Hair Loss in Dogs: Causes, Symptoms, and Treatment

Alopecia in dogs, also known as hair loss, is a common condition that can cause bald patches or thinning of the haircoat. Unlike normal shedding, alopecia typically occurs because of an underlying medical condition.

Here’s what pet parents should know about alopecia in dogs, including symptoms, causes, treatment options, and when to contact a veterinarian.

What Is Alopecia in Dogs?

Alopecia in dogs is abnormal hair loss that causes bald patches or significant thinning of the haircoat, exposing the skin. Unlike alopecia, normal shedding occurs seasonally or year-round as part of a dog's natural hair follicle life cycle.

Alopecia occurs when an abnormality in the hair follicle interrupts the normal hair growth cycle. It can affect dogs of all breeds and ages.

Congenital vs. Acquired Alopecia in Dogs

Hair loss in dogs can be congenital (present at birth) or acquired (developing after birth in a dog with a previously normal haircoat). Alopecia can also be temporary or permanent.

With congenital alopecia, some dogs are born with a normal coat that changes over time, while others are born with hair loss.

If you notice unusual hair loss in your dog, have them examined by a veterinarian to determine the underlying cause and an appropriate treatment plan.

Most causes of hair loss in dogs are not life-threatening and are not considered veterinary emergencies.

What Are the Symptoms of Alopecia in Dogs?

Symptoms of alopecia in dogs can include localized or widespread baldness, thinning of the haircoat, itching, redness, and other skin changes. Depending on the underlying cause, some dogs may experience significant itching while others may not itch at all.

Common signs of hair loss in dogs include:

• Local or widespread baldness
• Thinning haircoat
• No itching or significant itching
• Reddened skin
• Red raised bumps (papules), pustules (pimples), plaques (flat), or hives
• Scabs or crusts on the skin
• Hyperpigmentation
• Bleeding, oozing discharge from the skin
• Ulcers or blisters
• External parasites
  • Fleas, ticks, and lice are often visible
  • Mites (mange) or fungus (ringworm) are not often visible with the naked eye
• Self-trauma (scratches, wounds)

What Causes Hair Loss in Dogs?

Hair loss, or alopecia in dogs, can be caused by many congenital (present at birth) or acquired conditions, including infections, parasites, allergies, hormonal imbalances, and other underlying health issues.

Congenital (present at birth) causes of alopecia may or may not be hereditary (genetic).

Skin Infections and Parasites

• Skin infections (bacterial or fungal)
• External parasites (fleas, ticks, lice, mites/mange such as Demodex or Sarcoptes, mosquitoes)
• Insect bites, including spiders, bees, and wasps

Allergies

• Allergies
  • Environmental (atopic dermatitis)
  • Food
  • Insect-induced allergies, such as flea allergy dermatitis (FAD)

Behavioral and Hormonal Causes

• Self-trauma from anxiety, stress, or underlying pain or discomfort
• Endocrine or hormonal imbalances
  • Cushing’s disease
  • Hypothyroidism
  • Sex hormone-related (common during pregnancy and lactation)

Autoimmune Diseases

• Autoimmune disease, such as pemphigus, discoid lupus erythematosus (DLE), or systemic lupus erythematosus (SLE)

Dog Breeds Predisposed to Alopecia

The following breeds are more likely to develop certain kinds of alopecia:

• "Bully” breeds
• Dachshunds
• Chihuahuas
• Boston Terriers
• Chesapeake Bay Retrievers
• Siberian Huskies
• Alaskan Malamutes
• German Shepherds
• Chow Chows
• Labrador Retrievers
• Poodles
• Bichon Frise
• Great Danes
• Newfoundlands
• Shetland Sheepdogs
• Portuguese Water Dogs

Other Causes of Hair Loss in Dogs

• Friction-induced, from a tight collar, harness, or clothing
• Nutritional deficiencies, such as with a poor-quality diet or starvation
• Environmental triggers (exposure to dirt, heat, and moisture)
• Chemical exposure or burns
• Radiation therapy
• Medications such as chemotherapy
• Skin cancer

How Do Veterinarians Diagnose Alopecia in Dogs?

Veterinarians diagnose the underlying cause of alopecia in dogs by reviewing the dog's medical history, performing a physical examination, and conducting diagnostic tests.

Medical History and Physical Examination

To diagnose the underlying cause of hair loss in dogs, your veterinarian will take a thorough history and perform a physical exam. During the exam, your veterinarian will look for patterns of hair loss and signs of skin infection.

They will also discuss your dog’s breed predisposition for congenital or hereditary hair loss.

