Vet Dermatol 2014; 25: 273–274
DOI: 10.1111/vde.12161
Editorial Veterinary dermatology and dermatopathology It is a fact and a clinical conundrum that very different diseases can present with a similar clinical appearance, and therefore the contribution of diagnostic pathology is critical to the evolution of medical knowledge and practice. At the same time, interpretation of the significance of microscopic findings and separation of disease entities with similar patterns of microscopic change must be informed by the clinical features of the disease. Communication between the clinician and the pathologist is therefore essential. As the body of knowledge in veterinary medicine has exploded, we have seen the development of specialties in clinical practice. Subspecialization of veterinary pathologists is also a natural development of this knowledge explosion, because it is unreasonable to expect all pathologists to have a high level of expertise in the examination of all tissues from all species and the corollary of myriad clinical conditions and specific diseases that the microscopic changes signify. Perhaps nowhere is this more evident than in the practice of veterinary dermatopathology, which has grown with as well as supported the growth of the clinical specialty of veterinary dermatology. In the first issue of Veterinary Dermatology, the journal published a review of pododermatitis by Stephen D. White that is reprinted in this anniversary issue. From many possible examples, I selected this paper to illustrate the importance of the relationship between dermatologists and dermatopathologists in the diagnosis of skin diseases in veterinary medicine. When White’s review was published, the field of veterinary dermatopathology was, to quote Bob Dunstan, ‘still in its infancy’.1 The specialty of veterinary dermatology, while no longer an infant, was also young, having been recognized by the American Veterinary Medical Association in 1984. Since then, there has been considerable advancement in our recognition of different diseases in terms of clinical presentation and progression, diagnosis and pathogenesis. This advancement has been fuelled by the dedication of pioneering dermatologists and pathologists in the fields of dermatology and dermatopathology, and turbo-injected with the founding of the International Society for Dermatopathology in 1998. The resulting advances in our knowledge base translate into improved outcomes for our patients. Yet diseases of the skin, including the pedal dermatoses, comprise a complex group of disorders, within which are presentations that may confound our best combined efforts, underscoring the need for continued research and clinical collaboration. Some things change and some things stay the same. Infections still play a significant role in pododermatitis, and to a large degree, our understanding of the bacterial component of pododermatitis is relatively unchanged. © 2014 ESVD and ACVD, Veterinary Dermatology, 25, 273–274.
However, treatment of bacterial dermatitis, whether primary or secondary, is greatly complicated by the emergence and increasing prevalence of meticillin-resistant and multidrug-resistant strains of Staphylococcus species. Principles of antimicrobial stewardship also require us to reconsider the prescription of lifelong antibiotic therapy as a treatment for chronic pododermatitis/pyoderma. In addition to the role of antimicrobial therapy in driving the development of resistant strains, there has been evolution in our understanding and appreciation of the microbiome as a component of overall health and therefore an emphasis on limiting the use of antimicrobials to the extent feasible. Biopsy, cultures and correlation of results with the clinical presentation are therefore of increased importance in management of these difficult cases, as is ongoing research that will allow us better to understand and treat or prevent underlying diseases. Several distinct as well as overlapping presentations of interdigital pyoderma with furunculosis are now recognized. A specific syndrome of interdigital palmar and plantar comedones was first reported in this journal in 2008. For other forms of interdigital furunculosis, in addition to the potential contributions of allergy, endocrine disease and demodicosis, there is now increased understanding of the potential roles of conformation and obesity in the development of these lesions. Both clinical and microscopic features can provide important clues, and often it is the correlation of these that results in the accurate diagnosis and therefore correct treatment of these cases. Some of the infectious diseases covered in White’s review2 are now seen more commonly, as a result of increased use of immunosuppressive chemotherapy in veterinary medicine, including but not limited to the treatment of cutaneous autoimmune diseases and allergic dermatitis; for example, we see more cases of disseminated fungal dermatitis resulting from opportunistic infection with saprophytic fungi in dogs receiving ciclosporin. With other infectious diseases, such as leishmaniosis and pythiosis, we have seen an increase in geographical distribution due to global travel and climate change, and dermatologists and pathologists in regions where the diseases are not or have not traditionally been endemic need to be aware of the clinical presentation and microscopic findings, appropriate ancillary methods and sample requirements for recognition and confirmation of these diseases. Sterile pyogranuloma/granuloma syndrome is still a frequent diagnosis in canine patients and less frequently in feline patients and may present with pedal involvement, as described by White.2 Also in the category of chronic and apparently sterile pododermatitis is the distinctive and considerably less common syndrome of plasmacellular inflammation limited to the paw pads, or plasma cell pododermatitis. We still refer to these diseases as sterile, though this is sometimes qualified by placing sterile in 273
Editorial
quotation marks to indicate our scepticism. Yet to date, in spite of advances in molecular methods for identification of infectious agents in tissues, evidence to support reclassification of these highly inflammatory, steroidresponsive lesions as nonsterile is lacking. Thallium toxicity and generic dog food dermatosis are now rare or historic diseases, while White’s review2 makes no mention of epitheliotropic cutaneous T-cell lymphoma and vasculitis, both of which are now recognized as important differential diagnoses for paw pad lesions. Hepatocutaneous syndrome, or superficial necrolytic dermatitis, is somewhat better characterized than at the time of White’s review, but still poorly understood. These changes in disease prevalence or presentation, recognition of new diseases and continuing gaps in our understanding of old diseases underscore the importance of the ongoing work of clinicians, pathologists and researchers involved in the study of cutaneous and systemic disease. Indeed, the opportunities for interdisciplinary collaboration are tremendous, but must be grounded in the clinical and microscopic characterization of the diseases if they are to translate into advances in understanding that are relevant to the clinical practice of dermatology, and thus to improvements in the diagnosis and treatment of disease.
