Are rashes from poison ivy contagious?
Coming into contact with poison ivy will, for the majority of people, result in an itchy red rash. This allergic reaction is caused by the chemical “urushiol”, found in poison ivy plants. The urushiol binds to the skin and causes it to break out in a rash, itchy bumps, and even blisters and weeping sores in worse cases. A poison ivy rash is very easily contracted – all it takes is for someone to brush against a leaf of the plant, and the urushiol will immediately attach to the skin.
This is one of the main reasons for the belief that scratching a poison ivy rash can cause the rash to spread. This is a myth – scratching isn't going to spread your rash! The only way that this will happen is if you haven't washed since coming into contact with the poison ivy. In fact, you can often prevent the rash from appearing if you realise that you've touched some poison ivy, by refraining from touching the area, applying rubbing alcohol, and then rinsing and washing with warm water and soap. The reason that it's crucial not to touch the skin at this point is that the urushiol that's just been transferred from the plant to your skin will still be on the skin's surface and hopefully not yet absorbed. Touching it now would just rub it in, causing the rash to appear, and it's at this point that scratching could indeed spread the rash, since you'd basically be spreading the fresh poison over a larger area of your skin, not to mention to your hands and under your fingernails, thus transferring it to every other part of your body that you then touched!
However, once you've washed and no poison remains on your skin, scratching will not spread your posion ivy rash. Often, it can appear that it is doing just that, when you notice the rash developing in new places, but this isn't actually anything to do with your scratching. There could be a couple of explanations:
(1)When your skin comes into contact with the poison ivy plant, the urushiol oil isn't transferred in an equal layer all over your skin. Some parts of the skin will therefore come into contact with less of it than others, and the rash in these places will take a little longer to develop. But the urushiol was already there – just in a smaller quantity. You didn't transfer or spread it by scratching.
(2)Continued exposure to the poison ivy, or to something else that's been in contact with it. If the rash keeps appearing in new places, it's not because you've been spreading it by scratching. Something else has got some of that dreaded urushiol on it, and you're transferring it to your skin every time you touch it. The most likely culprit? Check your pet dog! Animals won't break out in a poison ivy rash, but if they're out and about in an area where the plant is growing, they're more than likely going to have brushed against it and transferred urushiol to their fur. So when you pat that innocent looking pooch... you get the idea.
The best thing you can do is make sure that you've destroyed the source by killing any poison ivy plants you know of, and then wash: wash yourself, wash your clothes, and wash your pets, however much they protest! If there's no more urushiol for you to come into contact with, your rash won't spread – not even by scratching.
As a side note, however, scratching is still not advisable – you'll irritate your skin and maybe even cause an infection if you scratch too deeply and break the skin!
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