Hair loss in dogs and cats, known medically as alopecia, is more than a cosmetic concern—it’s often a sign of an underlying health issue. Whether it’s due to parasites, allergies, hormonal imbalances, or behavioral disorders, hair loss should never be ignored. This guide walks you through the most common causes, how veterinarians diagnose hair loss, and what treatment options are available.

Understanding Hair Loss in Dogs and Cats

Why is my pet losing hair?
There are many potential causes for alopecia in pets, ranging from mild and treatable to more serious chronic conditions. Recognizing the early signs—like excessive scratching, red or flaky skin, or bald spots—can help you seek veterinary care promptly and avoid complications.

Expert Care at Star of Texas Veterinary Hospital

Located in Austin, Texas, Star of Texas Veterinary Hospital offers expert diagnostics and treatment plans tailored to pets experiencing hair loss. Our veterinary team provides compassionate, science-based care to uncover and treat the root cause of alopecia.

“Each pet’s skin tells a story. Our job is to listen, diagnose, and treat—so they can get back to living comfortably.”

Common Causes of Hair Loss in Pets

1. Parasites: Fleas, Mites, and More

Flea allergy dermatitis is one of the most common causes of hair loss, particularly in dogs and cats with flea sensitivities. Even a single flea bite can lead to intense itching and self-trauma.

Other parasitic culprits include:

  • Sarcoptic mange (scabies) – causes intense itching and crusty skin.
  • Demodectic mange – often affects puppies and causes patchy hair loss.

Treatment: Includes topical or oral flea preventatives, medicated shampoos, and anti-itch medications.

Read more about flea allergies in cats (Cornell Feline Health Center)

2. Allergies: Environmental or Food-Based

Environmental allergens like pollen, dust mites, or mold can cause atopic dermatitis, while food allergies often manifest through itchy skin and gastrointestinal upset.

Symptoms:

  • Red, inflamed skin
  • Frequent ear infections
  • Hair loss from licking or chewing

Explore symptoms and treatment of dog allergies (AKC)

3. Hormonal Disorders

Hormonal imbalances often manifest as symmetrical hair loss along the flanks, thinning coats, and changes in skin texture.

Common conditions:

  • Hypothyroidism (dogs): Slowed metabolism, dry skin, hair thinning
  • Cushing’s disease: Excess cortisol, pot-bellied appearance, fragile skin

Learn about the role of blood work in pets (Pet Health Network)

4. Fungal and Bacterial Infections

  • Ringworm (a misnamed fungal infection) causes circular patches of hair loss with red, flaky borders.
  • Pyoderma (bacterial skin infection) often occurs secondary to scratching or allergies.

5. Genetic Conditions

Color dilution alopecia occurs in certain breeds with dilute coat colors (e.g., Weimaraners, Dobermans). Though not life-threatening, it can cause lifelong skin care needs.

Understand color dilution alopecia (Wag!)

6. Stress-Related Hair Loss (Psychogenic Alopecia)

Excessive grooming due to anxiety or boredom can lead to bald patches, especially in indoor cats. Often seen on the belly, flanks, or legs.

Treatment: Includes behavioral therapy, environmental enrichment, and anti-anxiety medication if necessary.

7. Toxins and Environmental Factors

Exposure to chemical irritants, certain medications, or toxic plants may result in hair loss. Climate extremes can also cause seasonal alopecia in sensitive breeds.

Diagnosing Hair Loss: What to Expect at the Vet

A thorough diagnostic approach is essential for identifying the underlying cause of hair loss.

Physical Exam and Skin Tests

  • Visual inspection of the coat and skin
  • Skin scraping and cytology to check for mites, bacteria, or yeast

Lab Work and Allergy Testing

  • Blood tests for thyroid and adrenal function
  • Allergy testing (intradermal or serum-based) to identify environmental or food triggers

Advanced Diagnostics

  • Skin biopsy for chronic or unexplained cases
  • Fungal culture to diagnose ringworm

Treatment Options for Pet Hair Loss

Medications

  • Antibiotics for bacterial infections
  • Antifungals for ringworm
  • Steroids or antihistamines for allergies
  • Thyroid supplements or hormone-regulating meds for endocrine disorders

Environmental & Behavioral Modifications

  • Reduce stress with enrichment and routine
  • Proper grooming for early detection and skin maintenance

Why regular grooming matters (ASPCA)

Advanced Therapies

  • Surgical removal of cysts or tumors if needed
  • Laser therapy for healing and hair regrowth

Preventing Hair Loss in Dogs and Cats

Parasite Prevention

Year-round flea and tick prevention helps eliminate one of the leading causes of hair loss in pets.

Why parasite prevention matters (AAHA)

Balanced Nutrition

A diet rich in omega-3 fatty acids, zinc, and vitamins supports skin health and coat shine.

Routine Veterinary Care

Regular check-ups help detect early signs of allergies, parasites, and chronic conditions—before hair loss becomes severe

When to Seek Veterinary Help

Don’t Delay if You Notice:

  • Persistent scratching, licking, or biting
  • Bald spots or scabs
  • Sudden or widespread hair loss
  • Behavioral changes or signs of pain

Prompt intervention leads to faster relief and better outcomes.

Contact Star of Texas Veterinary Hospital for urgent care or a skin health consultation.

Let’s Get to the Root of the Problem

Hair loss isn’t just about appearance—it’s a window into your pet’s health. Whether the cause is medical, environmental, or behavioral, the team at Star of Texas Veterinary Hospital is here to help.

Explore our services or schedule a visit today to ensure your pet’s skin and coat stay as healthy as they are loved.