A dog losing hair is one of the most common signs of dermatological disease in canines. A dog losing hair is medically termed alopecia.

The signs of dog hair loss are areas of uneven fur coverage or patches of bald spots. 

The treatment for a dog losing hair depends on the underlying cause. Commonly prescribed medications are antibiotics, antiparasitics, thyroid hormone supplementation, zinc supplementation, anti-itching medication, and omega fatty acids. 

What is Hair Loss in Dogs?

Hair loss in dogs or alopecia is the complete or partial loss or thinning of hair across a dog’s body. Hair loss or alopecia is caused by various dermatological conditions affecting the skin. 

Parasitic infections, allergies, autoimmune diseases, dietary insufficiency, and endocrine diseases are among the most common causes of alopecia in dogs. 

Alopecia is partial or generalized depending on the causative agent. Visible lesions accompanying alopecia include redness, scaling, crusting, lichenification, hyperpigmentation, and itchiness. 

What are the Common Causes of a Dog Losing Hair?

The common causes of a dog losing hair are listed below.

• Mange: Mange is a dermatological condition caused by mites such as Demodex, Sarcoptes, and Cheyletiella. Presented as patterns of alopecia, redness, and excoriation on the face, elbows, and body. The mite's burrowing action causes intense pruritus and alopecia on parts of the body. 

• Allergic dermatitis: Allergic dermatitis is when the skin experiences hypersensitivity signs such as redness, itching, and hair loss. Common allergens in dogs are pollen, food proteins, medications, and parasites. 

• Hypothyroidism: The thyroid hormones T3 and T4 are important in completing the phases of hair development. A lack of thyroid hormone causes symmetrical thinning of the fur around the trunk and legs, which is noticeable on the right and left sides of the body. 

• Cushing’s disease: Cushing’s disease or hyperadrenocorticism is the abnormally high production of ACTH or adrenocorticotropic hormone. ACTH stimulates the production of cortisol, which affects the cyclic regulation of the hair follicle, leading to hair loss. 

• Pyoderma: Itchy dogs are more likely to develop pyotraumatic dermatitis.

Is Dog Hair Loss Genetic?

Yes, dog hair loss is genetic. Some dogs are affected by hereditary issues such as Alopecia X, alopecia areata, and certain non-inflammatory follicular dysplasias. 

Certain breeds, such as Doberman Pinschers and Dachshunds, are predisposed to hair loss. The hair loss pattern is symmetrical and unresponsive to commonly used hair loss support. Dogs affected with genetic hair loss have structural differences in the hair follicles that affect their growth. 

Is Dog Hair Loss Caused by Allergies?

Yes, dog hair loss is caused by allergies. Mild allergies cause redness, itching, and swelling. Dog allergies include flea allergic dermatitis and food hypersensitivity, which cause generalized alopecia.

Itching from alopecia can lead to further traumatic hair loss due to persistent scratching and friction. The cause of any specific type of dog allergy is not well established but is believed to be hereditary. 

How do Vets Spot the signs of Hair Loss in Dogs?

Vets spot the signs of hair loss in dogs by a historical examination, skin scraping, using a Wood’s lamp, culture testing, biopsy, and hematology.

A historical examination analyzing the onset and duration of hair loss in dogs is important for supporting the cause. The veterinarian uses the information to assess possible exposure to allergens such as smoke, aerosols, or any other substance that the dog has been exposed to which are able to cause allergic hair loss. 

Skin scraping is the microscopic evaluation of the skin cells to determine if parasitic mites are causing skin problems. A scalpel blade scrapes a small portion of the skin's surface, and the sample is mounted on a glass slide. Mange is definitively spotted when adult mites or mite eggs are present in the sample. 

A Wood’s lamp is a handy tool for identifying species of fungi that cause skin issues. Microsporum canis is a fungal species of pathologic importance in dogs. The fungi fluoresce under the wood’s lamp, which is usually where patches of bald and circular-shaped marks are located. 

