Dog with demodex mites?

Well first of all if your dog was already on a monthly regiment of frontline then you should not be applying another flea and tick application, you can easily overdose and poison the dog. Frontline plus has been used to treat demodex and has been known to work very well. You can also ask your vet about using a medicated shampoo such as mitaban, which is specifically designed to help with the treatment of demodex and sarcoptic mange. If the dog is flaring up again i would take her back to the vet and have a skin scraping performed to make sure that it is still the demodex and not some other sort of mange such as sarcoptic mange. Demodex is harder to treat in older dogs so it may take longer then usual treatment. The last option i have seen for the treatment of demodex is interceptor ( yes the monthly heartworm prevenative) when used daily for a period of time it has shown to work wonders with demodex.. but the cost adds up very quickly. Your best bet would be to go back to the vet for a follow up skin scraping, ivermectin treatment, and a mitaban dip, then a follow up skin scraping to make sure the mites are under control. Most vets also would be recommending a blood panel be performed to make sure the immune system isn't being compromised as that will delay the treatment even more. Good luck though!!