If there are tiny blisters that burst when you scratch, it is probably poison ivy. Caladryl Lotion
http://www.familymeds.com/familymeds/product.asp?sku=30071318119 (the pink lotion) works best. It takes about two weeks to cure the poison ivy and you have to keep applying the lotion. You can also take benydryl to stop the itching. Benydryl will cause drowsiness so most people take it before going to sleep.
It could be some type of fungus but it looks like poison ivy.
