French Bulldog Skin Problems: Infections & the Nasomaxillary Skin Fold Microbiome

Bulldogs, boxers, and pugs, oh my! These are just a few of the many breeds of brachycephalic dogs, defined as dogs with flattened faces [1]. As cute as their smooshed faces may be, these breeds are particularly prone to skin infections (like intertrigo) due to moisture-retaining skin folds that provide the ideal breeding ground for opportunistic bacteria and fungi [1].

A recent study using Next-Gen DNA Sequencing (NGS) was conducted to assess the skin fold microbiome in healthy French bulldogs and determine how the microbiome is influenced by topical medications. Considering the need for alternative approaches to normalizing the epidermal barrier and lessening the severity of intertrigo presentation due to increasingly resistant strains of bacteria, this research holds significant implications for how intertrigo can be diagnosed and treated [2]. Read more to learn about intertrigo and advancements in clinical diagnostics for your wrinkly pup!

So What is Intertrigo?

Intertrigo, also known as skin fold dermatitis, is a common skin condition in brachycephalic dogs caused by a unique combination of epidermal trauma (associated with skin friction) and environmental moisture that allows microbial organisms to thrive [3]. The clinical manifestation of this condition results from an imbalance in the dog’s microbiome, which includes fungi, bacteria, viruses, protozoa, and phages [2]. Notably, a healthy nasomaxillary microbiome can actually prevent the colonization of pathogenic organisms [2]. Intertrigo causes recurrent/continuous episodes of scratching, rubbing, chewing, and licking, ultimately resulting in the inflammation and damage of your dog’s skin [4]. While studies of the nasomaxillary microbiome are limited, current research suggests Staphylococcus, Streptococcus, Pseudomonas, and Malassezia species are implicated in intertrigo manifestation.

Intertrigo can range from being mild to extremely painful, and so it is important to be on the lookout for symptoms that include but are not limited to:

  • Excessive itching
  • Redness and inflammation
  • Irritation in armpits, groin, eyes, ears, snout, and between toes
  • Skin lesions, blisters, and/or hives
  • Skin and ear infection
  • Flaking or crusting skin

If you think your dog may be suffering from intertrigo, please consult with a veterinarian as soon as possible. In some cases, surgical intervention may be necessary to remove excess skin folds that create the environment for intertrigo-associated microbiota to proliferate [5]. A topical antibiotic ointment such as mupirocin may be recommended in cases of severe bacterial overgrowth, but increasing mupirocin resistance in canine staphylococci is raising alarm for treatment interventions [2].


The image depicts inflammation and redness associated with intertrigo.

Characterizing the Nasomaxillary Fold Microbiome

Conventional culture-based methods have been found to have significant limitations in determining the nasomaxillary microbiome, largely due to the variability in culturing different bacteria from a plethora of diverse genera [6]. Moreover, characterizing the fungal organisms in your dog’s skin folds are difficult through culture based methods, as this process not only takes weeks but also can result in no growth results [6]. Recent advances in next-generation sequencing (NGS) technologies allow metagenomics analysis, and have provided exciting and practical opportunities for canine intertrigo interventions.

“Multi-drug antibiotic resistance has further complicated [treatment] and made both topical therapy selection and diagnostic testing of the utmost importance.”

Particularly, a recent study was conducted using MiDOG NGS technology to assess the skin fold microbiome in healthy French bulldogs. This study found that the primary skin bacterial phyla populating the nasomaxillary skin fold were Firmicutes, and Proteobacteria, while the primary skin fungal phyla were Ascomycota and Basidiomycota [2]. Also, the researchers noted a significant correlation between the abundance of potentially opportunistic pathogens and microbial diversity. Healthy French bulldogs contained high ratios of clinically relevant pathogens (36.4%) in their nasomaxillary skin fold microbiome [2].

Additionally, the study looked at how topical treatment impacts the diversity of bacterial and fungal compositions over time, which is clinically useful because it can provide an alternative to antibiotic treatment. The dermal treatments analyzed in this study looked at a protease product (Kalzyme) that inhibits biofilm formation but has no biocidal activity and a 2% chlorhexidine diacetate (Nolvasan; CHX) solution, which has broad spectrum biocidal activity against bacteria and fungi [2]. Interestingly, diversity increased by 38% for the protease group, as opposed to 11% for the CHX group.

