Table of Contents
What is Canine Seborrhea?
Seborrhea is a term used to describe a group of skin diseases where there is excessive flaky skin. Seborrhea is not a specific diagnosis but rather, a description that embodies multiple diseases that result in seborrheic symptoms.
The terms associated with canine seborrhea can be confusing and are often incorrectly used interchangeably. The term “seborrhea” itself is actually more of a description rather than a diagnosis of a specific disease process. Canine seborrhea typically refers to dogs with symptoms associated with changes in the skin renewal process. But there are multiple possible diseases that can cause seborrheic symptoms in dogs.
Canine seborrhea can appear in different ways in different dogs depending on the underlying cause. For example, dogs with seborrhea can either have very oily or very dry skin. However, in general, all seborrheic dogs tend to have overly flaky skin.
Symptoms of Seborrhea in Dogs
The physical manifestation of canine seborrhea can be divided into two main groups: seborrhea sicca and seborrhea oleosa.
Seborrhea sicca is the more common presentation in dogs and is characterized by dry, white scales that are shed fairly easily. In other words, these dogs have a lot of what we colloquially refer to as dandruff. “Sicca” means dry. Dogs with this type of seborrhea tend to have a dry and dull coat because they produce less of the oily substance known as sebum.
In contrast, seborrhea oleosa is associated with very different symptoms. These dogs typically have greasy skin and an oily hair coat. The scales or dandruff observed with seborrhea oleosa are usually yellow or brown and are often stuck to the fur in chunks. This is because these dogs usually produce too much sebum. Because of this additional sebum, dogs with seborrhea oleosa often have an unpleasant odor, similar to that of oil or grease.
Dogs with seborrheic dermatitis also tend to have inflammation, which may result in red skin. Chronic inflammation of the skin can lead to hyperpigmentation, or darkening of the skin.
We often forget about the skin inside our dogs’ ears. But the rapid skin turnover in seborrheic dogs also occurs in their ears. This is why dogs with seborrhea may also have increased ear wax and debris. Because of this, some seborrheic dogs are more likely to develop ear infections.
In dogs with seborrhea, the normal barrier function of the skin is compromised. This puts these dogs at higher risk of developing secondary infections. Dogs with bacterial or fungal infections like yeast infections are often itchy and may have crusts, pimples, and hair loss.
What Causes Seborrhea in Dogs?
The flaky skin seen with dog seborrhea is due to changes in the skin renewal process. Canine seborrhea encompasses skin disorders with abnormal keratinization of the skin, hair follicles, and nails of dogs. Additionally, seborrhea may be caused by inappropriate lipid production by the skin.
The skin is constantly renewing itself. Keratinization is the turnover and renewal processes of skin cells, called keratinocytes. The skin is made up of multiple layers. During the keratinization process, old skin cells are shed from the top layer of skin, and new skin cells from the deeper layer of skin mature to take their place.
In dogs with normal, healthy skin, this turnover process takes about 20 to 21 days. But in dogs with seborrhea, this turnover process is much shorter. This translates to faster production of flaky, dead skin.
The main causes of seborrhea in dogs are primary keratinization disorders and secondary seborrheic disorders. If the scaling, or dandruff, seen with seborrhea is due to a problem with the skin renewal process itself, this is referred to as a primary keratinization disorder. Alternatively, if the flaky skin is a result of another disease process, it is considered secondary seborrhea.
Let’s first discuss the causes of secondary seborrhea since these are by far more common in dogs compared to primary keratinization disorders. Many disease processes can cause seborrheic symptoms. For example, allergies, immune-mediated diseases, and endocrine disorders are just a few categories of diseases that can result in the abnormal skin symptoms observed in seborrheic dogs. To make things more complicated, dogs with secondary seborrhea may have multiple diseases contributing to their symptoms.
