Flies are biting your dog’s ears to feed on blood. The culprit is almost always the stable fly (Stomoxys calcitrans), a species that targets the thin, exposed skin on ear tips and edges where blood vessels sit close to the surface. The condition this causes is called fly strike dermatitis, and it’s common in dogs that spend time outdoors during warm months. Left unchecked, the bites create crusted, bleeding wounds that get progressively worse as your dog scratches and shakes their head.
Why Flies Target the Ears Specifically
Stable flies are blood-feeders, and they go after areas where skin is thin and fur is sparse. Dog ears are ideal targets. The exact location of the bites depends on your dog’s ear shape. Dogs with upright, erect ears typically get bitten on the ear tips. Dogs with floppy, pendulous ears tend to get bitten along the folding edge or at the base of the ear where it meets the head. Dogs with semi-erect ears often show damage on both the front and back margins of the ear flap.
The ears also lack the thick coat that protects most of the body, giving flies easy access. Once a bite wound forms, the blood and moisture attract even more flies, creating a cycle that escalates quickly.
What Fly Strike Looks Like
The damage starts small. You’ll first notice tiny raised bumps with dark, bloody crusts at the center. These can look like small scabs or spots of dried blood on the ear edges. Some owners also notice white, flaky material around the bite sites, which is scale from skin irritation rather than dandruff.
As the bites continue day after day, those small spots progress into larger raw areas and open sores. Your dog’s natural response, scratching at the ears and shaking their head, tears the scabs open and makes everything worse. The ear tips are full of small blood vessels, and once the skin breaks down, the bleeding can be surprisingly dramatic. It’s not unusual to find sprays of blood on walls and furniture from head shaking. What started as a few fly bites can become a raw, ulcerated wound within a week or two.
Cleaning and Caring for Bitten Ears
If your dog already has crusted or bleeding ear tips, start by gently cleaning the area. Use a veterinary ear cleaning solution or a mild antiseptic wash on a cotton pad. Avoid alcohol and hydrogen peroxide, both of which irritate damaged skin and slow healing. Soak a cotton ball or pad in the cleaning solution and gently wipe the affected area, working from the inside outward. If your dog pulls away or seems to be in pain, stop and let a vet handle the initial cleaning.
Once the area is clean, applying a barrier ointment serves two purposes: it protects the raw skin from further fly access and keeps the wound moist enough to heal. Antiseptic barrier ointments designed for animals combine infection-fighting properties with a physical layer that repels insects. Petroleum jelly can work as a temporary barrier in a pinch, but it doesn’t have any antiseptic or insect-repelling properties. Ask your vet about a product that includes both wound protection and insect deterrence.
When Bites Become Infected
Repeated fly bites create open wounds, and open wounds invite bacteria. Watch for signs that the damage has gone beyond simple bite irritation: increasing redness and swelling around the wounds, discharge that looks yellow or green rather than clear, a foul smell, or skin that feels warm to the touch. Your dog may also become more agitated, pawing at the ears constantly or whimpering when the area is touched.
Severe fly strike can cause significant inflammation and intense itching that makes your dog miserable. In these cases, a vet may prescribe a short course of anti-inflammatory medication to break the itch-scratch cycle and give the skin a chance to heal. Secondary bacterial infections need targeted treatment. If the ear wounds aren’t improving after a few days of home care, or if they’re clearly getting worse, the damage has likely progressed beyond what cleaning and barrier creams can handle on their own.
Keeping Flies Away From Your Dog
Treatment only works if you also stop the flies from coming back. Prevention has two layers: protecting your dog directly and reducing the fly population around your home.
On Your Dog
Topical insect repellents formulated for dogs can be applied to the ears to deter flies. Some spot-on flea and tick treatments that contain permethrin also repel stable flies. Talk to your vet about which product suits your dog, as some ingredients safe for dogs are toxic to cats in the same household. Reapply barrier ointments to the ear edges daily during fly season, especially before your dog goes outside.
In Your Yard
Stable flies breed in decaying organic matter, and dog droppings are a major breeding site. Pick up waste from your yard daily. Compost piles, rotting vegetation, and standing water also attract flies. If your dog lives near livestock or poultry, fly populations will be much higher and harder to control without consistent waste management. Fly traps placed around kennel areas or outdoor resting spots can reduce the local population, though they won’t eliminate the problem on their own.
Timing and Shelter
Fly strike is a warm-weather problem, peaking between April and October in most climates. Stable flies are most active during daylight hours, particularly in the morning and late afternoon. Bringing your dog indoors during peak fly activity makes a significant difference, especially if your dog already has ear wounds that are attracting more flies. During warm months, check your dog’s ears at least twice a day so you can catch new bites before they escalate into larger wounds.
Dogs at Higher Risk
Any dog that spends time outdoors in warm weather can get fly strike, but some dogs are more vulnerable. Dogs with erect or semi-erect ears, like German Shepherds, have exposed ear tips that are easy targets. Dogs housed in outdoor kennels or tied in yards face prolonged exposure with no way to escape the flies. Dogs that already have ear wounds or scabs attract flies more aggressively because of the blood and moisture. Light-colored ears with less pigmentation may also be more susceptible to sun damage that thins the skin, making fly bites worse.
If your dog has had fly strike once, the scarred ear tissue is thinner and more easily damaged the next time around. Proactive prevention before fly season starts each year is far easier than treating wounds after they’ve developed.