274
Essential elements in the advancement of medical knowledge are communication and collaboration; sharing findings, asking questions and pooling knowledge obtained in clinics, at the microscope and at the research bench. Veterinary Dermatology serves a vital role by promoting the value of these relationships and by providing a professional forum for exchange of information between clinical dermatologists, diagnostic dermatopathologists and researchers involved in the investigation of skin diseases in animals. These are the relationships that power our forward momentum. Jennifer G. Ward Specialty VETPATH, 14810 15th Avenue NE, Shoreline, WA 98155, USA
References 1. Dunstan RW. A user’s guide to veterinary surgical pathology laboratories. Or, why do I still get a diagnosis of chronic dermatitis even when I take a perfect biopsy? Vet Clin North Am: Small Anim Pract 1990; 20: 1397–1417. 2. White SD. Pododermatitis. Vet Dermatol 1990; 1: 1–18.
© 2014 ESVD and ACVD, Veterinary Dermatology, 25, 273–274.
DOI: 10.1111/vde.12161
Editorial Veterinary dermatology and dermatopathology It is a fact and a clinical conundrum that very different diseases can present with a similar clinical appearance, and therefore the contribution of diagnostic pathology is critical to the evolution of medical knowledge and practice. At the same time, interpretation of the significance of microscopic findings and separation of disease entities with similar patterns of microscopic change must be informed by the clinical features of the disease. Communication between the clinician and the pathologist is therefore essential. As the body of knowledge in veterinary medicine has exploded, we have seen the development of specialties in clinical practice. Subspecialization of veterinary pathologists is also a natural development of this knowledge explosion, because it is unreasonable to expect all pathologists to have a high level of expertise in the examination of all tissues from all species and the corollary of myriad clinical conditions and specific diseases that the microscopic changes signify. Perhaps nowhere is this more evident than in the practice of veterinary dermatopathology, which has grown with as well as supported the growth of the clinical specialty of veterinary dermatology. In the first issue of Veterinary Dermatology, the journal published a review of pododermatitis by Stephen D. White that is reprinted in this anniversary issue. From many possible examples, I selected this paper to illustrate the importance of the relationship between dermatologists and dermatopathologists in the diagnosis of skin diseases in veterinary medicine. When White’s review was published, the field of veterinary dermatopathology was, to quote Bob Dunstan, ‘still in its infancy’.1 The specialty of veterinary dermatology, while no longer an infant, was also young, having been recognized by the American Veterinary Medical Association in 1984. Since then, there has been considerable advancement in our recognition of different diseases in terms of clinical presentation and progression, diagnosis and pathogenesis. This advancement has been fuelled by the dedication of pioneering dermatologists and pathologists in the fields of dermatology and dermatopathology, and turbo-injected with the founding of the International Society for Dermatopathology in 1998. The resulting advances in our knowledge base translate into improved outcomes for our patients. Yet diseases of the skin, including the pedal dermatoses, comprise a complex group of disorders, within which are presentations that may confound our best combined efforts, underscoring the need for continued research and clinical collaboration. Some things change and some things stay the same. Infections still play a significant role in pododermatitis, and to a large degree, our understanding of the bacterial component of pododermatitis is relatively unchanged. © 2014 ESVD and ACVD, Veterinary Dermatology, 25, 273–274.
