Schnauzer Scratching Behind One Ear Until It Bleeds

Scratching in one spot for a long time that heals with a collar but reopens without it suggests an itch that hasn't been explained. Common causes include an ear infection in that ear, allergies, a skin infection, mites, or a foreign body.

A fresh look from a vet, or referral to a veterinary dermatologist, is reasonable. Ask for a look inside the ear, a swab, skin scrapings for mites, and treatment of any skin infection. If the itch is allergic, controlling the allergy is what ends the cycle. Ask your vet about a better-fitting collar and medicine to control the itch while the cause is found.

See ear infections in dogs and allergies in dogs.

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