Noticing patches of thinning fur or bald spots on your dog’s sides can be alarming. You might run your hand along their ribs and feel bare skin where there used to be a soft coat. This kind of fur loss is surprisingly common, and the cause is often treatable. Let’s look at the most frequent reasons dogs lose hair on their flanks and what you can do about it.
Allergies Are a Top Culprit for Fur Loss on the Sides
Allergies are one of the most common triggers for hair loss on a dog’s sides. When a dog is allergic to something in their environment (like pollen, dust mites, or grass) or in their food, their skin becomes inflamed and itchy. They scratch, rub against furniture, or lick their sides obsessively. This constant irritation damages hair follicles and leads to thinning fur. You might also notice red skin, dandruff, or a musty smell. If you suspect food allergies, try a limited-ingredient diet for 8 to 12 weeks. For environmental allergies, wiping your dog’s paws and belly after walks can help. If the itching is severe, ask your vet about antihistamines or allergy testing.
Hormonal Imbalances Like Hypothyroidism or Cushing’s Disease
Hormonal issues are another major reason for symmetrical hair loss on both sides of the body. Hypothyroidism (low thyroid hormone) often causes a dull, brittle coat that thins out on the flanks, back, and tail. You might also see weight gain, lethargy, and skin infections. Cushing’s disease (hyperadrenocorticism) leads to high cortisol levels, which can cause hair loss, a pot-bellied appearance, and increased thirst and urination. Both conditions are diagnosed with blood tests and are manageable with medication. If your dog is losing fur on the sides and also seems tired or drinks more water, a vet visit is a good idea. While you’re there, you can also ask about other breed-specific health concerns, like signs of hip dysplasia in Bernese Mountain Dogs, if that applies to your pup.
“Hair loss on the sides is your dog’s way of telling you something is off inside. Listen closely.”
Pressure Points and Resting Habits Can Cause Bald Spots
Sometimes the cause is simple: your dog sleeps or rests in the same position for long periods. Large breeds, especially those with short coats, often develop calluses and hair loss on their elbows and sides where they lie down. This is called pressure alopecia. If your dog spends a lot of time on hard floors or concrete, the constant pressure can thin the fur. Providing a soft, supportive dog bed with orthopedic foam can make a big difference. For example, if you have a breed that loves to lounge, like a Bernese Mountain Dog, you might also want to check do Bernese Mountain Dogs shed a lot to understand their coat cycle better.
Dogs have three types of hair: primary (guard hairs), secondary (undercoat), and tactile (whiskers). Fur loss on the sides often affects the secondary hairs first, making the coat look patchy before the guard hairs fall out.
Parasites Like Mange or Fleas Can Cause Patchy Hair Loss
External parasites are a common but often overlooked cause. Demodectic mange (caused by Demodex mites) typically shows up as localized bald patches on the face, elbows, or sides. It’s not contagious to humans or other pets, but it can indicate an underlying immune issue. Sarcoptic mange (scabies) is highly contagious and causes intense itching, redness, and crusty skin, often starting on the ears, elbows, and sides. Flea allergy dermatitis can also lead to hair loss along the back and sides, especially near the tail. A simple skin scraping or flea check from your vet can identify the culprit. Treatment usually involves medicated shampoos, topical treatments, or oral medications.
Seasonal Shedding vs. Abnormal Hair Loss
It’s normal for dogs to shed heavily twice a year, especially in spring and fall. But if you’re seeing bare skin or thinning on the sides that doesn’t match their usual shedding pattern, it’s worth a closer look. Seasonal shedding typically happens evenly across the body, not in distinct patches. If your dog is losing fur on the sides but not elsewhere, it’s more likely an allergy, hormonal issue, or pressure point. Keep an eye on whether the skin looks healthy underneath. Redness, bumps, or flaking are red flags. If you have multiple pets at home, and you’re wondering about inter-species dynamics, you might find it helpful to read about are Norwegian Forest Cats good with dogs to ensure a harmonious household while you address your dog’s health.
When to See the Vet and What to Expect
If your dog’s fur loss on the sides lasts more than two weeks, spreads, or comes with other symptoms like scratching, weight changes, or lethargy, schedule a vet appointment. Your vet will likely do a physical exam, skin scrape, blood work, and possibly a thyroid panel. They may also recommend a hypoallergenic food trial. Avoid using over-the-counter creams or supplements without guidance, as some can worsen the problem. The good news is that most causes of fur loss on the sides are treatable, and with the right plan, your dog’s coat can grow back fully. While you’re caring for your dog, you might also be curious about other breeds in your home, so check out are Maine Coon cats good with dogs for peace of mind.
