Search

Background: Cytological detection of acantholytic keratinocytes (acantholytic cells [AC]) helps to identify canine pemphigus foliaceus (cPF) yet AC also occurs in superficial pyoderma (SP), the main differential diagnosis., Hypothesis/objectives: To compare selected cytomorphological features of cPF and SP and to establish cytological diagnostic criteria that could differentiate cPF from SP., Animals: 40 and 51 client-owned dogs with PF and SP, respectively., Materials and Methods: Impression smears from cPF (64), impetigo (40) and exfoliative superficial pyoderma (ESP) (17) samples were stained with Romanowsky stain, randomised, blinded and evaluated by two investigators independently. The entire sample was screened (×500 or ×1000 magnification) for round (AC1), boat (AC2) and raft AC, eosinophils and bacteria. Interobserver agreements were calculated., Results: The average number of the 10 highest ×500 fields for AC1 and AC2 was significantly higher in PF than SP (p < 0.0001; Kruskal-Wallis test). Rafts and eosinophils were more common in PF than SP (p < 0.0001; chi-square test), while bacteria were rare in PF (5%; p < 0.0001; chi-square test). Observations between the experienced and novice investigators were highly correlated. An ROC analysis identified five AC1/×500-magnification field as a suitable cut-off value for predicting PF diagnosis. This cut-off value was tested by two additional investigators, who identified sensitivity of 84%-100%, specificity of 95%-97% and accuracy of 95%-96% for the diagnosis of cPF., Conclusions and Clinical Relevance: Criterion-based impression smear cytological evaluation can provide strong evidence to support the clinical diagnosis. Acantholytic cell morphology varies in cPF and SP, and experience can improve accuracy in cytological differentiation., (© 2024 The Author(s). Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of ESVD and ACVD.)

Successful treatment of pemphigus foliaceus (PF) often requires a multimodal therapeutic approach. The dog described herein underwent four therapeutic plasma exchange treatments for severe, refractory PF, resulting in a 50% reduction of lesional body surface area. This treatment option should be considered for the management of canine PF., (© 2023 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of ESVD and ACVD.)

Background: Oclacitinib (Apoquel; Zoetis) has been reported to be beneficial for treating immune-mediated disorders., Hypothesis/objectives: This retrospective study evaluates in which group of dogs [oclacitinib (OC) or azathioprine (AZ)] remission of pemphigus foliaceus (PF) was more effectively achieved with matched induction dosing of glucocorticoids; it further evaluates which group had a higher glucocorticoid-sparing effect., Animals: Review of 30 medical records of dogs diagnosed with PF presented to a private practice dermatological service., Materials and Methods: Retrospective analysis of dogs diagnosed with PF and treated with OC or AZ in combination with glucocorticoids., Results: There was no significant difference in the ability to induce remission between AZ and OC groups. In the AZ group, 13 of 15 dogs went into some type of remission (partial or complete), compared with 11 of 15 in the OC group. There was no significant difference between the two groups for the glucocorticoid-sparing effect. The AZ group had an average reduction of 77.9% from the induction glucocorticoid dose, and OC group had an average reduction of 64.4%. One of 15 patients in the AZ group and three of 15 patients in the OC group had a 100% reduction of the glucocorticoid dose., Conclusions and Clinical Relevance: These results indicate that OC can be considered as a treatment option for canine PF., (© 2023 ESVD and ACVD.)

Background: While the clinical features were described recently, the histopathological characterisation of trunk-dominant canine pemphigus foliaceus (PF) is lacking, and whether it differs from classic facial or insecticide-triggered PF is unknown., Hypothesis/objectives: This study describes the histopathological findings of trunk-dominant PF, and compares the results to classic facial and insecticide-triggered PF., Animals: Skin biopsies from 103 dogs with clinically characterised trunk-dominant (n = 33), classic facial (n = 26) and insecticide-triggered PF (n = 44) were included., Materials and Methods: Histological sections, randomised and blinded, were scored for over 50 morphological parameters of pustules, epidermis, dermis, adnexa and crusts. Intact pustule area and width were measured by digital microscopy., Results: In trunk-dominant PF, 77 intact pustules were predominantly subcorneal (0.0019-1.940 mm 2 area, 0.0470-4.2532 mm wide), and contained from one to over 100 acantholytic keratinocytes. Pustules had boat acantholytic cells, corneocytes, perinuclear eosinophilic rings, neutrophil rosettes, acantholytic cell necrosis, rafts, cling-ons and/or eosinophils. Peripustular epidermal spongiosis, necrosis and lymphocyte exocytosis occurred, as did follicular pustules. Mixed dermal inflammation often contained eosinophils. Trunk-dominant PF did not differ from the other PF groups except for few parameters, such as having fewer rafts (p = 0.003). Additional autoimmune inflammatory patterns occurred in all PF groups., Conclusions and Clinical Relevance: Trunk-dominant PF and other canine PF variants are histologically similar, which indicates shared pathomechanisms. The identification of common boat acantholytic cells and corneocyte separation has implications for the mechanisms of acantholysis. The diversity of histopathological and polyautoimmunity features support complicated immune mechanisms. Finally, results indicate that diagnostic biopsies cannot differentiate between these PF variants in dogs., (© 2023 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of ESVD and ACVD.)

