Is your dog losing hair in patches and showing unusual symptoms? Is this normal shedding or a sign of an underlying disease? This article will help pet owners determine whether excessive hair loss in dogs is caused by nutritional deficiencies, hormonal disorders, skin fungus, or parasites. From there, you can choose the appropriate treatment and care plan to help your dog quickly regain its smooth, healthy coat.
Distinguishing normal shedding from pathological hair loss
Normal shedding is the process of removing old hair to make way for new hair that suits the weather or each stage of a dog’s development. Some signs include:
- The skin remains pink and healthy, with no signs of redness, blisters, or dandruff-like flakes.
- Hair falls out evenly over the body or more heavily in areas with a thick double coat.
- New hair is already sprouting in the area where the hair just fell out.
- The dog continues eating and sleeping normally, without itching, scratching, or licking one spot repeatedly.
Normal shedding usually occurs most strongly in spring and autumn. In female dogs, it can also occur after giving birth or during heat.
Pathological hair loss is a sign that the dog’s body is experiencing a health problem. The skin often shows abnormal signs such as:
- Swollen, red skin, sores, or pustules.
- Many dandruff-like flakes, dry peeling skin, or darkened skin.
- An unusual foul odor on the skin.
- Hair falling out in patches, with clearly bald areas.
The dog will often scratch, rub against walls, or lick and chew the hair-loss area due to itching or burning pain.
Why is my dog losing a lot of hair? Causes and signs
Nutritional deficiencies
A deficiency in essential nutrients is often the root cause of a dull, brittle coat that sheds easily in dogs.
- Zinc: Zinc plays an important role in cell division and protein synthesis. Dogs with zinc deficiency often have diets too high in grains containing phytates, which interfere with absorption, and may show thickened skin with hard crusts around the eyes, mouth, and paw pads.
- Biotin (Vitamin B7) and Keratin: Biotin helps support the synthesis of keratin, the main structural component of hair. When biotin is deficient, the epidermis loses elasticity, the dog’s hair becomes brittle, loses pigment, and falls out in large patches.
Cushing’s syndrome
Cushing’s syndrome (hyperadrenocorticism) occurs when the body produces excessive cortisol. Cortisol is a stress hormone; when present at high levels for a long time, it weakens the immune system and causes thin, darkened skin, symmetrical hair loss, a pot-bellied appearance, and increased drinking and urination.
The disease causes a dog’s hair to grow slowly or not at all. The skin gradually turns black or dark gray and becomes noticeably thickened.
Hypothyroidism
Hypothyroidism is a deficiency of the thyroid hormones T3 and T4, causing all metabolic processes in the dog’s body to slow down. Dogs with hypothyroidism mainly develop the condition due to two major causes: autoimmune thyroiditis and idiopathic thyroid atrophy. This disease is commonly seen in dogs aged 4 to 10 years, especially large breeds.
- Autoimmune thyroiditis: The dog’s immune system treats the thyroid gland as a foreign body and attacks it, causing inflammation and destruction of the glandular follicles.
- Idiopathic thyroid atrophy: Normal thyroid tissue shrinks and is replaced by fatty tissue, no longer able to produce enough hormones.
- Genetic factors: The disease tends to be inherited and is often seen in breeds such as Golden Retriever, Doberman Pinscher, Irish Setter, and Cocker Spaniel.
This disease causes the dog’s hair to become dry, brittle, and fall out in patchy, symmetrical areas on both sides of the flanks or neck without itching. Symptoms are often accompanied by dry skin or dermatitis.
Demodex mange in dogs
Demodex mange only flares up when a dog’s immune system is weakened by stress or an underlying condition. It is rarely contagious among healthy adult dogs. Demodex mange is commonly seen in puppies or dogs with weak immune systems, such as elderly or sick dogs.
The initial hair-loss patches often surround the eye area, forming a “spectacle” pattern, or appear at the corners of the mouth and on the dog’s front legs. The disease rarely causes itching in the early stages. The dog’s skin may become darkened or ooze discharge if present. This discharge is usually caused by a secondary skin infection.
Sarcoptic mange in dogs
Unlike Demodex, Sarcoptes is a parasite that spreads quickly from dog to dog and can be transmitted to humans. The mite burrows deep under the epidermis to lay eggs, causing severe allergy and inflammation in dogs.
The disease causes intense itching along with hair loss. Dogs will scratch, bite, and lick continuously until the skin becomes abraded and bleeds. Sarcoptic mange often appears on the edges of the ears, elbows, hocks, and belly. When the edge of a dog’s ear is gently rubbed, the hind leg will show an involuntary scratching response, which is a suggestive sign of the disease.
Ringworm dermatitis in dogs
Ringworm (dermatophytes) is a disease caused by filamentous fungi. These fungi usually attack the keratin in hair and nails. When dogs dig in soil or come into contact with fungal spores from the environment or other animals, the fungus can easily take root and spread outward in a circular pattern. This is a contagious disease that can spread from animals to humans.
Dogs with this fungal infection often develop round red spots, scaling, and patchy hair loss. The circular hair-loss patches in dogs usually have clear borders and look like coins. The center of the patch often has white scales or is slightly red, while the outer edge may be inflamed. The hair shafts in the affected area are often brittle and break close to the root.
