Dog Hair Loss: Causes and When to Worry

By Tailwisp Editorial TeamUpdated October 17, 20263 min read

Seeing bald patches can be worrying. The cause may be simple, or it may point to a bigger issue.

Normal shedding versus alopecia

Dogs shed seasonally and constantly to varying degrees. Normal shedding does not create bald spots. Alopecia means thinning or bare skin. See excessive shedding in dogs.

Common causes

• Allergies. See dog skin allergies
• Fleas. See flea allergy dermatitis in dogs
• Mange. See mange in dogs
• Ringworm. See ringworm in dogs
• Bacterial or yeast infection. See pyoderma in dogs and yeast infections in dogs
• Hormonal disease. See hypothyroidism in dogs and Cushing's disease in dogs
• Friction or pressure, such as from collars
• Genetic hair loss in some breeds
• Medication reactions
• Post-surgical or injection-site changes
• Stress-related licking or chewing

Patterns that help

• Symmetrical, non-itchy hair loss on the flanks often suggests hormonal disease.
• Patchy, moth-eaten loss with crusts may indicate infection or mange.
• Loss at the tail base suggests fleas.
• Loss around the eyes and muzzle may point to demodex or allergies.
• Bald ear tips can be from sun, sarcoptic mange or genetics.

Diagnosis

Your vet will examine the skin, ask about itch, diet and medications and may perform:

1. Skin scrapings and cytology
2. Fungal culture
3. Flea checks
4. Blood and urine tests for hormones and organ function
5. Biopsies in difficult cases

Treatment

Treatment targets the cause: parasite control, antifungal or antibiotic therapy, allergy management or hormone replacement. Do not use human hair products or supplements without advice.

Hair regrowth

Hair often returns weeks to months after treatment. Some conditions leave permanent changes. Your vet will discuss expectations.

Seasonal and breed-related loss

Some breeds, such as Alaskan malamutes, have blowing coat cycles. Others, such as Chinese crested dogs, are naturally hairless. Pattern baldness occurs in some breeds, such as dachshunds and Italian greyhounds. See hairless dog skin care guide.

Stress and behavior

Excessive licking or chewing can remove hair. See compulsive behavior in dogs. Rule out medical causes first.

When to see a vet

Book a visit if hair loss is sudden, widespread, itchy, accompanied by redness, smell, lethargy, weight change or increased thirst.

Common mistakes

• Waiting months.
• Switching foods repeatedly.
• Using home remedies.
• Assuming it is stress.

Troubleshooting

• Hair loss is symmetrical: ask about hormone testing.
• Hair loss spreads fast: call your vet.
• My dog licks one spot: check for pain or allergies.

A simple plan

1. Note the pattern.
2. Book an exam.
3. Test as advised.
4. Treat the cause.

Real-life examples

A boxer with flank hair loss is diagnosed with hypothyroidism and regrows hair on treatment. A terrier with bald patches around the eyes has demodex. A husky's heavy shedding is normal and managed with brushing. Pattern and tests tell the story.

Documenting changes

Take photos weekly to track progress.

Preparing for the appointment

Photograph the affected areas, list recent changes in food, shampoo or medication, note how your dog behaves and bring a list of parasite products used. The more detail you give, the faster your vet can narrow down causes and save you extra tests.

Hair cycle basics

Hair grows in cycles, and illness, stress, pregnancy or surgery can push many follicles into a resting phase at once. A few weeks later, hair falls out in clumps. This type of shedding often regrows on its own, but it is still worth mentioning to your vet to rule out other problems.

The takeaway

Hair loss has many causes. Note patterns and see your vet for testing.

This article is general educational information, not veterinary advice. Every dog is different. If your dog is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.