My mother is a nurse and as child, admonished me for scratching at my poison ivy as it would spread.
That never made sense to me. I asked her once, how MY BODY produces the fluid inside the blister that was "spreading" by scratching it, yet...if left unscratched and the fluid was already INSIDE my body, I had no reaction to it.
I got a look. /w3tcompact/icons/eyes.gif
None the less, my understanding & belief is that when one comes into contact with poison ivy, one gets various degrees of exposure. Some take longer to appear than stronger doses, and as such, may give look of "spreading".
I have never, and continue to not belive that AFTER all "exposure areas" are cleaned of the poison ivy oil, that by scratching alone, you can spread it.
I once (recently) had a NASTY bout of it on my forearm..blisters on TOP of blisters... In Walmart once, I accidently banged same forearm on something and looked like I popped a hydraulic line... the blisters popped and spread all over my arm... I did NOT get a BIT of NEW poison ivy from this. I had FAR more exposure to this "fluid" than ANY plant I could have come in contact with AND was unable to get home to clean it up for maybe an hour or so.
Anyway, not to argue, not to incite... I think that the spreading of PI is somewhat a wives tale told for maybe good reason...(prevent scarring?) I just believe my OWN eyes and experience.
Some reading, surely to bore someone!! /w3tcompact/icons/grin.gif
<A target="_blank" HREF=http://poisonivy.aesir.com/faq.html>http://poisonivy.aesir.com/faq.html</A>
An exerpt:
Can I spread it by Scratching?
"Rhus plants(poison ivy, poison oak, poison sumac) are the most common cause of allergic contact dermatitis in the US. Rhus plans contain the potent antigen urushiol, which will sensitize 60% to 80% of the persons who are exposed to it. ...(It) may be carried on the fur of pets, clothing, shoes, toys, tools, or other objects and then transferred to the skin. Approximately 24 to 36 hrs after a sensitized person is exposed to the urushiol, a blistery, itching rash develops. Usually within 15 minutes of contact, the urushiol binds to skin proteins. If it is washed off with soap and water before that time, a reaction may be prevented. After the antigen is fixed, however, it cannot be washed off or transferred to other areas. Scratching or oozing blister fluid cannot spread the antigen to other areas of the body or to other persons. New lesions that appear a few days after the primary lesions represent less sensitive areas or areas where less antigen was deposited, not spreading of the antigen. Because the course of the reaction usually is 12 to 15 days, 2 weeks of medication should be prescribed. Reference [Dermatology in Primary Care 1994]
Once bound to cell membranes, urushiol is virtually impossible to wash off and attached to cell membranes becomes a "warning flag" that attracts patrolling T-cells and initiates a full-blown immune response. Reference [Herbalgram (American Botanical Council) Volume 34: 36-42, 1995 by W.P. Armstrong and W.L. Epstein, M.D.]
Bold highlight added by me.