Culture testing involves petri plates containing agar for growing pathogenic bacteria or fungi that are used to support dog skin issues. Hair or skin samples are placed inside and incubated for several days to let the pathogens grow. The resulting sample is tested for identification and susceptibility to medication.

Biopsy identifies non-resolving alopecia, which could be a sign of skin cancer in dogs. The biopsy process involves taking a small portion of skin tissue and examining the cellular makeup.

Hematology or a blood evaluation determines endocrine issues such as hypothyroidism or Cushing’s Disease. A blood sample is taken and processed to determine the amount of T3 and T4 in the blood. Cushing’s Disease is spotted using an ACTH stimulation test or a low-dose dexamethasone suppression test. 

What are Supportive Care Options for Dog Hair Loss?

The supportive care options for dog hair loss are listed below.

• Antibiotics: Bacteria such as the Staphylococcus species are commensal organisms. Commonly used antibiotics are amoxicillin or amoxicillin-clavulanate, clindamycin, cephalexin, and topical ointments with mupirocin or silver sulfadiazine. 

• Antiparasitics: Mange is usually prescribed with antiparasitic medication that effectively kills the mites inhabiting the skin. The medication works for at least 30 days to prevent and kill existing mites and end their life cycle. Commonly used antiparasitic medications for mites are isoxazolines and avermectins. 

• Antifungals: Dermatophytosis is usually prescribed with antifungal agents. Ringworm and Malassezia dermatitis are common in dogs and are treated with medication, immunostimulation, and topical therapy. Antifungal shampoos are prescribed with oral medication and triazole antifungals such as itraconazole or fluconazole. 

• Mineral Supplementation: Zinc and copper are important minerals affecting dog coat health. Some dogs have mineral-deficient dermatoses due to inadequate amounts of dietary copper and zinc, leading to dull and epilating fur. Daily supplementation is prescribed to dogs affected to restore proper copper and zinc levels. 

• Hormone Supplementation: Dogs with Cushing’s Disease or hypothyroidism require supplementation of the lacking hormones. Cushing’s Disease is managed with cortisol-reducing drugs such as trilostane. Hypothyroidism is usually prescribed a synthetic thyroid hormone called levothyroxine. 

What Can You Do To Support Dog Hair Loss Caused by Food Allergies?

You can do a food elimination trial for dog hair loss caused by allergies. The first step to supporting food allergies is identifying the allergen causing the problem and avoiding exposure. A veterinarian guides pet owners in conducting a diet trial in which hypoallergenic food is exclusively fed to the dog for at least 8 weeks. 

A new food source is introduced to monitor signs of allergic response once the allergic signs disappear. The food is considered safe when no signs of allergic reaction occur within 2 weeks. 

Allergy testing for food allergies in dogs involves sedating the dog, shaving a side of the body, and exposing it to multiple allergens. Hematological allergy testing is available but is a more expensive form of determining allergies. A limited-ingredient diet is suitable for dogs with prolonged allergies.

What Can You Do for Dog Hair Loss Caused by Fleas?

You can use regular anti-tick and flea-preventative products for dog hair loss caused by fleas. Dog flea allergies are highly manageable with proactive products and environmental control. 

Apply anti-tick and flea oral or spot-on medication to all household dogs to support every dog. The medication is effective for 30-90 days and is available over the counter. 

Clean the dog’s bedding regularly with mild disinfectant soap to destroy the shed flea eggs. Clothes, carriers, collars, and cages require a thorough cleaning. 

Topical therapy with anti-tick and flea shampoos helps refresh the skin and deter fleas from coming close to the dog’s body. 

Consult a veterinarian for a specific dog flea allergy plan and flea-control plan for each dog’s needs. 

Consult a veterinarian if seeking specific brand recommendations.

Can Ringworm in Dogs Cause Hair Loss?

Yes, ringworm can cause hair loss in dogs. Ringworm causes circular patches of flaky alopecia. The fungi Microsporum and Trichophyton are the causative agents of hair loss caused by dermatophytosis in dogs. The dermatophyte invades hair follicles and causes hair to fall out. The fungi feed on the keratin found in hair and skin, which causes alopecia or ringworm in dogs.