Streaming TV shows and movies directly to your home is a breeze with Netflix. As a Netflix member, you can instantly watch TV and movies on your PC, Mac, mobile device, or television. Get a free thirty day trial membership. Go to Netflix dot com slash stuff and sign up today. Welcome to brain Stuff front House, Stuff works dot com where smart happens. This podcast is brought to you by Go to Meeting, the best way to hold meetings over
the Internet readings, travel expenses, save time. Just hold an online meeting with go to Meeting. Try it free. Is it Go to meeting dot com slash brain Stuff. Hi, I'm Marshall Brain with today's question. What causes poison ivy blisters? The rash that you get from poison ivy is caused by a chemical in this sap called urushial. This chemical penetrates the outer layer of skin until it hits the dermists,
and in the dermist an allergic reaction occurs. From that definition, there are a number of things that you can deduce about poison ivy. First of all, not all people get poison ivy. If your body doesn't mount an allergic reaction, then you can swim in poison ivy and it will have no effect. It turns out, however, that the majority of people's immune systems react to this chemical after several exposures. Second, you can't get poison ivy unless you come in contact
with the SAP that contains rushial. However, it is incredibly easy to come in contact with that sap. You can get it from the plants itself. You can get it from touching your shoes or pants if they have rubbed against poison ivy plants. You can get it from your dogs or your cats fir if they walk through poison ivy. The rushi all has to penetrate the skin to get to the dermist, so thin skin will show symptoms before thick skin will. And finally, rushill does not spread through
the body. The blisters that form are not contagious. They don't contain any more of the chemical. If you come in contact with poison ivy, washing off the SAP will limit your reaction to it, but you have to wash it off before any significant penetration occurs. The mechanism that causes the itching and swelling is a complex immune response to the chemical, as in any allergic reaction. What's happening is that your body's immune system is overreacting to the chemical.
It mounts a huge defense to the arushial, which causes all the swelling and inflammation in the skins. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com. This episode of brain Stuff is brought to you by Linda dot Com. Linda dot com offers thousands of engaging, easy to follow video tutorials taught by industry experts help you
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