Can Trauma Trigger Demodectic Mange in an Older Dog?

We're glad your Sheltie survived his accident. Severe bruising and the stress of injury and recovery could play a part, but hair loss after trauma has several possible causes. Badly bruised skin can sometimes lose its blood supply and later crust, peel and lose hair. Demodectic mange can also appear when illness or stress weakens the immune system, and in a 12-year-old dog, new mange is often a sign of an underlying condition such as hypothyroidism, Cushing's disease or cancer. Your vet can tell these apart with a skin scraping and an exam, and may suggest blood tests.

One important caution: Shelties are one of the breeds that can carry the MDR1 gene mutation, which makes ivermectin potentially dangerous. Please check with your vet before the next dose and ask about MDR1 testing or a safer alternative. Ivermectin also isn't a tick preventive, so ask your vet for a tick product that's safe for him.

Please don't start antibiotics on your own, and have his tender back checked too. Crusted, tender skin needs a vet's exam so the right treatment can be chosen. Read more about demodectic mange in adult dogs.

This is general information, not a diagnosis. Please follow your own vet's advice.