Immunopathogenesis of the feline atopic syndrome

Performance of applications of Ophytrium-containing mousse with or without shampoo in cats with pruritic and irritated skin: a multicentre prospective field trial

OBJECTIVES

This study aimed to evaluate the performance of a protocol in which topical products (DOUXO S3 CALM Shampoo and Mousse; Ceva Santé Animale) containing Ophytrium were applied to cats to help manage feline atopic syndrome (FAS).

METHODS

A total of 23 client-owned cats with a history of FAS and presenting irritated skin and pruritus were recruited for this study. The cats were either shampooed or moussed on day 0 (D0) and then moussed every 48-72 h for 3 weeks. On D0, D7 and D21, clinical signs were assessed using the validated scoring system, Scoring Feline Allergic Dermatitis (SCORFAD). Pruritus was graded by the owner using an adapted dual visual analogue scale (Pruritus Visual Analog Scale for Cats [VAScat]). Veterinarians also assessed pruritus intensity and frequency, and provided a subjective assessment of global skin condition and of improvements in each cat's condition. On D21, all questionnaires were collected from both veterinarians and owners.

RESULTS

Among the 19 cats that completed the study, the SCORFAD and VASmax (maximum value of VAScat, either scratching or licking) scores improved by ⩾50% in 63.2% and 38.9% of animals, respectively. Mean SCORFAD values decreased significantly between D0 and D21 (from 6.2 to 2.8, P <0.05). Similarly, mean VASmax values decreased significantly between D0 and D21 (from 7.4 to 4.3, P <0.05). Overall, veterinarians assessed the improvement as satisfactory, good or excellent in 18/19 (94.7%) cases. The protocol was considered efficient and practical by 18/19 (94.7%) and 19/19 (100%) owners, respectively, and the resulting good condition of skin and coat was emphasised by 15/19 (78.9%) owners.

CONCLUSIONS AND RELEVANCE

This topical protocol with Ophytrium-containing mousse and shampoo was well tolerated. The products were effective in reducing skin irritation and discomfort quickly and significantly in cats with skin irritation and pruritus, yielding high satisfaction levels among both veterinarians and owners.

Comparison of intradermal and serum testing for environmental allergen-specific immunoglobulin E determination in a laboratory colony of cats with naturally acquired atopic syndrome

BACKGROUND

Allergen testing is used to select antigens included in the desensitisation vaccine. Intradermal skin test (IDT) is the gold standard in cats, yet allergen-specific immunoglobulin (Ig)E serological testing (ASIS) is often used. Feline data are lacking regarding the agreement between IDT and ASIS results.

HYPOTHESIS/OBJECTIVES

The first objective of the study was to establish a colony of cats with naturally acquired feline atopic syndrome (FAS). Further objectives were to define their hypersensitivity disorder to detail the allergen tests results, and to assess similarity between the allergen tests.

ANIMALS

Thirty-five cats with FAS and 10 control cats.

MATERIALS AND METHODS

Enrolled cats went through a five phase-screening and quarantine process before joining the colony. An elimination diet trial was performed on all FAS cats. ASIS and IDT were consecutively performed on all cats under sedation.

RESULTS

Reactions to 34 allergens were compiled for the 45 cats. Global sensitivity and specificity of ASIS were 34.7% and 78.9%, respectively. Only flea (ICC = 0.26, p = 0.040) and Dermatophagoides pteronyssinus (ICC = 0.48, p < 0.001) allergens had a significant intraclass correlation (weak agreement). Two FAS cats had negative tests including one cat with a concomitant food allergy.

CONCLUSIONS AND CLINICAL RELEVANCE

This study depicts the first reported colony of cats with naturally acquired FAS. This is the first feline study to compare and show the poor agreement between allergen tests with a panel of 34 allergens. This colony also harbours two cats with FAS with negative allergen tests. These may represent the first described cats with an intrinsic form of atopic syndrome.

Transcriptome analysis of selected cytokine and chemokines in the eosinophilic plaques of cats with atopic skin syndrome

BACKGROUND

Previous evaluations of cytokine and chemokine gene expressions [messenger (m)RNA] in the skin of allergic cats were mostly unsuccessful in detecting the T-helper 2 (Th2) pathway, which is associated with the major effector cytokines interleukin (IL)-4, IL-5 and IL-13.

HYPOTHESIS/OBJECTIVE

To evaluate differences in the mRNA expression in eosinophilic plaques of cats diagnosed with feline atopic skin syndrome (FASS) compared to healthy controls.

ANIMALS

Four client-owned cats with FASS with eosinophilic plaques and five healthy control cats.

MATERIALS AND METHODS

Gene expressions (mRNA) of 14 cytokines and chemokines from eosinophilic plaque skin of cats with FASS and site-matched skin samples from healthy controls were analysed using quantitative reverse-transcription PCR analysis.

RESULTS

Eosinophilic plaques were characterized by upregulation of Th2 cytokines IL-4 (p ≤ 0.01), IL-5 (p ≤ 0.01) and IL-13 (p ≤ 0.01) and Th2-attracting chemokine CCL17 (p ≤ 0.05). Moreover, there was higher expression of S100 calcium-binding protein A 8 (p ≤ 0.01) as well as C-X-C Motif chemokine ligand 10 (CXCL10; p ≤ 0.01), IL-10 (p ≤ 0.05) and the Th17 cytokine IL-17A (p ≤ 0.01) in lesional skin compared to healthy samples. There was no difference in gene expressions of IL-12A, IL-31, IL-33, thymic stromal lymphopoietin (TSLP), tumour necrosis factor-α (TNF-α) or CCL5.

