Comparison of selected cytomorphological features of canine pemphigus foliaceus and superficial pyoderma.

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.

Histopathological characterisation of trunk-dominant canine pemphigus foliaceus, and comparison with classic facial and insecticide-triggered forms.

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 mm2 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.

A randomised, double-blinded comparison between subcutaneous rush and intralympathic allergen immunotherapy induction in atopic dogs.

BACKGROUND: Atopic dermatitis (AD) is one of the most common skin diseases in small animal practice. Allergen immunotherapy (AIT) is the only curative treatment for the disease, and oral, subcutaneous and intralymphatic administration of allergens are commonly employed. OBJECTIVES: To compare the efficacy of AIT following an induction phase with intralymphatic injections (ILIT) or rush immunotherapy (RIT). ANIMALS: Fifty privately owned dogs with AD. MATERIALS AND METHODS: In a double-blinded study, dogs were randomly assigned to either four monthly ILIT of allergen extract or RIT with five injections administered subcutaneously at hourly intervals on the first day. They were assessed by validated scores; Canine Atopic Dermatitis Lesion Index (CADLI) and pruritus Visual Analog Scale (PVAS) at the beginning of the study and after 1, 3, 6 and 12 months. The latter were performed daily for 7 days before each revisit. Medication scores and a total clinical score were calculated and compared between each group and time point. RESULTS: There was no significant difference in CADLI and PVAS scores, or CADLI and medication scores between groups at any of the time points. A significant improvement with both ILIT and RIT was seen in total and pruritus scores, respectively. An owner global assessment of good-to-excellent treatment efficacy was seen in 40% of the dogs; total scores improved by 27% and 35% in the RIT and ILIT group, respectively. Adverse effects were not seen. CONCLUSIONS AND CLINICAL RELEVANCE: Induction of AIT can be conducted either as RIT or ILIT with no loss in efficacy.

Reproducibility of serum testing for environmental allergen-specific IgE in dogs in Europe.

BACKGROUND: Serum testing for allergen-specific immunoglobulin (Ig)E is commonly employed to identify allergens used for allergen-specific immunotherapy in dogs, yet the reliability of results has been a matter of debate. OBJECTIVE: The aim of this study was to evaluate the reproducibility of serum tests for environmental allergen-specific IgE in three European laboratories. ANIMALS/METHODS: Serum was obtained from 33 client-owned dogs diagnosed with atopic dermatitis, divided into three aliquots and sent to the laboratories under different names. Two aliquots were sent simultaneously to one of the laboratories on the first day; the third sample was then sent to the same laboratory on the subsequent day. The laboratory for each patient was chosen according to a predetermined randomization list. The agreement between different samples from the same dog for each of the laboratories was calculated with a Cohen's Kappa test. Spearman's rank coefficients (rsp ) as well as the coefficients of variation (CV) additionally were calculated. RESULTS: The intra- and interassay agreements for laboratories A, B and C were 0.79 and 0.75, 0.92 and 0.90, and 0.90 and 0.85, respectively. The CVs were 18.92% and 22.95%, 14.43% and 18.79%, and 15.38% and 18.75% (respectively) and the rsp 0.73 and 0.68, 0.95 and 0.92, and 0.82 and 0.74 (respectively). CONCLUSION AND CLINICAL RELEVANCE: The differences in reproducibility between laboratories complicate test interpretation and underline the importance of interpreting results of serum testing for allergen-specific IgE in the context of the patient's clinical history.

Successful treatment of a mucous membrane pemphigoid in a young dog.

Mucous membrane pemphigoid was diagnosed in a 2.5-year-old male intact foxhound-beagle cross which was presented with an acute onset of non-pruritic, multifocal, slowly progressive erosive-ulcerative dermatitis predominantly affecting the nasal planum, eyelids and muzzle with multiple vesicles on the inner pinnae, oral mucosa and tongue. The diagnosis was based on clinical signs and histological examination of skin biopsies. The patient did not respond to immunosuppressive prednisolone therapy, but went into complete remission with oral doxycycline and niacinamide and stayed in remission on long-term exclusive niacinamide treatment.

[Successful treatment of a mucous membrane pemphigoid in a young dog]. / Erfolgreiche Behandlung eines mukokutanen Pemphigoids bei einem jungen Hund.

Mucous membrane pemphigoid was diagnosed in a 2.5-year-old male intact foxhound-beagle cross which was presented with an acute onset of non-pruritic, multifocal, slowly progressive erosive-ulcerative dermatitis predominantly affecting the nasal planum, eyelids and muzzle with multiple vesicles on the inner pinnae, oral mucosa and tongue. The diagnosis was based on clinical signs and histological examination of skin biopsies. The patient did not respond to immunosuppressive prednisolone therapy, but went into complete remission with oral doxycycline and niacinamide and stayed in remission on long-term exclusive niacinamide treatment.

