Scaly skin in pets may be nothing much to worry about. But if it’s excessive, it can signal a more serious underlying issue, and should be checked out.
Scaly skin, often referred to by pet owners as “dandruff”, is a common condition in dogs and cats. While it can often be “no big deal,” excessive scaliness is sometimes a symptom of something more serious. This article will explore the various causes of scaly skin in dogs and cats, and how they can be treated.
Understanding the skin
The epidermis of the skin has five layers: the basal layer (which provides new skin cells that migrate to the surface of the epidermis), the spinous layer, the granular layer, the clear layer, and the horny layer (the stratum corneum, the uppermost layer of the epidermis that protects the pet’s body from external assaults). The cells of the stratum corneum are constantly being shed, since they are technically dead skin cells. These dead cells are replaced by cells from the basal layer. The process of shedding dead cells and replacing them with new cells takes approximately 22 days in pets. When this process is interrupted, scaliness results and is seen as the white flakes we call scale (or “dandruff”) on the skin and coat.
By itself, the presence of scale is not specific to a disease but rather indicates some malfunction of the normal growth process of the skin’s epidermal layer. Excess scale on the skin indicates a problem (that may or may not be serious) which should be examined.
What causes scaly skin?
There are numerous causes of scaliness, so testing must be done to determine the specific cause and hence the proper treatment. In my practice, the following causes are the most common:
- Some dogs and cats show excessive scaliness without a definitive cause, and sometimes it’s worse during certain seasons of the year (typically the winter when there is less humidity). The only way I can arrive at this diagnosis, however, is to rule out other causes of scaliness via diagnostic testing (more on this later).
- Here in Texas, I commonly diagnose allergic skin disease in patients. These pets may exhibit excess scaliness or greasiness.
- Primary or secondary infections, typically from bacteria (sometimes MRSA) or yeasts (usually Malassezia), often result in scaly skin. Bacteria usually cause scaliness, whereas yeasts usually result in greasy skin.
- Parasites, especially fleas, can cause either scaly or greasy skin. In certain areas of the country, lice can also cause epithelial disorders resulting in scaliness. Infection with a specific mite (Cheyletiella) results in a specific type of scaliness called “walking dandruff”. In this condition, the scale actually “moves” or “walks” when closely observed. The mites are easily seen when the “dandruff” is examined microscopically.
- Ringworm is not as common in older pets as most people think (it’s much more common in puppies and kittens), but when it occurs, this fungal infection usually causes scaling.
Even though these external causes of scaly skin are most common, there are also internal causes. Thyroid and adrenal disease can affect the skin and hair, but so can any other internal disease including cancers, diabetes, and conditions of the liver and kidneys.
Diagnostic testing is important
When determining the cause of scaly skin in a dog or cat, I usually start with easy tests I can do in the office, such as a skin scraping (looking for mites and lice), and a skin cytology (looking for yeasts and bacteria). I also send off a blood profile to look for problems such as thyroid and adrenal disease, and run a fecal analysis (for GI parasites) and urinalysis (to evaluate kidney and bladder function).
If I don’t get a diagnosis with these tests and suspect further investigation is needed, I schedule the pet for a skin biopsy. This allows me to remove a few small pieces of affected skin for the pathologist to review microscopically, and for the microbiologist to culture and look for bacteria in (especially MRSA, a severe form of Staphylococcal infection I wrote about in a past issue – see AW Dec-Jan 2015/16).
Following this testing, I arrive at a diagnosis. If no diagnosis is reached, then the scaliness is not caused by any of the mentioned diseases, and I treat the pet using holistic therapies to control (and possibly cure) the problem. If a definitive diagnosis is made (hypothyroidism, mange, skin infection, etc.), the appropriate treatment is given along with regular shampooing, fatty acids, and antioxidants.
Because scaliness is a skin disorder, it makes sense to treat it topically by shampooing. Various ingredients in the shampoo can normalize the epithelial rate, remove excess scale, and kill pathogenic organisms that may contribute to scaliness. The ingredients typically seen in conventional pet shampoos for this purpose include selenium, salicylic acid, coal tar (for dogs only, as it’s too toxic for cats), and ketoconazole (a potent antifungal medication). In general, mild cases of scaliness respond to ingredients such as selenium or salicylic acid, while more severe cases may require “harsher” treatment with coal tar shampoos.
As in people with dandruff, frequent bathing is important. I usually recommend daily shampooing for one to two weeks, and then a maintenance protocol of one to three times weekly.
Nutrition and supplements also play an important role in controlling scaly skin.
- A high quality natural food is crucial for minimizing the scaliness that can occur with low end foods filled with additives and poor quality ingredients.
- Fatty acids are helpful when given orally or applied topically in a conditioner or after-bath rinse. For scaliness, orally-administered fatty acids are usually given in at least double the label dose.
- Antioxidants help reverse oxidative damage to the skin, reverse inflammation, and control itching.
Scaly skin on a dog or cat is unsightly and may be uncomfortable for the animal, so get it checked out by a veterinarian. Chances are, it’s nothing much to be concerned about, but if it’s excessive, it could signal a more serious condition, and the sooner it’s caught, the better the outcome for your best friend.