What Causes Blepharitis?

I was diagnosed with blepharitis but I cannot detect any crusting or flakes around my eyes. I had recurring eye infections, now as per advice am cleaning my eyes with diluted baby shampoo but cannot see any improvement after 2 months plus have very sore/raw corners of eyes although I ensure that I do not rub my eyes. Is the diagnosis correct and if so what else can I do to normalise the situation?