My Dog Has Crusty Scabs On His Back – What To Do?

As fur parents, any sign of discomfort or sickness is a cause for worry. And one of the most common reasons for panic among dog owners is the presence of crusty scabs on our dog’s skin.

These unsightly patches are often accompanied by behavioral changes. Your dog may be itching, licking, or nibbling the area. Increased verbalization in the form of whining, attempts to protect the area from being touched, and signs of aggression may also be observed.

This is definitely a cause for concern, but it is important to stay calm. Skin diseases may be distressing to dogs, but the majority of them are not instantly life-threatening and finding out what is causing the scabs is the key to getting your dog better.

And while the veterinarian has the diagnostic tools to find out what’s wrong and how to treat it, she will need your expertise as your dog’s best friend to narrow down the long list of reasons why your dog is developing these scabs.

Common Causes For Crusty Skin In Dogs

The skin is every animal’s first line of defense against the environment. As such, we can expect that it meets many different kinds of pathogens and irritants that could potentially cause this reaction. But the skin is also the largest organ in the body, and it interacts with our internal organs in intricate ways that we do not even fully understand. This means that what happens inside an animal’s body could manifest on the outside.

In a nutshell: there are many reasons why your dog could be developing scabby patches of skin. Being familiar with the most common among them will help you answer your veterinarian’s questions when they ask about your dog’s history, an indispensable part of their reaching the right diagnosis.

Ectoparasite Infection

Fleas, ticks, and mites are just some of the ectoparasites that fur parents are familiar with. Some can be seen with the naked eye, while others will require the use of a microscope to be visualized. Scaly and crusty skin is the result of irritation when ectoparasites bite or burrow into the skin.

This is a reasonable cause for concern because some parasites can transfer zoonotic disease to humans. A tick enjoying your dog’s skin may crawl to your bed and transfer an infection to you and your family. This is why regular ectoparasite prevention is a hallmark of responsible pet ownership.

The chance that ectoparasites could be behind your dog’s scabby dilemma becomes higher if you answer yes to any of these questions:

  • Do you see fleas or ticks on your dog’s skin or on their beddings?
  • Has your dog been outdoors, particularly grassy and wooded areas?
  • Has your dog recently had contact with animals who have an ectoparasite infestation?
  • Have you missed your most recent ectoparasite prevention schedule?

If these are relevant, be sure to mention it to your vet!

Allergic Reaction

Yep, dogs can have allergies too! Just like humans, they can be allergic to food, medications, chemicals, and environmental factors like insect bites or pollen. Indeed, there are many ways an allergy can manifest, but among the most common symptoms is itchy, red, and dry skin. These reactions may occur seconds after exposure (such as skin contact with irritating chemicals), or hours after exposure (such as ingesting an allergen in food).

It can be quite difficult to determine if an allergy is indeed the cause for your dog’s crusty skin, but it’s even harder to pinpoint exactly which allergen is involved. Your dog may have to undergo different kinds of diagnostic tests to rule this out.

When we think of allergies, we think that it happens after exposure to something new. But in fact, allergies can be developed, this means that your dog’s immune system can react disproportionately to something that he has been eating or exposed to for months.

Finding out your dog’s allergy requires (1) knowing exactly what your dog eats or gets in contact with, and (2) close observation over a long period of time. Here are some questions you can ask yourself to help your vet determine if an allergic reaction is the source of the problem:

  • Did anything unusual happen in the last 24 hours?
  • Has there been a recent change in your dog’s routine?
  • Has there been a recent change in the products you use on him or his things?
  • If this isn’t the first time your dog has developed crusty skin, do you notice any patterns among the previous incidents?

Bacterial Or Fungal Infection

The combined efforts of the skin, the immune system, and the normal skin microbiota usually hold a pretty good defense against pathogens. But when one or more of these are compromised, pathogenic microorganisms stand a chance.

Bacteria and fungus can penetrate the defenses when there is a break in the skin such as wounds, scratches, or even insect bites. An immune system that is already fighting a different pathogen may not be able to protect the body from the influx of pathogens. When the colonies of good bacteria and fungus on the skin die, the layer of protection they provide disappears with them, giving bad bacteria and fungus a chance to grow in their place.

It is important to note that infections may be secondary to existing health problems that may or may not be skin-related. In this case, treatment will involve eradicating the pathogens and working on the underlying problem.

Keeping your dog clean using gentle, vet-approved shampoo can help prevent infection. Remember that microorganisms love moisture and heat, so remember to dry out areas that retain these, such as armpits, in between paws, and the genital area.

