10 Causes for Your Dog Losing Hair Under Their Armits

There is a reason why we call dogs our fur buddies. Their luscious hair is one of the reasons why we love these remarkable animals. So, of course, we cannot stomach the thought of anything damaging our pet’s coats. Yet, hair loss occurs more than you know in dogs, and in most cases, it is not a terrible thing.

Let’s face it- of all the places to notice hair loss in your dog, the armpit is a pretty weird spot. But that is what makes you an excellent pet owner- your amazing skills of observation. If your dog is losing hair under his armpits and you want to know what is going on, keep reading.

Hair loss in dogs can be as simple as the process of shedding or a sign that your dog is battling a medical concern. In this article, we will walk you through all you need to know about such hair loss in dogs and what you can do to fix it. So, keep reading.

10 Possible Causes for Dog Armpit Hair Loss

Here are the various reasons why your dog could be suffering from underarm bald spots.


Hair loss could be a sign of an allergic reaction in your fur buddy. Like us, our pets can have an immune reaction to anything. Food, insect bites, parasites, and pollen are common causes of such reactions in dogs. Besides hair loss, you might notice itching in the affected area under the arms.

Parasitic infection

Different ectoparasites like fleas, ticks, mites, and lice can cause your dog’s hair to fall out. Most of these parasites favor dark and moist areas of the body (like the armpits) as their dwelling site. Flea allergy, dermatitis, and mange are ectoparasitic diseases that have hair loss as one of their symptoms.

Fungal infections

Although fungal infections are not as popular as bacterial infections, they still cause a nuisance for dogs. You will observe significant hair loss in a pet suffering from a ringworm infection. Ringworm is contagious and affects the hair, skin, and nails. The most popular symptoms include circular or random hair loss and infected crusts.


Balding isn’t only a genetic issue in humans. Some dog breeds, like Chihuahuas, Dachshunds, and Greyhounds, are more prone to having bald spots after their first year. You may see these bald spots on thighs, armpits, ears, and low on their limbs. If your dog is a short-haired breed, this hair loss may be due to his genes.

Senior Dog Hair Loss

Geriatric dogs lose hair as they age and often have bald spots. One of the first places to go bald is the armpit because the hair there is little. In most cases, it is due to hormonal issues, dry skin, or nutritional deficiencies. In the event of hormonal causes, you might notice excessive weight gain or weight loss.

Bacterial infection

Most of us are familiar with parasitic skin infections like mange and ringworm. Bacterial skin infections are not as popular, but they occur and can cause damage to your pet’s hair and skin. Most times, these infections cause the skin to itch. When your dog itches that area again and again (the armpit in this case), hair starts to fall out.

Post grooming alopecia

For double-coated dog breeds like the Akita, Chow Chow, and Siberian Husky, any form of clipping (like in surgery prep) can cause hair patches to form. This issue will resolve itself in a matter of months. So, if your pooch was shaved or incised in the armpit region recently, this could be the cause of his abrupt hair loss.

Hormonal imbalances

Hypothyroidism, sex hormone disorders, and Cushing’s disease are conditions associated with the imbalance of certain body hormones. Hormones are important chemical mediators in the body that help the body function. Symmetrical hair loss is a symptom of the diseases listed above.

Injury, rashes, and hives

If your dog got bitten in his armpit region, a body reaction could cause hives or rashes to develop in that area. This, in turn, will lead to hair loss in that area.

Exposure to chemical irritants

Certain chemicals can irritate and even damage the skin, leading to hair loss. Chemicals can also cause hives and rashes to form in affected areas. This is why you should keep toxins away from your dog’s reach.

9 Things to Do for Dog Armpit Hair Loss

The best way to solve hair loss issues in dogs is the find out its cause. We have discussed the common causes of bald spots in the armpits. Now, let us see how you can help your dog out of this sticky situation.

Get your pet to the vet.

A veterinarian is skilled in differentiating normal occurrences from abnormal ones. In the case of allergies or hormonal imbalances, the doctor will need to examine and treat your canine. By looking at the pattern of hair loss, examining the symptoms, and carrying out the right tests, the vet will find out the cause of this hair loss and start necessary treatment.

Examine your pooch for other symptoms

Hair loss may come with other symptoms like itchiness, a fever, bad odor, irritated skin, or skin lesions. These symptoms are sometimes clues to finding out the cause of baldness.

Feed your canine companion with a good diet

Nutritious foods promote healthy skin and hair growth. Hair loss may be a sign of malnutrition. The better the quality of food given, the healthier your pet will be. It could be that your pet is lacking a few essential nutrients.

Use tick and flea preventives

These preventives include dermatologically approved shampoos, topical medications, flea collars, powders, and others. You might also need to treat with antibiotics to combat secondary bacterial infections. Also, treat any insect bites you notice.

Keep up with regular grooming practices

Regular grooming is great for dogs. It is a combination of brushing, nail clipping, and bathing, depending on the dog’s breed. Regular grooming helps you spot any skin issues and helps spread natural body oils.

Use a dietary supplement

Dietary supplements containing omega-3 fatty acids are a great way to improve general coat health. These supplements not only prevent the occurrence of skin health issues, but they also help in its treatment by creating a skin barrier.

Routine deworming

Depending on your pet’s age, he will need to be dewormed at different frequencies. Contact your veterinarian if you are unsure when and how to deworm your little guy.

Isolate your pet from other pets

If you suspect that your dog has ectoparasites, keep him away from other dogs. By isolating your pet, you limit the spread of these parasites to other animals.

Wait it out

If your dog is shedding, there is nothing you can do to stop it. Usually, this shedding period lasts for two to three weeks. During this time, keep up with healthy feeding and routine maintenance. 

Can This Problem Go Away on Its Own?

Depending on its cause, loss of hair in the armpits may or may not go away on its own. In cases like post-grooming alopecia and shedding, you can be sure that all will be well after some time. Yet, with most of the causes of bald spots, your pet needs some form of treatment before hair starts to regrow. In a case where aging causes hair loss, there is no remedy.

After ascertaining the cause of hair loss, your veterinarian will inform you about the right treatment methods. These methods could include oral and topical medications, shampoos, dietary changes, and allergy shots. Your pet will undergo many tests to diagnose his condition.

If this hair loss is caused by shedding, it will go away on its own in a matter of weeks. While some dog breeds shed more than others, it is a natural process for every dog. You cannot keep your dog from shedding; you can only wait till the shedding passes. Shed hair will soon regrow.


If your dog is losing hair from under his armpits, don’t be dismayed. Chances are this is a normal shedding process that will wrap up in two to three weeks. If the hair loss seems excessive or your pooch is showing other symptoms, contact your veterinarian immediately.


  • Brad

    Hi I'm Brad, the founder of bulldogpapa.com. Having been a vet of 6 years I work alongside our team to provide valuable insight into your dog's health. I have a frenchie myself named Senzu who is my pride and joy!