Is it possible this reoccurring rash is a poison ivy/oak rash caused by contact with a contaminated item? I know a woman who had a poison ivy rash that would go away and come back for months. Turns out she was getting the rash from an item of clothing that had the Urushiol on it still. Regular washing of the item did not remove the oil from the clothing item and she would get the rash every time she wore it.