Common Dog Misdiagnoses: Skin Issues

Veterinary (and human) medicine is at least as much of an art as it is a science.  What does this mean for dog owners?

Common Dog Misdiagnoses: Skin Issues Misdiagnoses

You should consider any diagnosis that your dog receives to be a “work in progress.”

No vet would intentionally misdiagnose a dog. However, certain diseases are notoriously difficult to pin down. If your dog is

  • not responding to treatment as expected
  • the disease is progressing in an unusual manner,
  • or your gut is telling you that something just isn’t right, talk to your vet. 

He or she should be open to reevaluating the situation. If not, get a second opinion.

Skin Problems

Dermatological conditions can be frustrating to diagnose.  The skin responds to virtually any insult – bacterial infection, parasites, immune disorders, etc. – with the same symptoms. Diagnostic tests are usually necessary to reveal the cause.

Remember though that no test is perfect, false negatives and false positives do occur. Therefore, if lab results do not mesh with a dog’s clinical picture they need to be questioned.

To confuse the situation, even more, some skin problems, like bacterial or yeast infections, almost always develop because there is an underlying condition that has disrupted the skin’s normal defensive mechanisms.

If your dog has been diagnosed with a skin infection that is not going away with treatment or comes back when treatment is stopped, you and your vet will need to start looking for the reason why.

Allergies are a common underlying cause of recurrent skin problems in dogs.

But, the only way to know for sure that a dog has allergies and what his triggers are is through allergy testing.  Intradermal allergy tests are best.  Blood testing is another option, but the results are not as accurate.

Many vets (myself included) are willing to diagnose allergies without allergy testing after ruling out other common causes of itchy skin. And this is appropriate as long as owners are aware of the plusses and minuses of this approach.  If, however, a dog’s condition doesn’t respond to treatment as expected, the initial diagnosis should be reevaluated.

Hormonal Diseases

Getting to the bottom of hormonal diseases can also be difficult.  Hypothyroidism is an excellent example.


A low total thyroid level on blood work alone is not sufficient to reach a diagnosis of hypothyroidism.  

Dogs must also show some of the typical signs of the disease such as

  • weight gain
  • low energy levels
  • cold intolerance
  • hair loss, or skin problems

These issues should improve once thyroid supplementation has been started.

A condition called sick euthyroid syndrome can also cause thyroid hormone levels to fall, but this is not true hypothyroidism and treatment with thyroid supplements is not beneficial.

Cushing’s disease is another tough one.

A vet might suspect its presence after if they find

  • elevated alkaline phosphatase (ALP) levels on routine blood work or
  • high cortisol levels on a urine test

Still, either a low dose dexamethasone suppression test or an ACTH stimulation test is necessary to confirm the diagnosis.

However, such advanced testing may not be necessary early in the course of the disease because in most cases, Cushing’s disease shouldn’t be treated unless a dog has symptoms that are starting to interfere with its quality of life (e.g., increased appetite, thirst, and urination, skin and coat problems, or a pot-bellied appearance).  This is another situation where a big-picture approach is necessary.

Addison’s disease is probably even more frequently misdiagnosed than is Cushing’s.

The typical symptoms – vomiting, diarrhea, weakness, collapse – can occur as a result of a whole laundry list of health problems.  In many cases, a fairly distinctive change in blood electrolyte levels occurs with Addison’s disease. But electrolytes are not always included in panels of routine blood work.  Also, not every victim of Addison’s has these electrolyte changes.

An ACTH stimulation test is the only conclusive way to determine whether or not Addison’s is responsible for a dog’s clinical signs.

Related articles:
Common Dog Limp Misdiagnoses

Further reading:
Skin Problems in Dogs in Pictures

  1. We used to hear a lot about skin issues with dogs when I was working in retail. Allergies are a lot more common in pets than people seem to think. Definitely more common in dogs I think. I saw a lot of people rushing to change their dogs diet without even considering what environmental exposure factors might be involved from grasses to lawn care products to the laundry detergent used to wash their beds.

  2. My dog Nelly seems to have seasonal allergies, but my vet has never suggested running allergy tests. I’ll have to ask her about testing Nelly. It would be great if I knew exactly what she is allergic to (if anything) and perhaps I could take some different steps to prevent a reaction. Or alternatively, find out what is really going on.

  3. Marjorie Dawson

    Hmm and I thought vets mostly got it right! They work with what they can see and testing I guess, and it can’t help that many symptoms look similar.

    Thought provoking and interesting to read about this and I know dog owners will find this of great help.

  4. Layla suffers from terrible allergies and have found what is working for her more and more is not medications but wiping her down when we come in, salmon oil in her food plus a couple of drops of Rooibos tea, and since doing that her itching and scratching is less and less plus phew no hot spots

  5. This post is perfect time for me. Thank you for educating everyone on misdiagnosing skin issues. Two of my dogs are currently suffering from “allergies” and I’m seriously thinking about getting a second opinion. We haven’t done the allergy tests yet but I’m really wondering if this is a secondary thing.

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