Agreement of serum allergen test results with unblocked and blocked IgE against cross-reactive carbohydrate determinants (CCD) and intradermal test results in atopic dogs.

BACKGROUND: Tests for allergen-specific immunoglobulin E (IgE) are used to select allergens for immunotherapy in atopic dogs. Antibodies against cross-reactive carbohydrate determinants (anti-CCD IgE) have been identified in serum samples of atopic dogs. Their presence in humans is a known cause of clinically irrelevant polysensitization to plant allergens. OBJECTIVES: To compare the results of an intradermal test (IDT) and a serum test for allergen-specific IgE, with and without blocking anti-CCD IgE, before testing in dogs. ANIMALS: Thirty-one privately owned dogs with atopic dermatitis. METHODS AND MATERIALS: Dogs were prospectively skin tested and their serum samples were analysed for anti-CCD IgE. An Fc-ε receptor-based serum test for allergen-specific IgE was performed with and without blocking anti-CCD IgE. RESULTS: In dogs with negative anti-CCD IgE samples, the agreement between the results of the serum test and the IDT was substantial (κ = 0.71). Dogs with positive anti-CCD IgE samples (38.7%) showed no agreement between serum and skin testing (κ = -0.35), blocking anti-CCD IgE in those samples resulted in a fair agreement (κ = 0.43). Anti-CCD IgE positive sera had multiple positive results for grass and weed allergens, and blocking decreased them markedly. CONCLUSION AND CLINICAL IMPORTANCE: Intradermal testing agreed best with serum testing in dogs with no detectable anti-CCD IgE. Sera containing anti-CCD IgE had no agreement with IDT. Test agreement was improved by blocking the anti-CCD IgE. Apparent serum test polysensitization to plant allergens was associated with anti-CCD IgE.

Effect of an insect protein-based diet on clinical signs of dogs with cutaneous adverse food reactions. / Effekt eines Insektenprotein-basierten Futters auf die Symptomatik von futtermittelallergischen Hunden.

OBJECTIVE: Edible insects (like mealworms, locusts and crickets) contain energy, protein, fatty acids, minerals and trace elements and have been found to be high quality food sources. They could provide a new food source for patients with adverse food reactions, as well as being of ecological and ethical interest. The aim of this study was to evaluate the effect of a new commercially available, insect protein-based diet on the clinical signs in those dogs via Canine Atopic Dermatitis Lesion Index (CADLI), Pruritus Visual Analogue Scale (PVAS) and coat quality score. MATERIALS AND METHODS: A total of 20 dogs with atopic dermatitis due to previously diagnosed adverse food reaction were included in this study. This food was the only food fed to the patients for 2 weeks. RESULTS: The lesion score improved in 12 out of 20 dogs in. Only two dogs out of 15, which completed the study, showed mild deterioration of their lesions (on average by 1.5 CADLI points). One dog's skin lesions were unchanged. Pruritus could be reduced in eight patients but remained unchanged in four dogs. Two further patients deteriorated minimally (on average by 1.5 pruritus score points) and one dramatically (8 pruritus score points). The coat quality was only evaluated in 14 dogs. Six of 14 dogs showed an improvement in coat quality. The improvement of the lesion scores (Wilcoxon test, p = 0.007) and coat quality (Wilcoxon test, p = 0.01) was significant, there was no significant change in pruritus scores (p = 0.53). The palatability was very good the compatibility was except for one patient very good. CONCLUSION AND CLINICAL RELEVANCE: Based on these results, the investigated insect protein-based diet is an interesting alternative for dogs with food intolerance.

Atopic dermatitis in cats and dogs: a difficult disease for animals and owners.

The purpose of this review article is to give an overview of atopic dermatitis in companion animals and of recent developments including knowledge on immunological background, novel treatment options and difficulties in disease management. The prevalence of hypersensitivities seems to be increasing. The pathogenetic mechanisms are not fully understood, yet multiple gene abnormalities and altered immunological processes are involved. In dogs and cats, the diagnosis of atopic dermatitis is based on history, clinical examination and exclusion of other differential diagnoses. Intradermal testing or testing for serum allergen-specific Immunoglobulin E is only used to identify allergens for inclusion in the extract for allergen immunotherapy. Symptomatic therapy includes glucocorticoids, ciclosporin, essential fatty acids and antihistamines. A selective janus kinase 1 inhibitor and a caninized monoclonal interleukin-31 antibody are the newest options for symptomatic treatment, although longterm effects still need to be assessed. The chronic and often severe nature of the disease, the costly diagnostic workup, frequent clinical flares and lifelong treatment are challenging for owners, pets and veterinarians. Patience and excellent communication skills are needed to achieve a good owner compliance and satisfactory clinical outcome for the animal.