You want to try putting vinegar on your own open wounds before you put it on the poor  dog - it hurts a lot.  that is very cruel and crueler to suggest someone else puts it on. You shuld be called atomic.  Don't you like dogs? 
purple julie buy some  
STOP ITCH or 
QUIT ITCH  
from the petstore or produce. It is an iodine based treatment which is antiseptic, anti fungal and antibacterial and for open wounds  If it is a fungal thing this will fix it, and unlike straight iodeine it wont make the hair fall out.   
No vinegar, wonder atomic  was not bit.