Background: Canine trunk-dominant pemphigus foliaceus (PF) is mentioned rarely in the literature., Hypothesis/objectives: The goal of this study was to provide clinical description of trunk-dominant PF and to demonstrate the prevalence of serum antikeratinocyte, anti-desmocollin-1 (DSC1) and anti-desmoglein-1 (DSG1) antibodies, and determine their diagnostic value in this particular PF phenotype., Materials and Methods: Clinically relevant information was collected from 31, 25 and 34 dogs with trunk-dominant and facial PF and superficial pyoderma (SP), respectively. Sera from these dogs were tested for antikeratinocyte, anti-DSC1 and anti-DSG1 antibodies using indirect immunofluorescence on canine tissues and DSC1- and DSG1-transfected cells. Sera from healthy dogs and dogs with clinically irrelevant diseases served as controls., Results: Footpad involvement and grouped/polycyclic lesion organisation were identified as features of both PF phenotypes, and not of SP. Antikeratinocyte immunoglobulin (Ig)G was not specific for canine PF. By contrast, antigen-specific IgG was detected only in PF sera; anti-DSC1 IgG in 100% and 58% of dogs with facial and trunk-dominant PF, respectively, and anti-DSG1 IgG in 7% of dogs with trunk-dominant PF only., Conclusions: Trunk-dominant PF shares DSC1 as a major autoantigen with facial PF. The ability to detect anti-DSC1 IgG is lower in trunk-dominant PF, yet despite the lower sensitivity, the positive predictive value and accuracy of this particular anti-DSC1 IgG test are high. A negative test result, however, cannot exclude the diagnosis, and characteristic clinical features such as footpad involvement and/or grouped/polycyclic lesions must be considered when distinguishing trunk-dominant PF from its most relevant differential diagnosis: SP., (© 2022 ESVD and ACVD.)

Background: Goats are important worldwide as a source of milk, meat, fibre and hide, and as show animals and pets., Hypothesis/objectives: To document the type, signalment associations and prevalence of skin disease in a referral hospital population., Animals: Case population at a university veterinary teaching hospital., Methods and Materials: Retrospective study by searching computerised medical records of goats seen between 1 January 1988 and 1 January 2021. Key words employed were "alopecia, caseous lymphadenitis, Chorioptes, dermatitis, dermatophyte, dermatophytosis, goat, lice, louse, mange, mite, pemphigus foliaceus, Psoroptes, ringworm, seborrhea, skin" RESULTS: Of 1,488 records reviewed, 358 (24%) goats had skin disease recorded. Seventy-nine (22.1%) of 358 goats presented primarily for skin disease. The Nigerian Dwarf goat breed was at higher risk of developing skin disease (P < 0.0002). As goats aged, the odds for developing skin disease was higher [odds ratio (OR) = 1.07 per year, 95% confidence interval (1.04, 1.12)] as was the predilection for malignant skin tumours (P < 0.001). Sex was not associated with skin disease (P = 0.98). The most common clinical sign was exfoliative dermatitis, noted in 94 (26.4%) of 358 goats. The most common diagnoses were pediculosis, bacterial skin disease and squamous cell carcinoma. Less frequent diagnoses were Chorioptes spp. infestation, contagious ecthyma (orf), coronitis/interdigital dermatitis, demodicosis, dermatophytosis, Psoroptes spp. infestation, dermatophilosis and pemphigus foliaceus., Conclusions and Clinical Importance: Skin diseases are common in goats. Nigerian Dwarf goats and older goats are at greater risk of developing skin disease; Nigerian Dwarf goats had a predilection for malignant skin tumours. Clinicians should include a dermatological examination in goats regardless of the reason for presentation., (© 2021 ESVD and ACVD.)