Your veterinarian may also ask about:

• If your pet is on a parasite preventive
• If there are other pets in your home
• If your pet has had any environmental exposures
• How long you’ve noticed your dog’s hair loss
• If your dog has a worsening skin issue
• If your dog is itchy
• If your dog has any other health issues

Diagnostic Tests for Alopecia in Dogs

After the examination, your veterinarian may recommend diagnostic testing. Some tests provide immediate results, while others need to be sent to a laboratory.

Common tests include:

• Taking samples of the hair in or around the areas of hair loss and looking under a microscope for abnormalities of the hair follicle. This can show if hair loss is regular shedding or a medical problem.
• Skin-scrape checks for mites like demodectic and sarcoptic mange
• Cultures of the hair and skin to check for bacterial and/or fungal infections
• Black light exam for ringworm
• Skin smears or a tape prep to look for bacteria, yeast, and inflammatory cells
• Skin biopsy to diagnose autoimmune disease or cancer
• Intradermal skin testing for allergies
• A hypoallergenic or limited-ingredient diet trial for food allergies
• Blood testing for hormone levels or endocrine conditions
• Fecal analysis for parasites

How Is Alopecia in Dogs Treated?

Treatment for alopecia in dogs depends on the underlying cause and an accurate diagnosis from a veterinarian. Treatment may include medications, topical therapies, dietary changes, or other medical interventions.

Small areas of alopecia that are not itchy or bothersome might even heal on their own.

Depending on the underlying cause, alopecia in dogs may not be able to be cured and treatment can be lifelong.

Managing Symptoms Before a Diagnosis

In some cases, it can take some time to get a specific diagnosis.

In the meantime, your veterinarian will make recommendations on how to reduce the symptoms like itching and make sure your dog is comfortable, such as:

• Anti-itch, hydrating, and/or soothing shampoo
• Anti-itch spray

• Oral medications for secondary skin infections
  • Antibiotics such as cephalexin or Convenia
  • Antifungals such as ketoconazole or terbinafine
  • Anti-inflammatories such as carprofen or low-dose steroids

Treatment Options After Diagnosis

Once a specific diagnosis is made, your veterinarian will develop a detailed treatment plan that may include the treatments above or the following options.

Oral Medications and Other Medical Treatments

• Oral medications
• Steroids such as prednisone
• Allergy medications such as Apoquel, Zenrelia, or Cytopoint (injection)
• Anti-parasiticides (can be topical as well) such as flea and tick medication (such as NexGard, Bravecto, or Capstar)
• Cyclosporine (Atopica) for atopic dermatitis and immune-mediated skin conditions
• Antihistamines such as diphenhydramine can be prescribed but often don’t work very well for most dogs

• Thyroid supplementation (levothyroxine)
• Cushing’s disease treatment (trilostane or mitotane)
• Behavioral modification such as anti-anxiety medication or calming supplements, like Solliquin

Topical Treatments

• Medicated shampoo
• Medicated mousse
• Medicated wipes
• Sprays, ointments, or therapeutic dips

Dietary and Other Treatments

• Food trials (hypoallergenic, limited ingredient, or hydrolyzed food)
• Appropriate nutrition and balanced diet
• Surgical removal of tumors or growths
• Chemotherapy and/or radiation for skin cancer

Recovery and Management of Hair Loss in Dogs

Recovery from alopecia in dogs can take days to months, depending on the underlying cause. Some conditions require lifelong management.

Recovery Timeline for Hair Loss in Dogs

Superficial (surface) skin infections can be treated in seven to 14 days with the right treatment. Infections that are deep into the skin can take longer to treat.

Long-Term Management of Alopecia in Dogs

Management of alopecia in dogs is often a combination of oral medication, topical treatments, and making sure that dogs can’t lick or chew or scratch the areas of hair loss, which will slow or stop healing.

Preventing Further Skin Damage During Recovery

Using a recovery cone is key in helping prevent your dog from itching and causing self-harm or further infection.

It’s important to make sure your dog’s environment is free of triggers such as fleas and other parasites that can prolong or prevent their recovery.

How To Prevent Hair Loss in Dogs

Some causes of hair loss in dogs can be prevented through year-round parasite prevention and avoiding known triggers. However, other causes of alopecia in dogs, such as congenital or hereditary conditions, cannot be prevented.

For example, conditions like hypothyroidism, Cushing’s disease, or allergies can’t be prevented—only managed.

Acquired causes like fleas and ticks can be prevented with routine, year-round parasite prevention.

Once the underlying cause of alopecia is identified, it's important to avoid that cause in the future when possible.

If you notice areas of hair loss, have your dog examined by your veterinarian as soon as possible.

Keeping up with routine health check-ups is important to prevent an issue from becoming too severe to treat.