spread from these oozing sores. Not true. You may be dealing with new blisters appearing in places they hadn’t been before, seemingly out of nowhere, but the reality of the situation is that these are areas of your skin that either are less sensitive to the urushiol or they simply didn’t get as high a dose of it so it took longer to develop. Of course it could also be caused by new exposure from clothing, shoes, tools, fur of pets or other objects that still have the urushiol oils on them. This is why it is so important to not only cleanse your skin but any items or clothing that may have come into contact with the poison ivy as a result of you being where you were. Another reason to cleanse objects and items: urushiol oil can actually retain its potency for up to 5 years. This includes dead plants that have been chopped down or uprooted, so don't think that just because it's dead that it’s hamless.
So now that you’re a itchy, burning, gooey mess what do you do? How can you expect to find any relief? Well, it should go without saying that a severe case (you will have to be the judge) will require expert medical consultation. If you are highly allergic – your rash will develop in as little as 4 to 6 hours – you should also seek medical attention. For those of you who aren’t highly allergic and are willing to suffer all on your own there are a number of over-the-counter options available which include, but aren’t limited to: Zanfel, Tecnu, Antivy, RhuliGel, Ivy Dry, Caladryl Clear, Burt’s Bees Poison Ivy Soap, Ivy Off, Ivarest, Ivy Block, Lanacane, even good old-fashioned Calamine lotion, the list goes on and on. What you need to keep in mind is some of these products are used to cleanse the urushiol from the skin immediately after exposure while others are designed to treat the itch from the rash.
The itching you experience is caused by the buildup of histamine in the skin cells, at the site of the rash. Histamine is a neurotransmitter involved in local immune inflammatory responses that gets released in larger amounts during an allergic reaction, such as to exposure to urushiol. The histamine is meant to have two effects: vasodilation and fluid secretion. Vasodilation is when your blood vessels in the affected area relax, thus expanding, to allow white blood cells to move more quickly to the site of the rash. Fluid secretion is meant to rid the body of infectious agents and allergens; a sort of flushing of the system. The latter of these is highly evident in high doses of urushiol where you get those oozing blisters mentioned earlier. Because of the high levels of itching caused by the increases in histamine buildup a good histamine blocker, or antihistamine, such as Benadryl can help bring relief.
Another method of itch relief involves the use of hot water. Hot water has the same effect as antihistamine because heat causes the histamine in the cells to break up and dissipate. Use water as hot as you can stand on the back of your hand (in the range of 120 to 130 degrees Fahrenheit is sufficient) and either soak or run water on your skin until the itch dissipates. Histamine released in this manner takes several hours to regenerate, which can bring you anywhere from 4 to 8 hours of much-needed relief. This is a fantastic remedy to use just before bed to help ensure an descent (itch-free!) night's sleep.
Now that you are able to treat the itch and get relief, all that remains at this point is to dry up any open sores and blisters. Some people again turn to the many commercial products available, while others turn to more readily available household means such as vinegar, salt, baking soda and lemon juice or even bleach!. You can also use a lotion containing calamine, zinc acetate or alcohol, all of which will dry out the rash and speed up the healing process. I prefer isopropyl alchohol (91%). It can sting pretty badly, but it gets in there and helps dry things up quickly.
Time will tell how long it will take for your "creeping crud" to go away, but it should start to clear up in anywhere from one to several weeks, depending on your level of tolerance. Most reports indicate 3 or 4 weeks as a good baseline for total recovery from poison ivy. Good luck!