Pemphigus vulgaris is a rare immune-mediated skin disorder of the dog, usually treated with immunosuppressive medications such as oral glucocorticoids, azathioprine or ciclosporin. Herein we report the successful treatment of pemphigus vulgaris in a dog, using oclacitinib and a topical product containing fucidic acid (0.5 % w/w) and betamethasone valerate., (© 2022 ESVD and ACVD.)

Background: Oral mycophenolate mofetil (MMF) currently is considered a low-risk steroid-sparing therapeutic option for the management of canine pemphigus foliaceus (PF)., Objectives: This retrospective study evaluates the therapeutic outcomes of dogs with PF treated with the combination of oral MMF and glucocorticoid (GC). Clinical outcomes and adverse side effects are reported., Animals: Eleven dogs diagnosed with PF., Materials and Methods: Retrospective review of medical records from dogs presented with PF to the dermatology service of a veterinary teaching hospital between 2015 and 2020., Results: Eleven dogs were identified which had received concurrent GCs and MMF. The MMF dose range was 19.8-45 mg/kg/day. Only two dogs (two of 11) treated with a mean MMF dosage of 39 mg/kg/day along with oral prednisone or dexamethasone achieved complete remission (CR). Partial remission (PR) was achieved in four of 11 dogs who received either prednisone, prednisolone or dexamethasone along with MMF (mean dosage 26 mg/kg/day). Four dogs (four of 11) showed poor response to MMF given at 28.5 mg/kg/day along with prednisone or dexamethasone. In one dog (one of 11) MMF was discontinued due to severe GI upset; transient vomiting and diarrhea was observed in four of 11 dogs. The median duration of MMF therapy in conjunction with GC for all groups was 70.5 days. Tapering of oral GCs while continuing MMF administration at the same dosage and frequency led to recurrence of lesions in all PF patients., Conclusion: Oral MMF combined with GC achieved CR in two of 11 PF dogs included in this study. Further research of MMF efficacy in PF may need to be performed., (© 2021 ESVD and ACVD.)

Autoimmune blistering diseases (AIBDs) are a heterogenous group of skin conditions, broadly classified into two categories depending on the location of blister formation: intraepidermal blistering in the pemphigus group and subepidermal blistering in the pemphigoid group. Although AIBDs occur in both humans and animals, the arsenal of data for human AIBDs far exceeds those of their animal counterpart. Therefore, the main purpose of this review is to highlight existing knowledge, and recent advances in the diagnosis and management of AIBDs in humans - to serve as a road map for veterinary dermatologists. AREAS COVERED: Recent findings include complement-independent pathways in the pathogenesis of bullous pemphigoid, as well as the role of desmoglein and desmocollin autoantibodies in inducing acantholysis. Systemic glucocorticoids are the mainstay of treatment for AIBDs in humans, yet their long-term use is associated with severe adverse effects and complications, thereby limiting their use. Therefore, researchers have been exploring new and safer alternative therapeutic options for human AIBDs such as anti-CD20 monoclonal antibodies (Rituximab), Bruton's tyrosine kinase inhibitors (BTKi) and neonatal Fc receptor (FcRn) blockers. EXPERT OPINION: Randomised controlled trial (RCT) level evidence show that Rituximab and short-course GC regimes are more effective and safer than traditional GC treatment for human AIBDs. FcRn blockers such as SYNT001 have shown positive results in preliminary phase 2 clinical trials for treatment of human pemphigus; further trials are required. Rilzabrutinib (PRN1008), an orally administered BTKi, has recently completed phase 2 trials in pemphigus and is in a phase 3 RCT in humans., (© 2021 ESVD and ACVD.)

