You sound like you have a strongyle infection , I have been fighting this for over a year and I am 98 percent better. Has your vet done a strongyle test on your dog , or other parasite stool tests . Do you see spider web like threads , do you have an itchy rectum , itchy feet , sand like stuff from scalp and butt. Strongyles are the ones that burrow thru hair causing split ends and falling out. Do you have white film on skin where active areas are , you can wipe these areas with a black cloth to confirm . If this makes sense to you maybe I can guide you to better health.