To help you vet to assess the likelihood of bacterial or fungal infection in your pet, reflect on these questions:

  • Has your pet visited woody or grassy areas lately?
  • Does your dog have a tendency to roll in dirty or wet areas?
  • Before the crusty area appeared, was your dog already scratching or licking the place?

Nutritional Deficiency

Eating healthy isn’t just for humans, but for dogs too! Making sure your furry best friend’s nutrient requirements are met is important for so many reasons, not least of which is the quality of his skin and coat. It’s more than just aesthetics too! Healthy, well-hydrated skin and a shiny coat of fur give better protection than dry, inflamed skin and a dull coat.

Among the most important ingredients for healthy skin and lustrous fur are the omega fatty acids. There are two main kinds, and together, they help your dog mount a balanced immune response. Omega-6 fatty acids help the immune system react quickly to pathogens, while omega-3 fatty acids stop the immune system from overreacting to pathogens.

A deficiency in these essential fatty acids is usually caused by poor diet. While most dog food companies are aware of the effect of omega fatty acids and make sure to incorporate it into their feed, there are some that may not give it in the amounts required. Picking high-quality dog food can save you and your dog from a lot of health issues.

Homemade dog food is fast gaining popularity, but many focus too much on meeting protein requirements. However, your furry buddy needs his fill of fats, minerals, and vitamins too. Before you start, read up on how you can prepare balanced home-cooked dog food and confirm with a vet if your meal plan is appropriate for your pet.

Want to know if your dog’s diet is the cause of poor skin quality? If you answer “no” to the questions below, make sure to mention them to your vet.

  • Can you recognize the ingredients in your dog’s food as something you can buy at the supermarket?
  • Is your homemade dog food made of more than three ingredients?
  • Have you been feeding this food to your dog for less than a week?

Hormonal Dysfunction

If puberty had you sprouting pimples and hair in weird places, then you would know that hormones play a huge role in one’s appearance. The same goes for dogs.

The endocrine system is comprised of different glands all over the body that interact with each other in complex ways. It helps to think of a gland as a boss who gives instructions to a company. If the instructions get muddled up, it won’t just affect sales, it will affect finance, logistics, and HR too. In the same way, hormone imbalance in one gland could manifest in many different parts of the body.

The most common endocrine glands involved in skin and coat changes are the thyroid and adrenal glands. They might produce too much or too little of a particular hormone that affects the immune system, hair growth, skin elasticity, among others.

Hormonal dysfunction could be considered a possible suspect if:

  • You notice behavioral changes like lethargy, appetite loss, or increased urination alongside coat and fur problems.
  • Your dog has been taking medication for a long period of time.
  • Your dog’s breed has a genetic predisposition to endocrine disorders such as hypothyroidism and hyperadrenocorticism.

Autoimmune Disorders

The immune system is a powerful way for the body to protect itself, but it can also be its own worst enemy. This is the case for autoimmune disorders, wherein the immune system starts to attack the cells of its own body. Why this happens is not yet completely understood but breed disposition and immune triggers appear to be significant factors.

Crusts appearing on the skin are most associated with pemphigus and lupus. Pemphigus is a complex of diseases that all start with white blood cells attacking desmosomes, the cellular structure that acts like glue holding adjacent cells together. Destroyed desmosomes in the skin will manifest as inflamed skin that easily breaks.

Lupus is a large family of diseases wherein the immune cells attack the body’s tissues. When the tissue in question is the skin, the complex of diseases under cutaneous lupus erythematosus is the most likely culprit.

While autoimmune disorders are quite rare compared to the other causes of poor skin condition, it is worth discussing as your veterinarian may want to rule this out. If you answer yes to the questions below, make sure to let your vet know.

  • Do the crusty patches occur in the same area on both sides of the body?
  • Do the symptoms come and go every few months?
  • Is your dog’s breed genetically predisposed to these autoimmune disorders?
  • Do you notice color changes in your dog’s skin, particularly in the paw pads and nose?
  • Are there behavioral changes that occur alongside skin symptoms?
  • Is the condition exacerbated after spending time under the sun?


Getting to the bottom of your dog’s skin disease is a complex process that may involve several of the conditions mentioned above. Depressed immune systems could set the stage for the bacterial infection, poor nutrition could aggravate allergies, hormonal imbalances could trigger fungal growth, and so on.

Your knowledge of your dog’s behavior, symptoms, and medical history can help your vet pinpoint which diagnostic tests to do to figure out what is wrong. By narrowing down the possibilities, you save on money for tests and help your dog get the most suitable treatment for his condition.

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Regina Ranada

Regina graduated with a degree in Psychology and worked in Human Resources for four years before she decided to pursue her dream of becoming a veterinarian. She is interested in companion animals and wildlife medicine. She sidelines as the social media manager of her pitbull, Pablo.

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