I am usually pretty careful about avoiding poison ivy habitats at all seasons.  But the last time I erred, I discovered a wonderful dual product that (a) will prevent blisters from developing or (2) if the blisters have developed, will relieve the itching and dry the blisters within a few days.  

It is called Tecnu (the preventive)/Calagel (the curative).  I bought it at the Rite-Aid in Williston.  

http://www.teclabsinc.com/products.cfm?id=7088BA7C-AACE-1250-5B5229985B8E7AE4

I now carry a small bottle of Tecnu in my pack at all times.

Carol Wagner
North Williston