However, treatment of bacterial dermatitis, whether primary or secondary, is greatly complicated by the emergence and increasing prevalence of meticillin-resistant and multidrug-resistant strains of Staphylococcus species. Principles of antimicrobial stewardship also require us to reconsider the prescription of lifelong antibiotic therapy as a treatment for chronic pododermatitis/pyoderma. In addition to the role of antimicrobial therapy in driving the development of resistant strains, there has been evolution in our understanding and appreciation of the microbiome as a component of overall health and therefore an emphasis on limiting the use of antimicrobials to the extent feasible. Biopsy, cultures and correlation of results with the clinical presentation are therefore of increased importance in management of these difficult cases, as is ongoing research that will allow us better to understand and treat or prevent underlying diseases. Several distinct as well as overlapping presentations of interdigital pyoderma with furunculosis are now recognized. A specific syndrome of interdigital palmar and plantar comedones was first reported in this journal in 2008. For other forms of interdigital furunculosis, in addition to the potential contributions of allergy, endocrine disease and demodicosis, there is now increased understanding of the potential roles of conformation and obesity in the development of these lesions. Both clinical and microscopic features can provide important clues, and often it is the correlation of these that results in the accurate diagnosis and therefore correct treatment of these cases. Some of the infectious diseases covered in White’s review2 are now seen more commonly, as a result of increased use of immunosuppressive chemotherapy in veterinary medicine, including but not limited to the treatment of cutaneous autoimmune diseases and allergic dermatitis; for example, we see more cases of disseminated fungal dermatitis resulting from opportunistic infection with saprophytic fungi in dogs receiving ciclosporin. With other infectious diseases, such as leishmaniosis and pythiosis, we have seen an increase in geographical distribution due to global travel and climate change, and dermatologists and pathologists in regions where the diseases are not or have not traditionally been endemic need to be aware of the clinical presentation and microscopic findings, appropriate ancillary methods and sample requirements for recognition and confirmation of these diseases. Sterile pyogranuloma/granuloma syndrome is still a frequent diagnosis in canine patients and less frequently in feline patients and may present with pedal involvement, as described by White.2 Also in the category of chronic and apparently sterile pododermatitis is the distinctive and considerably less common syndrome of plasmacellular inflammation limited to the paw pads, or plasma cell pododermatitis. We still refer to these diseases as sterile, though this is sometimes qualified by placing sterile in 273
Editorial
quotation marks to indicate our scepticism. Yet to date, in spite of advances in molecular methods for identification of infectious agents in tissues, evidence to support reclassification of these highly inflammatory, steroidresponsive lesions as nonsterile is lacking. Thallium toxicity and generic dog food dermatosis are now rare or historic diseases, while White’s review2 makes no mention of epitheliotropic cutaneous T-cell lymphoma and vasculitis, both of which are now recognized as important differential diagnoses for paw pad lesions. Hepatocutaneous syndrome, or superficial necrolytic dermatitis, is somewhat better characterized than at the time of White’s review, but still poorly understood. These changes in disease prevalence or presentation, recognition of new diseases and continuing gaps in our understanding of old diseases underscore the importance of the ongoing work of clinicians, pathologists and researchers involved in the study of cutaneous and systemic disease. Indeed, the opportunities for interdisciplinary collaboration are tremendous, but must be grounded in the clinical and microscopic characterization of the diseases if they are to translate into advances in understanding that are relevant to the clinical practice of dermatology, and thus to improvements in the diagnosis and treatment of disease.
274
Essential elements in the advancement of medical knowledge are communication and collaboration; sharing findings, asking questions and pooling knowledge obtained in clinics, at the microscope and at the research bench. Veterinary Dermatology serves a vital role by promoting the value of these relationships and by providing a professional forum for exchange of information between clinical dermatologists, diagnostic dermatopathologists and researchers involved in the investigation of skin diseases in animals. These are the relationships that power our forward momentum. Jennifer G. Ward Specialty VETPATH, 14810 15th Avenue NE, Shoreline, WA 98155, USA
References 1. Dunstan RW. A user’s guide to veterinary surgical pathology laboratories. Or, why do I still get a diagnosis of chronic dermatitis even when I take a perfect biopsy? Vet Clin North Am: Small Anim Pract 1990; 20: 1397–1417. 2. White SD. Pododermatitis. Vet Dermatol 1990; 1: 1–18.
© 2014 ESVD and ACVD, Veterinary Dermatology, 25, 273–274.