Since the topical therapy with protease increases microbial diversity in the skin folds and reduces the relative abundance of pathogens, this therapy could hold clinical value in the treatment of intertrigo. As one of the researchers in this study, veterinary Dr. Alissa Rexo notes how “superficial bacterial pyoderma is one of the most common dermatologic diseases in dogs. Multi-drug antibiotic resistance has further complicated this problem and made both topical therapy selection and diagnostic testing of the utmost importance.” Considering intertrigo is one of the most common forms of surface pyoderma, it is important to ask your veterinarian for more information on treatment options.


The image above depicts one of the study participants on Day 0 exhibiting the classic nasomaxillary folds that predispose dogs to intertrigo manifestation.

If you would like to read the full study, please follow this link:

Moreover, MiDOG NGS technology was also used to analyze the bacterial and fungal microbiota in health and diseased skin in one of the largest canine cohort studies to date. This study found that important taxa enriched in disease-state skin included Malassezia pachydermatis, Staphylococcus pseudintermedius, Staphylococcus schleiferi, and anaerobic bacteria such as Finegoldia magna, Peptostreptococcus canis, and Porphyromonas cangingivalis [7]. These findings are particularly notable, as the anaerobic microorganisms identified to be associated with canine skin infections have previously been overlooked by culture-based studies. The potential of NGS-based methods for the accurate quantification and identification of bacterial and fungal populations in diagnosing canine skin infections is remarkable, and highlight the limitations of traditional culture-based testing.

If you would like to read the full study, please follow this link:

The MiDOG All-in-One microbiome test utilizes the NGS technology as described in the study to detect and quantify all microbial DNA through untargeted and comprehensive sequencing and quantitative comparisons to reference databases. Considering shortcomings in culture-based diagnostics, the MiDOG NGS technology provides a useful opportunity to shed light on the microbial makeup of your dog’s nasomaxillary microbiome for clinical application. The MiDOG microbiome test is a microbial identification test grounded on scientific research that provides veterinarians DNA evidence for the guided treatment of canine infections, such as intertrigo.


Find out if your vet uses MiDOG before you book your next appointment!


[1] Fawcett, A., Barrs, V., Awad, M., Child, G., Brunel, L., Mooney, E., Martinez-Taboada, F., McDonald, B. and McGreevy, P., 2018. Consequences and Management of Canine Brachycephaly in Veterinary Practice: Perspectives from Australian Veterinarians and Veterinary Specialists. Animals, 9(1), p.3.

[2] Rexo, A., Hansen, B., Clarsund, M., Krumbeck, J., & Bernstein, J. (2021). Effect of topical medication on the nasomaxillary skin‐fold microbiome in French bulldogs. Veterinary Dermatology.

[3] Gross, T., Ihrke, P., Walder, E., et al., 2005. Skin Diseases of the Dog and Cat. 2nd ed. Oxford: Blackwell Science Ltd; pp261-263.

[4] Anturaniemi, J., Uusitalo, L. and Hielm-Björkman, A., 2017. Environmental and phenotype-related risk factors for owner-reported allergic/atopic skin symptoms and for canine atopic dermatitis verified by veterinarian in a Finnish dog population. PLOS ONE, 12(6), p.e0178771.

[5] Miller, W., Griffen, C., Campbell, K., 2016. Muller and Kirk’s Small Animal Dermatology. 7th ed. St. Loius, MO: Elsevier; pp678-680.

[6] Harvey, N., Shaw, S., Blott, S., Vàzquez-Diosdado, J. and England, G., 2019. Development and validation of a new standardised data collection tool to aid in the diagnosis of canine skin allergies. Scientific Reports, 9(1).

[7] Tang, S., Prem, A., Tjokrosurjo, J., Sary, M., Van Bel, M., Rodrigues-Hoffmann, A., Kavanagh, M., Wu, G., Van Eden, M. and Krumbeck, J., 2020. The canine skin and ear microbiome: A comprehensive survey of pathogens implicated in canine skin and ear infections using a novel next-generation-sequencing-based assay. Veterinary Microbiology, 247, p.108764.

Categories: Dogs, Next-Gen DNA Sequencing Technology, Pet Parents, Skin Health

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Validated by Veterinarians

“Clients expect their veterinarians to stay up to date on all matters that affect the health and well being of their non-human family members. The current technique that we have used to determine the presence and antibiotic sensitivity of organisms causing disease in our pets is over a century old.

With the emergence of dangerous antibacterial resistance, it is critical that veterinarians are able to offer laser focused diagnostics and treatment. MiDog enables us to offer care that exceeds the typical standard of care.”