CONCLUSIONS AND CLINICAL RELEVANCE

Results demonstrate that eosinophilic plaques feature dominant Th2 and IL-17A inflammatory responses in the skin. Further larger-sample transcriptome studies are needed to advance our understanding of the pathogenesis of different skin lesions in FASS.

Efficacy of oclacitinib for the control of feline atopic skin syndrome: correlating plasma concentrations with clinical response

OBJECTIVES

The aim of this study was to assess the efficacy of a new therapeutic regimen of oclacitinib for the control of feline atopic skin syndrome (FASS) and to correlate plasma levels of this drug with clinical effects.

METHODS

Twenty-eight client-owned cats with a clinical diagnosis of FASS were recruited. Oclacitinib was administered at 1 mg/kg q12h for 2 weeks and then at 1 mg/kg q24h for a further 2 weeks. At the study outset (D0), and 7 (D7) and 28 (D28) days after starting treatment, clinical lesions were assessed using a validated scoring system (SCORing Feline Allergic Dermatitis [SCORFAD]) and pruritus was graded via an adapted visual analogue scale (PVAS). At the same time points, plasma oclacitinib levels and haematological variables were measured.

RESULTS

Among 18 cats completing the study, PVAS and SCORFAD improved by ⩾50% in 61% and 88% of animals, respectively. Mean PVAS decreased significantly between D0 and D7 and between D0 and D28 (both P <0.001) but not between D7 and D28. Likewise, mean SCORFAD values decreased significantly between D0 and D7 and between D0 and D28 (both P <0.001) but not between D7 and D28. On D7 and D28, plasma oclacitinib concentrations varied widely from 0 to 1443.2 ng/ml and from from 0 to 1177.7 ng/ml, respectively. Oclacitinib concentrations showed no correlation with clinical effects (SCORFAD and PVAS).

CONCLUSIONS AND RELEVANCE

Oclacitinib emerged as being safe and effective to control clinical signs of FASS. A mean dose of 1 mg/kg, even without extending twice-daily treatment beyond the first 2 weeks, could be a suitable therapeutic regimen. Plasma drug levels did not seem useful to predict clinical response during treatment.

An unusual case of eosinophilic uveitis in a cat

An 8-year-old female spayed domestic short-haired cat was examined for recurrent unilateral anterior uveitis of 5 month's duration. No underlying cause was found on infectious disease screening. The cat also had a 4-year history of allergic or immune-mediated skin disease that was controlled with corticosteroid injections followed by long-term oral cyclosporine therapy. Medical management with frequent topical anti-inflammatory drugs (prednisolone acetate 1% suspension, diclofenac 0.1% solution) controlled the intraocular inflammation; however, the uveitis would relapse when therapy was discontinued. Eventually, secondary glaucoma developed OD and the eye was enucleated. At the time of surgery, a complete blood count showed a mild eosinophilia. Histopathology revealed a marked panuveitis characterized by an abundant accumulation of mixed inflammatory cells, with a predominantly eosinophilic infiltrate in the anterior chamber, iris, ciliary body, and choroid. No etiologic agents were found on serial sections, and there were no cellular criteria for malignancy noted. Nine months after enucleation, the chronic dermatitis appeared to be in remission despite no further medical management. This is the first known report of a primarily eosinophilic uveitis in a cat with chronic allergic skin disease and may be considered an ocular variant of feline eosinophilic granuloma complex.

Atopic Dermatitis in Domestic Animals: What Our Current Understanding Is and How This Applies to Clinical Practice

Atopic dermatitis is a clinical syndrome that affects both people and animals. Dogs closely mimic the complexity of the human skin disease, and much progress has been made in recent years in terms of our understanding of the role of skin impairment and the identification of new treatments. Cats and horses also develop atopic syndromes which include both cutaneous and respiratory signs, yet studies in these species are lagging. It is now recognized that atopic dermatitis is not a single disease but a multifaceted clinical syndrome with different pathways in various subgroups of patients. Appreciating this complexity is clinically relevant as we develop more targeted treatments which may work well in some patients but not in others. Different phenotypes of atopic dermatitis have been described in dogs, and it is possible that phenotypes related to breed and age may exist in other animals similar to how they are described in people. The awareness of different mechanisms of disease leads to the desire to correlate different phenotypes with specific biomarkers and responses to treatment. In this review, the current understanding and updated information on atopic syndrome in animals are described, highlighting opportunities for further studies in the future.

Treatment of the feline atopic syndrome - a systematic review

BACKGROUND

Feline allergic skin disease and asthma occur regularly in small animal practice.

OBJECTIVES

To provide evidence-based recommendations for small animal practitioners on the treatment of feline atopic syndrome (FAS).

METHODS AND MATERIALS

The authors reviewed the literature available before February 2020, prepared a detailed evidence-based literature review and made recommendations based on the evaluated evidence.

RESULTS

Sixty-six papers and abstracts were identified describing treatment interventions for FAS and evaluated to establish treatment recommendations. For many treatment options, the papers were retrospective, open studies or case reports.

CONCLUSION AND CLINICAL RELEVANCE

In this review, there was good evidence for the efficacy of systemic glucocorticoids and ciclosporin, and limited evidence for the efficacy of topical glucocorticoids, oclacitinib and allergen-specific immunotherapy in feline atopic skin syndrome. Evidence pointed to low-to-moderate efficacy for antihistamines, fatty acids and palmitoyl ethanolamide. In feline asthma, there was good evidence for the efficacy of oral and inhaled glucocorticoids, and limited evidence of moderate efficacy for allergen-specific immunotherapy. Evidence supported low-to-moderate efficacy of mesenchymal stem cells, inhaled lidocaine and oclacitinib as treatments for feline asthma. For almost all therapeutic options (with the exception of glucocorticoids and ciclosporin), more randomised controlled trials are needed.