Categories and examples of causes of secondary canine seborrhea:
Categories and examples of causes | |
|---|---|
Categories of causes | Examples of specific conditions/diseases |
Infectious disease | Secondary skin infection (e.g. bacterial, yeast)
Ringworm |
Allergy | Flea allergy
Food allergy Environmental skin allergy |
Endocrine disorder | Hypothyroidism (decreased thyroid hormone)
Hyperadrenocorticism (increased stress hormone) |
Parasites | Scabies
Demodex |
Nutritional problem | Zinc deficiency |
Immune-mediated disease | Pemphigus foliaceus
Systemic lupus erythematosus Sebaceous adenitis |
Cancer | Cutaneous lymphoma |
Examples of specific conditions/diseases
Primary keratinization disorders, which are also referred to as primary canine seborrhea, are rare. Primary canine seborrhea is essentially a diagnosis of exclusion, meaning we only diagnose primary keratinization disorders after ruling out common causes of secondary seborrhea. Unfortunately, primary keratinization disorders are often hereditary. Thus, to avoid passing this disease onto more dogs, dogs with primary canine seborrhea should not be bred.
Examples of primary keratinization disorders in dogs:
- Vitamin A-responsive dermatosis
- Ichthyosis
- Schnauzer comedo syndrome
- Ear margin dermatosis
How Seborrhea in Dogs Is Diagnosed
As we have discussed, seborrhea is a description rather than a diagnosis of a specific disease. When we say that a dog has seborrhea, we usually mean he has excessively flaky skin. After establishing that a dog has seborrheic symptoms, your veterinarian will need to diagnose the underlying cause.
The first step in diagnosing the cause of a dog’s seborrhea is to consider its signalment, meaning its breed, sex, and age. As a veterinarian, a dog’s signalment helps guide my initial diagnostic process because different diseases are more common in certain breeds and age groups. Additionally, some conditions may be more common in males or females.
For example, dogs with primary keratinization disorders tend to start displaying symptoms at a younger age since many of these conditions are inherited. Additionally, certain breeds such as American cocker spaniels and West Highland white terriers may be more predisposed to primary seborrhea.
As a clinician, an extremely valuable part of diagnosis is taking a thorough history. Gathering a history costs no money but still provides crucial clues about what may be affecting a patient.
Your vet will ask you about your dog’s symptoms. An important symptom your veterinarian will ask about is itching. This is because the presence of itching is often associated with external parasites like fleas. Other symptoms like changes in water intake, appetite, and urination are also important to note since these may increase the suspicion of endocrine disease.
Your veterinarian will also likely ask you about the onset and progression of your dog’s symptoms as well as whether they are seasonal. Information about your dog’s diet and environment also provides important context, especially in suspected cases of allergy. Another important piece to consider is whether a dog has already been previously treated for his symptoms and if so, whether or not he responded positively to that therapy.
After collecting a history, your vet will perform a physical exam of your dog. In addition to evaluating all of your dog’s organ systems, your veterinarian will carefully assess your dog’s skin and ears. She will note any lesions as well as their location since the distribution of skin lesions gives us hints about possible underlying conditions. Examination of the skin gives your vet the opportunity to look for things like fleas and broken hairs, which may indicate itching.
Using the information from your dog’s history and physical exam findings, your veterinarian will prioritize which diagnostic tests are indicated. She will recommend certain tests based on the most likely possible disease processes she suspects. In cases of dog seborrhea, your vet will likely recommend skin cytology to check for secondary infections. Other tests your veterinarian may recommend include a skin scraping to look for mites, fungal and bacterial skin cultures, bloodwork and urine tests to assess for systemic disease, and a skin biopsy if there is a concern for immune-mediated disease or cancer.
On rare occasions, all of these tests may be normal. In these cases, when all or most of the possible causes of secondary seborrhea are excluded, your veterinarian may diagnose your dog with primary seborrhea. A diagnosis of primary seborrhea essentially means that no other disease process could be identified which could be causing your dog’s skin abnormalities. And as such, it is suspected that your dog’s skin changes are due to the skin renewal process itself.
Treatment for Seborrhea in Dogs
Any secondary infections that are identified should be treated with topical and/or oral therapies as appropriate. It is important to treat any secondary infections since these infections can cause significant itching and discomfort.
If an underlying cause of seborrhea is identified, it should be treated accordingly. For example, a dog diagnosed with hypothyroidism may require thyroid hormone supplementation while a dog with vitamin A-responsive dermatosis should be treated with vitamin A.
Regardless of the underlying cause, all dogs with seborrhea should be bathed regularly with medicated, anti-seborrheic shampoo. Anti-seborrheic shampoos serve a few different functions in dog seborrhea treatment. They are keratolytic, meaning they encourage the top layer of dead skin to shed. Anti-seborrheic shampoos are also keratoplastic, which means they help correct the rate of skin turnover so that flaky, dead skin is not produced as quickly.
