Why do dogs lose hair?

Animals typically lose hair a couple of times a year—during the spring and fall shedding periods. This is a normal seasonal phenomenon that requires no intervention. However, if this period is still some time away and the coat is noticeably thinning and shedding rapidly, the owner should be concerned about the pet's health. Seasonal shedding also doesn't cause changes in the dog's behavior or well-being, and exposure to other factors is often accompanied by loss of appetite, lethargy, and scratching of bald patches. In such cases, it's important to determine the underlying causes and take appropriate measures to address them.

Causes of hair loss

A veterinarian can determine why a dog is losing hair after examining the animal and conducting the necessary tests. If your pet's hair has thinned rapidly or bald spots have formed, it's time to consult a specialist, as this could be a symptom of a serious condition that can only be treated with medication.

There are two main groups of causes of hair loss:

• hormonal nature - changes in the functioning of the body caused by disruption of individual glands;
• non-hormonal - disorders caused by other, usually external, factors.

When hormonal levels change, baldness occurs symmetrically throughout the body, whereas an asymmetrical, chaotic distribution of bald spots indicates other diseases not associated with hormonal imbalances.

Hormonal disorders

The most common hormonal causes of unscheduled shedding include:

• Excess cortisol (Cushing's syndrome) – in addition to baldness, it is accompanied by intense thirst and profuse urination, frequent infectious diseases, swelling and sagging of the abdomen.
• Growth hormone deficiency – usually manifests itself during puberty in male dogs as the formation of symmetrical bald spots on different parts of the body.

The breeds most susceptible to this hormonal disorder are considered to be Chow Chows, Boxers, Poodles, Pomeranians and Airedale Terriers.

• Excess estrogen is accompanied by hair loss in the genital area in females and swelling of the foreskin in males.
• Estrogen deficiency – most common in spayed middle-aged females – initially causes slow hair growth in the genital area and subsequently in other areas of the body. Existing hair thins, and the skin becomes very soft and delicate.
• A disruption in the production of thyroid hormones (hypothyroidism) causes brittle and dry fur and bald spots on the neck, chest, back, and other areas, along with lethargy and apathy, a sharp increase in body weight, and decreased resistance to infection.

Non-hormonal causes

If your dog's hormonal balance is normal, other causes of excessive hair loss should be investigated. Among the most common options are:

• Allergic reactions are also accompanied by irritation and scratching of the skin, and reddened eyes. They can be caused by food, household cleaning products (used for grooming the dog or cleaning the apartment), or seasonal allergens.

Important: Animals fed natural food experience allergic reactions much less frequently than those fed prepared dry food.

• A weakened immune system can persist after serious illnesses, so it's important to support your pet's health during this period with additional vitamin and mineral supplements.
• Zinc deficiency causes dry, rough, bald skin, flaking, and cracking of the soft pads on a dog's paws.
• Incorrect grooming: Avoid using human shampoos or excessively hot water when bathing pets. Long-haired pets are recommended to be given a full bath once a month, and wire-haired pets even less frequently. Regular brushing is essential.

Frequent bathing causes the washing away of the fatty substances that form a protective layer on the dog's skin, resulting in a deterioration in the quality of the coat, which becomes drier and thinner.

• Fleas and other parasites - the dog behaves restlessly and scratches their bites, which is accompanied by significant thinning of the coat.
• Dandruff (seborrhea) - can also cause hair loss in the most affected areas or be a secondary sign of the disease (eczema, dermatitis, diabetes mellitus, etc.).

• Stress and anxiety – often the occurrence or prolonged exposure to stressful factors brings suffering to the pet and can cause partial or complete baldness.

Toy breeds are especially susceptible to stress. For example, Chihuahuas can become nervous due to vigorous play and loud noises. To relieve stress, provide them with quiet, restful rest, limit alone time, and avoid harsh handling.

• Scabies – caused by the presence of tiny scabies mites and accompanied by itching, the dog's hair falls out in patches. Initially, small patches of hair loss are observed around the eyes and corners of the mouth. However, if left untreated, the bald spots merge, forming a continuous bald patch, and pyoderma (a bacterial infection) may develop.
• Mutation alopecia (Blue Doberman syndrome) is characterized by widespread hair loss across all areas of the body, with pustules and papules forming. Visually, the animal appears to have been moth-eaten.
• Yeast infections most often develop in areas of increased moisture (such as the armpits, skin folds, or areas between the toes) and are accompanied by an unpleasant odor and excessive oiliness in the affected areas.

Breeds with wrinkled skin and a large number of folds on the body, such as Shar Pei and Bulldogs, are most susceptible to this type of infection.

• Solar dermatitis – characterized primarily by facial baldness, can also cause ulcers and the development of autoimmune problems.
• Sebaceous adenitis causes symmetrical baldness on the head, neck and back of the animal and may be accompanied by an infectious lesion of the hair follicles.

Treatment

There's no universal cure for alopecia. Hair loss can be triggered by a number of factors, so treatment depends entirely on the source of the problem. If alarming symptoms appear, pet owners should consult a veterinarian to examine the dog, assess the condition of the coat, conduct the necessary tests, and identify the cause of the hair loss. Diagnosing the cause at home is not only ineffective but also unsafe, as hair loss can be not only a harmless allergic reaction but also a symptom of a disease that poses a threat not only to the pet but also to family members.ringworm, scabies).

Depending on the examination results and symptoms, the doctor will prescribe the necessary treatment:

• For hormonal imbalances, specialized medications to stabilize hormonal levels, such as Trilostane and Metatonin, are most often prescribed. If recovery is not achieved within 6 weeks, medications should be reviewed.
• For fungal infections, topical lotions and ointments containing ketoconazole, miconazole, or clotrimazole are used. For systemic treatment of pathogens, griseovulfin (or itraconazole) is used, along with additional vaccines to accelerate healing and suppress fungal activity.
• For parasite infestations, shampoos, topical drops, sprays, injectables, and collars are effective. These can include products specifically designed to eliminate a single parasite, or comprehensive treatments that guarantee elimination of ticks, fleas, and worms (such as Stronghold or Bars drops, Inspector, Frontline, and Beaphar sprays).
• Dandruff is effectively treated with special shampoos that not only remove flakes but also soothe irritation and regulate sebum production. These include Stop-Doctor with birch tar and GlobalVet.

Each treatment option can be supplemented with vitamin and mineral complexes, fish oil, and other medications to strengthen the immune system.

By taking preventative measures, most hair loss problems can be avoided altogether. To do this, ensure your pet has a balanced diet and proper grooming, keep up-to-date on vaccinations and antiparasitic treatments, and regularly inspect your dog's body after walks.

You can also ask our website's staff veterinarian a question, who will answer them as quickly as possible in the comments box below.

Read also:

• Dandruff in dogs
• Doctor shampoo for dogs
• Allergies in dogs: symptoms and treatment