Why Is My Dog Losing Hair and What Should I Do? A Vet’s Guide


The appearance of a dog losing hair usually distresses the owner more than the pet. A bald spot on a dog may be nothing, or it can signal a problem.

There are many causes of a dog’s hair falling out. These include allergies, parasites, hereditary factors, or disease. Also, the problems that are most common differ depending on the dog’s age.

Indeed, hair loss is only a symptom. Finding the underlying cause is key to targeted treatment and a return to a full, fluffy fur coat.

This article explains some of the causes of alopecia in dogs, the importance of diagnosis, and some ways to stop your dog losing hair.

Can Alopecia in Dogs Affect any Age Group?
Yes, although some problems are more common at certain ages.

For example, puppies are prone to parasitic infections or skin infections which cause hair to drop out. A puppy’s weak immune system may struggle to control infections that an adult dog would see off.

One reason for adult dogs’ fur falling out is a heavy shed. With adults also prone to allergies and seasonal alopecia.

This is in contrast to an older dog with no hair that may have an underlying health problem, such as hypothyroidism or Cushing’s disease.

To understand alopecia in dogs, know how canine fur grows. Each hair has a finite lifespan, after which it falls out of the follicle and sheds. When the rate of hair loss is faster than dog hair growth this results in bald patches.

Getting to the root cause means answering two questions: Why is the dog hair falling out and why isn’t it re-growing fast enough?

Answer these questions and you’re best placed to tackle the causes of hair loss in dogs.

A Heavy Shed or True Alopecia in Dogs?
First decide if your dog losing fur is due to a problem or if it’s just a heavy shed.

When molting, hair comes out easily from all over the coat. The latter remains plush with no skin soreness or rawness, and no bald spot on the dog.

If the dog is otherwise well, try brushing daily for a couple of weeks. Then you’ll get on top of the problem of the dog losing hair and the shedding should ease.

However, what’s not normal is a dog losing patches of hair, especially if the skin is sore or there’s no regrowth. Other tell-tale signs of trouble include dog hair loss and itching, dog hair falling out in clumps, and patchy hair loss with scabs.

Remember, a dog losing hair is just a symptom. Help your vet reach a diagnosis by considering the clues.

Good questions to think through are:

Is the dog losing hair in patches and scabs, or more generally over the body?
Is the dog itchy or not?
Are other pets in the house affected?
Has the dog had a problem with hair loss in the past, and if so, when?
Does the dog have other symptoms such as thirst, lack of energy, or weight loss or gain?

This helps the vet decide if the problem is infectious, seasonal, or a complication of ill health.

The Causes of Hair Loss in Dogs
Taking a broad overview, some of the causes of hair loss in dogs include:

Hereditary hair loss
Although this is generally uncommon, the Pomeranian breed is suffers from a form of genetic hair loss called Alopecia X. In this case the ‘X’ means no-one knows the cause.

Allergic Dermatitis
This is due to allergens in the environment or a food allergy. Itchy skin is a common symptom and it’s the excessive scratching or licking which leads to dog hair falling out.

Folliculitis
Infection around the hair shaft, beneath the skin’s surface, damages the follicle and causes hair to fall out.

This can be a bacterial infection (from muddy or dirty skin) or a fungal infection such as ringworm. The latter causes a circular bald spot on the dog.

Hot Spots
These are areas of skin that are infected and have a sticky discharge. Like folliculitis, this damages the hair shaft causing hairs to fall out.

Parasites, including Mange
Fleas, lice, and mange mites all cause dog hair loss and itching.

One form of mange, Demodex, is known as ‘red mange,’ as the bald spots become inflamed and sore. Demodectic mange often occurs in puppies, as their weak immune systems can’t fight off the mites hiding in the hair follicles.

Underlying Health Problems
A dog losing fur who has other symptoms may well have an underlying health problem. Conditions such as underactive thyroid glands (hypothyroidism) and Cushing’s disease come with complications such as hair loss and bald patches.

These dogs usually have other symptoms such as thirst, changes in appetite and weight, and lack of energy.

Seasonal Alopecia in Dogs
Seasonal alopecia is typified by a dog losing patches of hair in a symmetrical pattern on both sides of the body.

This condition can be unsightly but is of no deeper significance than too many hair shafts entering a resting phase at the same time. The fur usually regrows when the season changes.

Diagnosis: Why is Your Dog Losing Hair?

Some problems are instantly recognizable, but others aren’t always that simple.

The vet examines the dog, takes a history, and forms a problem list in their head. Then they decide which tests are most helpful. It may be necessary to run:

Diagnostic blood tests: Looking for exposure to certain parasites or overreaction to allergens in the environment
Skin scrapes: To identify parasites
Cytology: Examining the cells present on the skin’s surface
Skin biopsy and histology: Looking inside the skin cells
Screening blood tests: For health problems
The answer to one or more of these tests gives the reason behind the dog losing hair.

Treating Alopecia in Dogs
As you now know, dog hair loss treatment depends on finding the driving cause. Do this and restoring your dog’s coat becomes easier.

Alleviating Allergies
An itchy allergy is uncomfortable for the dog, whose licking and scratching creates bald patches.
Allergies can’t be cured but can be controlled.

In an ideal world the dog avoids the allergen, but if this is something like grass then it’s impractical. In this case, taking lots of small actions, all of which make a little difference, adds up to a more comfortable dog.

For example, regularly bathing the dog with a moisturizing shampoo washes allergens from the skin’s surface. Feeding a diet rich in Omega 3&6 strengthens the skin from the inside out.

Keep the skin’s surface healthy by controlling natural yeast populations. Simply wiping the dog’s paws with an antifungal wipe can reduce the tingle and licking.

Then there’s medication. There’s a whole spectrum of effective anti-itch medications ranging from old favorites such as steroids to sophisticated modern drugs like oclacitinib (Apoquel).

Indeed, the newest treatment isn’t a drug at all, but a biological therapy that deactivates the itch pathway in the body, removing the signal to scratch.

Preventing Parasites
Even the thought of fleas or ticks makes us itchy.

Regular use of an effective anti-parasite product is common sense. But you should treat all pets in the house, not just the dog losing fur. This stops the dog’s pet pals acting as reservoirs of infection.

Also, be sure your chosen product works against the particular parasite your dog has. Many products are broad spectrum, but may not work against an unusual or uncommon parasite.

Beating Bacteria
Whether it’s folliculitis, mud rash, or a hot spot, bacteria have a lot to answer for. Medicated washes help spruce up the skin. An antibiotic gel, or even tablets, is required to tackle a more deep-seated infection.

Helping Hypothyroidism
When an underlying health problem is found, such as underactive thyroid glands, the answer is to treat this problem. It may be that a simple daily tablet is all that’s needed to sort out that bald dog.

The Outlook for Alopecia in Dogs
Happily, for a dog losing hair the outlook is usually rosy (or hairy!) Correct the triggering problem and their coat should plush up again.

Of course there are exceptions. For example a bald dog that’s a Pomeranian may well have Alopecia X, a condition for which there’s not recognized treatment. For these little guys, keeping the skin in good condition and wearing a woolly in winter is the best compromise.

Prevent your Dog Losing Hair
There are a few simple rules that help your hound have a healthy coat.

These include:

Feeding a good diet rich in vitamins, antioxidants, and omega oils.
Keep the skin clean and supple with a moisturizing shampoo
Regular use of an effective anti-parasite product
Seeking veterinary help when the dog is itchy and scratchy
Daily grooming to improve skin circulation and spread natural oils over the coat
Do these things and a dog losing hair should be a thing of the past. And if it isn’t: Visit the vet.