Background: Concurrent vasculopathic lesions in dogs with pemphigus foliaceus (PF) have been observed anecdotally yet not reported in the literature. Any association with prognosis is unclear., Hypothesis/objectives: To compare clinical features and outcome of PF in dogs with and without vasculopathic lesions., Animals: Archived, formalin-fixed, paraffin-embedded biopsy samples of 41 dogs with PF., Methods and Materials: Archived, formalin-fixed, paraffin-embedded biopsy samples with a histological diagnosis of PF were selected and re-evaluated independently. Dogs were assigned to groups following histological evaluation: Group 1 (no vasculopathic lesions) and Group 2 (vasculopathic lesions present). Group 2 was subdivided into Group 2a (vasculopathic lesions without vasculitis - i.e. vasculopathy) and Group 2b (overt vasculitis). Medical records from identified cases were reviewed retrospectively for data on clinical presentation, treatment and outcome., Results: Time to remission was longer in Group 2b (93.8 days) compared to Group 1 (41.8 days) (P = 0.047). Dogs in groups 2a and 2b were more likely to have systemic signs of illness at presentation (P = 0.028 and P = 0.032, respectively) compared to Group 1. Dogs in Group 2b were more likely to have adverse effects associated with treatment than dogs in Group 1 (P = 0.004). There were no significant differences in lesion type, distribution, rates of remission, recurrence or corticosteroid dosage between groups., Conclusions and Clinical Importance: Dogs with PF and concurrent vasculitis took longer to achieve remission and were more likely to have systemic signs of illness or adverse effects associated with treatment than dogs with PF without concurrent vasculopathic lesions., (© 2021 the European Society of Veterinary Dermatology and the American College of Veterinary Dermatology.)

Pemphigus foliaceous (PF) is a pustular, immune-mediated skin disease characterised by acantholytic cells and commonly treated with high doses of glucocorticoids. This report describes one case of feline PF successfully controlled using oral oclacitinib, suggesting a possible therapeutic alternative to glucocorticoids in some cases., (© 2021 ESVD and ACVD.)

Background: Bruton's tyrosine kinase (BTK) is important in B-cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is one of the most common canine autoimmune skin diseases., Objectives: To determine the safety and efficacy of the BTKi PRN1008 in the treatment of cPF., Animals: Four privately owned dogs., Methods and Materials: Four dogs diagnosed with PF were administered BTKi PRN1008. Initial dosages approximated to 15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for 20 weeks, attempting to decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels and urinalyses, and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Serum anti-desmocollin-1 (DSC-1) and desmoglein-1 (DSG-1) immunoglobulin (Ig)G titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells (PBMC)., Results: All four dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. Three dogs continued to improve and sustained near complete remission by 20 weeks, at which point three responses were considered "good" and one "fair". Final daily dosages were in the range 17-33 mg/kg. Anti-DSC-1 IgG titre decreased dramatically in one dog, was undetectable in two and was uninterpretable in one dog. No dogs had detectable IgG to DSG1. A possible adverse event occurred in one dog., Conclusions and Clinical Importance: BTKi PRN1008 monotherapy may have some beneficial effects in some cases of cPF., (© 2020 ESVD and ACVD.)

Background: Circulating anti-keratinocyte immunoglobulin (Ig)G targeting desmosomal proteins have been identified in people and dogs with pemphigus foliaceus (PF). By contrast, detection attempts in PF-affected cats have been largely unsuccessful., Hypothesis/objectives: To detect circulating anti-keratinocyte autoantibodies in PF-affected cats and determine their titres and tissue-staining patterns., Animals: Thirty PF-affected cats were compared to 11 specific-pathogen free, 15 healthy and 31 allergic cats., Methods and Materials: Sera were tested by indirect immunofluorescence on canine footpad and buccal mucosal substrates., Results: Circulating, anti-keratinocyte IgG with a suprabasilar, web-like (intercellular) pattern were detected in the majority of PF-affected cats (23 of 30, 77%), some allergic cats (six of 31, 19%) and one healthy cat (7%). Both footpad epidermis and buccal mucosa were positive in the majority of seropositive PF-affected cats (21 of 23, 91%), and in only one of six (17%) seropositive allergic cats. Staining was limited to the footpad in the remaining seropositive PF-affected and allergic cats and one seropositive healthy cat. Reciprocal IgG titres were significantly higher in PF-affected cats compared to controls (Dunn's post-test, P < 0.0001). Anti-keratinocyte IgM, IgA or IgE were not detected in any sera., Conclusions and Clinical Importance: These results confirm the presence of circulating anti-keratinocyte IgG in a majority of PF-affected cats and in a small percentage of healthy and allergic cats. Although the molecular target and pathogenic nature of the antibodies remains unknown, the detection of positive immunostaining on buccal mucosal tissue, in addition to the footpad, suggests that the major target antigen of feline PF differs from that reported in dogs., (© 2020 ESVD and ACVD, Veterinary Dermatology.)

