One: try looking into whether or not you have body lice, mites, etc.http://www.getridofthings.com/forums/topic/biting-insects-driving-me-crazy
Two: the ML protocol might be of value (system too acidic)
Three: try cutting back on sweets and simple sugars
Four: if you're taking supplements that hinder or block needed nutrients from being absorbed by your body, that might be a causitive factor- try playing with eliminating one at a time, or using a different combination of supplements (sometimes more is less)