bergamer, at some point I need to do a write up on HLLE but the truth is, it is a complex syndrom and needs to be addressed on several fronts until you find what it was causing it in your fish.
So, I haven't had time to do a write up on it yet. There have been discussion here on it. Try doing a search on Head and Lateral Line Erosion or HLLE here in the Disease Forum.
Take a look at the picture and the link on the purple tang we have posted up in the Diseased Fish Thread.