These medicated shampoos sometimes have additional benefits depending on what ingredients they contain. For example, they may have ingredients aimed at reducing bacteria or yeast. These shampoos may also have hydrating ingredients, which may be useful for dogs with seborrhea sicca. Alternatively, there are anti-seborrheic shampoos designed for seborrhea oleosa, which instead contain ingredients that degrease the skin and coat.
When I prescribe medicated shampoos to pet owners, the most important aspect I emphasize is contact time. Many of the active ingredients in these medicated shampoos are only effective if they are in contact with the skin for a certain amount of time. I recommend waiting at least 10 minutes before rinsing off the shampoo. I understand that 10 minutes may seem like a long time. Thus, I recommend using treats or a lick mat with peanut butter to distract your dog until the 10 minutes are up.
So how frequently do you need to bathe a seborrheic dog? It really depends on the severity of that individual dog’s seborrhea and whether there are other issues such as secondary skin infections. Therefore, please defer to your veterinarian regarding how frequently to bathe your dog.
In general, you will need to bathe a dog with seborrhea more frequently than a dog with normal skin. But once the symptoms are well-managed, the frequency of baths can be reduced. However, I always prepare owners that if their dogs have any type of skin issue, including seborrhea, they will likely need to continue medicated baths fairly regularly as a long-term management strategy. This form of regular topical therapy acts as maintenance therapy to prevent their dogs’ seborrhea from flaring up again and leading to secondary skin infections.
In addition to topical therapy in the form of regular medicated baths, there are also a few systemic treatment options for canine seborrhea. For dogs with seborrhea sicca, essential fatty acid supplements may improve the dryness associated with their skin and hair coat. Although these supplements are available over the counter, you should always consult your veterinarian before administering any new supplements to your dog. I also always caution owners to introduce fatty acid supplements gradually because they can cause diarrhea.
There are a few other systemic treatment options available but they are only appropriate in certain situations. Therefore, if you are curious about other available treatment options, such as retinoids, I recommend asking your veterinarian if these are safe or relevant options for your canine companion.
Recovery of Skin Disease (Canine Seborrhea) in Dogs
When the underlying cause of a dog’s seborrhea can be identified, the prognosis is usually quite good. Many causes of secondary canine seborrhea can be treated and even cured completely. As long as the underlying disease can be well-managed, we can often significantly decrease or even eliminate a dog’s seborrheic symptoms.
Unfortunately, primary keratinization disorders are usually much more difficult to control. While many causes of secondary seborrhea can be treated, primary keratinization disorders are not typically cured. Instead, primary keratinization disorders require long-term management which can be frustrating and expensive. Thankfully, these forms of primary seborrhea are not very common.
If the underlying cause of a dog’s secondary seborrhea can be identified and treated successfully, then his seborrheic symptoms often improve significantly. But in cases of primary keratinization disorders, it can be extremely difficult to control seborrheic symptoms and lifelong therapy is often necessary. Fortunately, topical therapy with regular medicated baths is an effective strategy to manage the symptoms in dogs with seborrhea.
Environmental factors can trigger seborrheic dermatitis in dogs. For example, dry climates with low humidity may trigger the scaling seen with seborrhea, especially in dogs with the dry form of seborrhea (aka seborrhea sicca). Additionally, frequent bathing and grooming are also potential triggers.
If a dog has the oily form of seborrhea known as seborrhea oleosa, he may smell strongly of oil or grease. Dogs with seborrhea are more prone to secondary skin infections, which if present, typically exacerbate their canine seborrhea smell. For instance, dogs with yeast skin infections may have a musty odor or smell like moldy bread.
Dr. Amanda Takiguchi received her Doctor of Veterinary Medicine degree at Colorado State University. After that, she completed additional training at Texas A&M through a small animal rotating internship. Prior to veterinary school, Dr. Takiguchi studied dance and business management at Columbia University in New York City. She primarily works with dogs and cats but also loves exotic species like rabbits. Her favorite animal that has worked with is the native Hawaiian owl. When she is not promoting animal welfare, Dr. Takiguchi still loves to dance, with training in multiple styles including hip hop, ballet, and tap.
