- It's natural for dogs to shed hair, especially in spring and fall — and some shed more than others.
- But a thinning coat or bald patches may suggest a dietary imbalance, parasite, or skin condition.
- It's best to take your dog to the vet if they also have itchy, swollen, red, or irritated skin.
If your dog is a heavy shedder, you're probably used to living in a perpetual fur-nado — especially during shedding season in spring and early fall.
But while seasonal shedding is normal for many breeds, thinning hair or bald patches could point to a skin condition.
Hair loss — aka alopecia — isn't usually an emergency situation, according to Dr. Joanna Woodnutt, veterinarian and author at Love Your Dog. However, hair loss could still make your dog feel itchy and uncomfortable — not to mention impact their natural coat.
Here's the good news though: Many causes of canine hair loss are treatable. So, a trip to the vet could help you uncover the root cause of their issue.
Read on for five potential explanations for hair loss in dogs below, plus tips from vets to handle your dog's thinning hair.
1. They have an allergy
If your dog's skin is red or irritated, this often points to inflammation caused by an allergy, says Dr. David Israel, veterinarian and medical director at the Veterinary Emergency Group.
Allergic dermatitis — skin allergies, in other words — could cause your pup to scratch or lick at their skin and lose their fur. What's more, all the biting or scratching could leave your dog's irritated skin open to infections, Israel says.
What to do next: Before you can treat your dog's skin allergy, you'll need to know what caused it.
Common allergies that may cause skin irritations in dogs include:
- Flea bites: Some dogs are allergic to flea saliva, which could make their skin red or scabbed. Getting your dog regular flea and tick treatments could help them stop scratching and find relief.
- Environment allergens: Dust, pollen, and mold spores can all cause your dog to itch. Environmental allergies are often seasonal, so you may notice your dog only losing fur at certain times of the year — like during pollen season in the spring. Limiting your dog's time spent outdoors or using allergy medication may help manage your pup's symptoms.
- Food: Some dogs may lose fur if they're allergic to an ingredient in their food. Switching your dog to a different diet might help them avoid potential allergens and feel less itchy. Your vet can help you narrow down possible allergy triggers.
2. Their diet isn't balanced
Beyond food allergies, a nutritional deficiency in your dog's diet could lead to hair loss, Woodnutt says.
For example, hair growth uses around 25%-30% of your dog's daily protein requirement. So, a diet low in protein could slow down hair growth or stop new growth altogether.
Additionally, omega-3 fatty acids support the health of your dog's skin and coat. However, many commercial dog foods don't contain enough omega-3s, which could leave your dog open to deficiencies.
What to do next: "Changing your dog's diet to one higher in omega fatty acids may reduce fur loss, or you can get nutritional supplements to add to your dog's usual food that may help," Woodnutt says.
Just keep in mind that it's always best to get a green light from your vet before switching your dog's food or adding a dietary supplement.
3. They have an endocrine disorder
If your dog is losing fur, but their skin isn't red or irritated, they may have an underlying endocrine disease or hormonal issue, Israel says.
Endocrine diseases that could lead to hair loss in dogs include:
- Hypothyroidism: This occurs when your dog's thyroid gland becomes inflamed or shrinks and doesn't produce enough thyroid hormones.
- Cushing's disease: With Cushing's disease, your dog might have a tumor on their pituitary or adrenal gland, which could cause their brain to release too much cortisol — aka the stress hormone.
- Alopecia x: Sometimes, an overproduction of adrenal sex hormones could lead to hair loss. This disorder, also called alopecia x, more commonly affects certain breeds, including Pomeranians, Siberian huskies, and Samoyeds.
What to do next: Dogs with hormone deficiencies often respond well to treatments that replace the missing hormone.
Depending on your dog's particular condition, your vet may recommend hormone replacement therapy with medication.
4. They have a skin parasite
If your dog has a skin parasite, like mange, they may feel itchy and scratch or bite at their skin — which could lead them to lose their hair.
One type of mange, called canine scabies, can easily spread from dog to dog. Symptoms usually appear around eight to 10 days after your dog comes into contact with an infected dog.
Beyond itching or losing their hair, a dog with mange may also experience other symptoms, including:
- Crusty skin
- Rashes
- Bacterial or yeast infections
What to do next: To treat mange, your vet may recommend topical or oral medications or bathing your dog with skin-soothing shampoo.
5. They have an autoimmune disease
Alopecia areata is an autoimmune disorder that causes hair loss in humans. Dogs can also get a form of alopecia areata, which may lead to thinning hair or bald patches.
With alopecia areata, your dog's coat may thin slowly over time — mainly around areas like their ears, beck, chest, thighs, or stomach. Unlike other skin conditions, however, alopecia areata doesn't typically cause itchiness or irritation.
Alopecia areata can affect any dog. But some breeds are especially prone to this condition, including:
- Daschunds
- Miniature pinschers
- Boston terriers
- Whippets
- Italian greyhounds
- Chihuahuas
What to do next: There's no cure for alopecia areata in humans or dogs.
However, your dog can go into remission, and some of their hair may grow back. According to one study of dogs with alopecia areata, hair grew back for 60% of the canine participants within just a few months of their initial diagnosis.
Some evidence has also linked certain medications, like cyclosporine, to potential hair regrowth.
Is it hair loss or shedding?
If your dog normally sheds like an out-of-season Christmas tree, it can be tough to know if their hair loss warrants a trip to the vet.
But, in general, seasonal shedding doesn't lead to thinning or bald spots, Israel says. Even if your dog regularly sheds enough hair to make a whole new dog, their coat should still look full and shiny.
"I always suggest having a professional take a look if your dog is shedding more than usual, has bald patches, or is shedding out of season," Woodnutt says.
According to Israel, you should also make a vet appointment if your dog's hair loss coincides with other symptoms, such as:
- Red or discolored skin
- Swelling
- Discharge
- A change in weight or appetite
Insider's takeaway
Shedding is a fact of life for many dogs. But if you notice bald patches or thinning hair, this could mean your dog has an underlying health issue, like an allergy, nutritional deficiency, or hormone disorder.
A trip to the vet could shed a light on the cause of your dog's hair loss — and potentially help them manage their pup-pattern baldness.
Brooke Helton is a freelance health and wellness writer with a passion for holistic living. She's a contributing writer for Insider and loves empowering others to take charge of their lifestyles. When she's not writing about herself in the third person, you can find Brooke lurking on LinkedIn or getting lost in the Appalachian countryside.
