Probiotics: Do they work for dermatology patients?

Karen Helton Rhodes, DVM, DACVD             Veterinary Dermatologist

Canine Skin Solutions, Inc.

The intestinal tract contains trillions of microbes in the gut.  That is approximately 10 times the number of cells in the body! These microorganisms influence the health of the host in a number of different ways: provide nutritional substrates, modulate the immune system, and provide defense against microbes that may cause disease.

The current trend of using probiotics is an attempt to harness the beneficial power of these microbes.

What we know “to date”:

1.  Dogs with inflammatory bowel disease have an altered intestinal microbiota (decreased Faecalibacterium spp. & Fusobacteria).  Most of the GI studies evaluating manipulation of the flora have been done on healthy dogs. Additional controlled studies need to be evaluated using dogs with inflammatory gastrointestinal diseases.


2.  Pet food industries and animal health and wellness groups are actively marketing probiotics. Probiotic formulations must be safe, pure, and stable.  Not all products on the market are considered equivalent. Most of these products are marketed for the GI tract (diarrhea). Unfortunately, there is little data to support their claims.


3. Criteria necessary to ensure safety and efficacy of probiotics: they must resist gastric acid and bile degradation, have the ability to colonize the GI tract, show efficacy against microorganisms that can cause disease, and have the ability to modulate the immune system.


4.  Current theories as to how probiotics can exert a beneficial response on the gut (diarrhea): competition with bacteria that cause disease, competition for receptor sites, modification of the metabolic activity of the bacteria in the gut, direct influence by the action of certain metabolic products against bacteria that cause disease


5. Most of the studies in dogs to evaluate probiotics are not randomized controlled trials and, unfortunately, the strains of bacteria varied in each study.  This makes it difficult to interpret the results and value the data. Those studies showed an “improvement in the diarrhea” but failed to show a change in the immune (inflammatory cytokine pattern) response.


6.  Skin Data:  A recent study (2015) using Lactobacillus sakei (Probio-65) administered for 2 months to research dogs with Atopic Dermatitis (allergy) showed a decrease in pruritus (itching) in the test group.


7.  Veterinary Dermatologists have used a variety of strains of probiotics in clinical practice with varied results.  Unfortunately, it is difficult to assess the response since there is no standardization of therapy or product used. At this time, we cannot say  “probiotics are beneficial” in our dermatology patients BUT, in most cases, they do not appear to be harmful! It might be worth a try.


Don’t be confused by the term “Prebiotics”.  These are nondigestible food ingredients that may promote the activity and growth of healthy bacteria in the gut.  Prebiotics are typically ingredients such as fructans, mannans, lactosucrose, and lactulose.


The exact role of probiotics and prebiotics in dogs is largely unknown. They are primarily being evaluated for their effects on the gut in controlling chronic diarrhea.  Studies involving skin diseases are limited. It is not known if the probiotic must include live microorganisms since it is likely that the effects are mediated by the organism’s DNA.  More studies are needed!


Probiotics have become a trend in veterinary medicine.  There is little critical evidence to support their use. That said, research may yet prove them to be a useful tool when used appropriately and under the advice of a veterinarian.