Background: Polyautoimmunity, the concurrent expression of two or more distinct autoimmune diseases (ADs) in a single individual, is a known phenomenon in humans and has been rarely reported in dogs. To the best of the authors' knowledge, comorbid pemphigus foliaceus (PF) and generalized discoid lupus erythematosus (GDLE) has not been reported in dogs., Hypothesis/objectives: To describe the clinical, histological and immunological features and treatment outcome of two unrelated dogs with comorbid PF and GDLE., Animals: One 10-year-old, spayed German shepherd dog and one 8-year-old, castrated American Staffordshire terrier presented for evaluation of a symmetrical, facial- and/or pedal-dominant pustular dermatitis with concurrent, truncal scaly plaques., Methods: For each dog, clinicopathological characterization included physical examination, lesion cytological evaluation, bacterial culture and sensitivity testing, skin histopathological investigation and direct and indirect immunofluorescence testing. Additional diagnostic imaging and haematological testing was performed to exclude extracutaneous disease., Results: Both dogs exhibited lesions clinically and histologically compatible with PF and GDLE. Moreover, one dog exhibited generalized leucotrichia and chronic superficial keratitis. Remission was achieved with immunosuppressive dosages of prednisolone [high-dose pulse (Case 1) or standard immunosuppressive dosage (Case 2)] and ciclosporin (5-6 mg/kg/day). Tissue-bound antikeratinocyte immunoglobulin (Ig)G and IgM were detected in both dogs. A weak basement membrane zone deposit of C3 was seen in one dog. Circulating antikeratinocyte and anti-desmocollin-1 IgG were detected in one dog., Conclusions and Clinical Importance: Cutaneous polyautoimmunity can occur in the dog. Depending on the specific disease combinations, overlapping clinical features may present diagnostic and/or therapeutic challenges. Moreover, these cases should be monitored for development of additional cutaneous or extra-cutaneous AD(s)., (© 2020 ESVD and ACVD.)

Background: Bruton's tyrosine kinase (BTK) is important in B-cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is the most common canine autoimmune skin disease., Objectives: To determine the safety and efficacy of a BTKi in cPF treatment., Animals: Nine privately owned dogs., Methods and Materials: Nine dogs diagnosed with PF were administered BTKi PRN473. Initial dosages were ≈15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for a maximum of 20 weeks, attempting decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels, urinalyses and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Anti-desmocollin-1 (DSC-1) and desmoglein-1 (DSG-1) immunoglobulin G (IgG) titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells., Results: All nine dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. At the end of the study, four responses were considered "good", two "fair", two "poor" and one dog withdrawn due to recurrence of a previously excised mast cell tumour. Four dogs continued to improve by Week 4; three sustained near complete remission by study's end. The anti-DSC-1 IgG titre decreased in three dogs, increased in two, was undetected in three and was not performed in the withdrawn dog. No dogs had detectable IgG to DSG1. Possible adverse effects occurred in three dogs., Conclusions and Clinical Importance: Bruton's tyrosine kinase inhibitor monotherapy may have beneficial effects in some cases of cPF., (© 2020 ESVD and ACVD.)

Background: Few studies have described the pathophysiology, clinical course, treatment outcomes and quality of life (QoL) of cats with pemphigus foliaceus (PF)., Objective: Describe clinicopathological features, treatment outcomes and impacts on QoL in feline PF., Animals: Forty-nine client-owned cats with PF that presented to a veterinary teaching hospital between 1987 and 2017., Methods and Materials: Medical records and histopathological reports were reviewed to obtain clinicopathological data and treatment outcomes. Owners were contacted and requested to complete a questionnaire to obtain long-term follow-up and evaluate the impacts of PF on QoL of cats and owners., Results: Domestic short/medium/long hair breeds were most commonly affected, with pinnae, head, haired face, nasal planum and ungual folds most frequently involved. Associated pruritus and systemic signs of illness were common. Vasculopathological changes were noted in a small proportion of cats. Corticosteroid monotherapy was sufficient to induce complete remission in the majority of cats. Pemphigus foliaceus and its management had a negative impact on QoL of both cats and owners. Receiving/administering medications, attending veterinary appointments, and financial and time commitments were cited sources of stress for affected cats and/or owners., Conclusions and Clinical Importance: Results illustrate that affected cats generally respond favourably to treatment but do require long-term therapy. The exact aetiology of the vasculopathological changes was unclear; it may reflect the stage or severity of disease or suggest the presence of a cutaneous adverse drug reaction. Clinicians managing cats with PF should be aware of the potential negative impact on QoL of owners and cats and adjust management accordingly., (© 2019 ESVD and ACVD.)