Hair Loss Related to Endocrine Dysfunction in Dogs

Shedding is normal in dogs; some shed more than others.  However, a dog’s fur coat should not be thin enough for you to clearly see his skin and should not have bald patches where his coat should be thick and plush.  If your dog’s coat sounds like this description, it may be a result of an endocrine imbalance.  The only way to determine if it is an endocrine dysfunction is through diagnostic blood work.  

Once diagnosed, proper medical therapies and medications can be prescribed and started.  Given time, the medications will return your dog’s endocrine levels to normal and therefore his hormonal levels within his body will return to normal.  This will allow for the body to return to normal functions, including growing new fur.

If your dog is experiencing fur loss for no apparent reason, he may be suffering from an endocrine related medical condition.  If you have noticed your dog’s fur thinning or that he is balding, it is recommended you take him to his veterinarian for an evaluation.

Symptoms may include: 

• Hair loss (symmetrical, asymmetrical, typically begins in areas of friction, then is seen on other places of the body)
• Hair loss may be seen with or without scratching, licking
• Additional symptoms will vary depending on the primary cause of your dog’s fur loss

Types

Hair loss on the body due to endocrine dysfunction can occur anywhere.  Owners typically begin to notice fur loss at places of friction.  This means the neck under the collar and the caudal thighs typically experience hair loss first.  The thinning then begins to move its way up and down the body.  It can be one sided fur loss, but with endocrine dysfunction, hair loss seen is typically symmetrical.

Hyperthyroidism, hypothyroidism, Cushing’s disease, and Addison’s disease are the most common endocrine dysfunction disorders that cause hair loss in dogs.  If the endocrine gland does not excrete the proper amount of hormone, it typically results in some degree of hair loss.  The body tries to compensate, but is unable to due to the imbalance.

When you arrive at the veterinarian’s office, she will start by collecting a history from you as a part of her diagnostic process.  She will want to know when you first noticed your dog was losing his fur, if and where he has been scratching or licking excessively, if you have fed him anything new lately, if he has had any changes in his routine or home that could cause stress, or anything else in regards to his daily life that may be helpful to know about his situation.  Your veterinarian will collect all this information in order to help her rule out other possible diagnosis that can produce hair loss with similar symptoms.  

Your veterinarian will then continue by performing a full physical exam on your dog.  While it may be obvious where the fur loss is occurring, she will want to do a full evaluation of his entire body system.  She will want to check for other areas of fur loss or skin abnormalities that may be the primary cause of the fur loss.  During her examination, she will watch for signs of itching, check for evidence of parasites, look for skin abnormalities, and give him an overall evaluation.  

Your veterinarian will come to her diagnosis by ruling out other possible causes of his symptoms.  There are similar conditions that can result in fur loss for your dog.  Diagnostic tests she may perform include skin scraping, skin cytology, blood work, allergy testing, and a check for parasites.  The skin scraping will be done to rule out skin mites.  A skin cytology can rule out a bacterial or yeast overgrowth of the skin that can lead to loss of fur.  

If your veterinarian suspects environmental allergies, there is a blood serum test that can test what your dog is allergic to.  If she suspects a food allergy, she will recommend you do a food trial to either rule this out or confirm it.

If she suspects an endocrine disorder, laboratory work will need to be performed.  General blood work will consist of a complete blood count (CBC) and chemistry panel.  This will give an overall look at your dog’s internal organ function and blood count.  A urinalysis will also be recommended to check the bladder and kidney function.  Depending on the lab work results and your dog’s symptoms, your veterinarian will then recommend more detailed diagnostic blood work.  There is a test specifically for the thyroid function evaluation she will recommend to rule out a thyroid disorder.  If she suspects Cushing’s or Addison’s she will have those tests run as well.

The combination of blood work results, urinalysis results, and your dog’s physical symptoms will diagnose your dog’s problem.  Once he is diagnosed with an endocrine disorder, treatment can start accordingly.

If your dog has hyperthyroidism or hypothyroidism, he will be started on thyroid medications to bring the thyroid levels back within the normal ranges.  If your dog has Addison’s disease or Cushing’s disease, there are medications and therapies your dog will need to be started on.  He may even need these medications for the rest of his life.  If you do not correct his endocrine levels, he will continue to have the hair loss and it will likely progress.  He will be prone to developing other illnesses and will have an overall lower quality of health.  

If your dog is simultaneously battling other issues, your veterinarian will be sure to address them as well.  For example, if there is a secondary infection of the skin that can be related to his fur loss, your dog will be prescribed an antibiotic and possibly steroids to cure the infection.  If he is losing or gaining weight excessively due to his condition, this will also be addressed by your veterinarian.

If you are able to have your dog’s condition properly diagnosed and treated, he should recover without a problem.  Once treatment begins to work, his fur will start to grow back. If you do not treat his condition, his fur loss will remain present and is very unlikely to grow back without medical intervention.