Yeast dermatitis in dogs
Unlike ringworm, yeast (Malassezia dermatitis) is a fungus that normally lives on the skin of healthy dogs. The disease occurs when this fungus multiplies rapidly due to high humidity or underlying conditions such as allergies or hormonal disorders.
The fungus Malassezia pachydermatis often causes hair loss and severe itching in dogs. The dog may have a strong sour smell or the odor of damp socks, even right after a bath. The skin may become thick and dark, resembling elephant skin. This fungus often localizes in skin folds, between the toes, under the belly, and especially causes chronic otitis externa with dark brown, sticky ear discharge in dogs.
How to treat hair loss in dogs
Nutritional supplementation
An unbalanced diet will make a dog’s hair follicles weak and prone to breakage and shedding. Owners should supplement:
- Fatty acids: Add fish oil (Omega-3 and Omega-6) to the dog’s diet to nourish the skin’s lipid barrier and keep the coat shiny.
- Minerals and vitamins: Especially zinc, biotin (Vitamin B7), and Vitamin E. These nutrients help regenerate the epidermis and the structure of the dog’s hair shafts.
- High-quality protein: Hair is mainly made of keratin. Make sure the dog eats quality meat rather than only starches or common filler ingredients.
- Switching foods: If you are using cheap kibble, consider switching to premium formulas with specialized skin and coat support.
Veterinary examination
In cases where the dog has a hormonal disorder, its health should be monitored regularly because hormonal treatment often lasts a lifetime. This requires intervention from a veterinarian.
- Blood and urine tests: This is a mandatory step to determine hormone levels. Owners cannot self-treat at home with ordinary medications.
- Hypothyroidism: Daily supplementation with synthetic thyroid hormone.
- Cushing’s syndrome: Use medication to suppress cortisol production or surgical intervention if there is an adrenal tumor.
In addition, if your dog shows the following signs, you should take it to the vet to prevent the condition from worsening:
- Large patches of hair loss, bald spots.
- Red skin, rash, scaling, or a foul odor.
- Severe itching, frequent scratching.
- Dull, unhealthy coat all over the body, continuous shedding that does not stop.
Parasite control
When infected with parasites, dogs will lose hair and itch. Owners should refer to the following treatment methods and must not use human topical or oral medications on dogs without guidance:
- Use specific medications: Oral drugs in the Isoxazoline class (such as ETO Modex with Afoxolaner, Bravecto with Fluralaner, etc.) are often highly effective in killing ticks, fleas, and mites such as Sarcoptes and Demodex.
- Clean the environment: Spray parasite-killing products where the dog sleeps, and wash bedding with hot water to prevent reinfection.
- Treat secondary dermatitis: If the dog’s skin has pustules or sores from scratching, antibiotics or anti-inflammatory topical medications may be needed as prescribed by a veterinarian.
For dogs with fungal dermatitis, you should:
- Antifungal medication: Use topical medications containing ketoconazole or miconazole. In severe or widespread cases, oral medication such as itraconazole should be used along with medicated baths as directed by a veterinarian.
- Shave the affected area: The fur around the fungal lesion should be shaved to help the topical medication penetrate better and to prevent pathogens from remaining on healthy fur.
- Keep dry: Fungi thrive in moist environments. Dry the coat thoroughly after bathing and keep the dog’s living area well ventilated.
FAQs
Can excessive hair loss in dogs spread to humans?
Most common causes of hair loss in dogs are not dangerous to human health, including normal shedding, nutritional deficiencies, and hormonal disorders.
If the dog’s hair loss is caused by skin fungus, parasites (Demodex, Sarcoptes), fleas, or lice, owners should be especially careful because these can be transmitted to humans.
How should you handle a dog losing hair due to disease so it does not spread to humans?
In addition to medication, owners should pay attention to the following to avoid infection:
- Set up a temporary isolation area: Keep the dog in a designated area and stop close contact activities during treatment.
- Personal protection when caring for the dog: Use medical gloves, wear a separate light jacket when handling the dog, and disinfect your hands after contact.
- Environmental hygiene: Clean the floor daily with specialized solutions, disinfect the dog’s items with hot water above 60°C, and dry them in sunlight.
Is dermatitis with hair loss in dogs serious?
When a dog has dermatitis, it will often scratch, lick, or bite the affected area to relieve discomfort. This causes open wounds, pus, and skin necrosis. If left untreated for a long time, chronic dermatitis will cause prolonged stress and weakness in the dog.
Owners should treat this condition thoroughly with specialized topical, bathing, and oral medications, or through veterinary examination to help the pet recover and maintain good health.
Can hair loss caused by mange in dogs be cured?
Hair loss caused by mange in dogs can be completely cured if the correct type of mange is identified and treated according to the proper protocol. Owners can refer to available products on the market containing Isoxazoline active ingredients such as Afoxolaner, Fluralaner, Sarolaner, and Lotilaner.
In Vietnam, Afoxolaner is commonly found in parasite-chew products such as ETO Modex, Nexgard.... Its affordable price and proven safety record have made it widely used in veterinary facilities nationwide.
Conclusion
Hair loss in dogs not only affects appearance but also reflects the dog’s health status. Whether caused by nutritional deficiencies, skin fungus, or parasites, early detection and treatment of the underlying cause will help the pet recover effectively.
A nutritious diet and regular deworming should be maintained for dogs. If hair loss is accompanied by signs of lethargy or widespread sores, take your dog to a veterinarian immediately for a thorough examination.