Bernadine Cruz, DVM, Laguna Hills Animal Hospital Laguna Woods, CA

“I love the absolute abundance and comparing the fungal with bacterial infection. I do not worry as much about getting a false negative urinary infection reading as I do with traditional urine cultures. Several times the same urine would culture negative but MiDOG would detect pathogens.”

Michael Morgan, DVMQuail Animal Hospital, Tustin, CA

“The MiDOG All-in-One Test is amazing, I would use it instead of culture and sensitivity.  Such rapid and detailed results, I will reach for MiDOG before culture next time!

Thank you very much MiDOG, for sharing the opportunity to try your technology.”

Martha Smith-Blackmore, DVM, President of Forensic Veterinary Investigations, LLC – Boston, MA

The MiDOG All-in-One Microbial Test is our new gold standard of pathogen identification. The results are so accurate and valuable – especially with assessing both bacterial and fungal infections with the same sample.

Thank you MiDOG!”

Kathy Wentworth, DVM, Diplomate ABVP Canine and Feline Practice – PetPoint Medical Center, Irvine, CA

“The MiDOG staff was extremely helpful and supportive.”

Cathy Curtis, DVM – London, UK

“I have had great results using the MiDOG® Test. Compared to traditional culture tests, I am better able to target the treatment for dogs because the MiDOG® Test is so sensitive that it identifies all pathogens including bacteria and fungi, as well as antibiotic sensitivity.

The cost and turnaround time are about the same as a culture test, but I get much more data. The test has great performance and I believe the NGS technology will be a game changer for veterinarians treating dogs with lesions or other infections.”

Michael Kavanagh, DVM, Practice owner – Saddleback Animal Hospital, Tustin, CA

“It’s helpful to have an NGS spectrum because it gives you a broader insight of what’s happening and what might be going on.”

Richard Harvey BVSc DVD DipECVD PhD FRSB FRCVS – European Specialist in Veterinary Dermatology – Head of Dermatology, Willows Veterinary Centre & Referral Service – Solihull, England UK

“I have been using MiDog for over 4 years now and exclusively as my test of choice for all cultures for 3 years.  It is so great to submit a culture and feel confident there will be a result when it comes back, especially for urine cultures.  The reports were intimidating at first because they contain so much information.  After the first few, I am now quickly able to glance over it and pick out the highlights.  I can then come back later and pour over all the details.  I have been extremely pleased with my patients’ results using the test as well.  I don’t envision ever going back to traditional culture and susceptibilities again.”

Brian M. Urmson, DVM, Columbiana Veterinary Associates

“As an exotic veterinarian, there are numerous tests we have to consider to check specific bacterial and fungal organisms based on the species. MiDOG eliminates the need for many of these separate samples and provides definitive results quickly to help us treat our patients more efficiently and effectively. The lab is wonderful to work with and has never rejected our samples- they even processed a lizard toe we amputated and determined the cause of skin infection.”

Dr. Melissa Giese, Chicago Exotics Animal Hospital

“MiDOG’s diagnostic approach offers the unique ability to identify pathogens that evade traditional culture and sensitivity testing. I have found that adding a molecular based testing approach in the form of Next Generation Sequencing (NGS) from MiDOG to my routine diagnostic cultures can be extremely helpful in the identification and diagnosis of uncommon pathogens in veterinary medicine.”

Dr. Wayne Rosenkrantz, Animal Dermatology Clinic – Tustin

“She [Dr. Krumbeck] really did a great job of making complicated concepts accessible and demonstrating the value of your services. I’m really looking forward to working with MiDOG on my research project!”

Dr. Yaicha Peters, Animal Dermatology Clinic – San Diego

“As a proud collaborator with MiDOG, I deeply appreciate their dedication to fostering partnerships between industry and veterinary experts. Their commitment to enhancing diagnostic quality for veterinarians is commendable. In my experience, their support has been invaluable, earning them a ‘Double A+, Triple Star’ rating. Their assistance has been faultless, contributing significantly to the success of my projects and studies. I eagerly anticipate our continued collaboration.”

Dr. Richard Harvey, BVSc DVD DipECVD PhD FRSB FRCVS; European Specialist in Veterinary Dermatology

“We’re seeing that, if we prescribe too many antibiotics or they’re taken too frequently, animals are developing inappropriate or pathogenic strains of bacteria. We’re also seeing that our antibiotics are just not working against them anymore… It’s a good example of why we need better diagnostic testing, like MiDOG, so that we’re selecting the correct antibiotic every time our patients have an infection.”

Dr. Alissa Rexo, DVM, CVA, DACVD, Mid-Atlantic Veterinary Dermatology