Clinical efficacy of sublingual allergen-specific immunotherapy in 22 cats with atopic dermatitis

Open trial of recombinant Der f 2 pullulan-conjugated immunotherapy in cats

BACKGROUND

Allermmune HDM (Zenoaq) is a recombinant Dermatophagoides farinae 2 (Der f 2) pullulan-based immunotherapy vaccine whose efficacy on house dust mite allergic dogs has been demonstrated. There is no published information on its use in cats.

OBJECTIVES

The objective of the study was to evaluate the safety and short-term effects of Allermmune HDM in Dermatophagoides farinae (Df)-sensitised cats.

MATERIALS AND METHODS

Eleven cats diagnosed with atopic skin syndrome received Allermmune weekly for six weeks then monthly for three months (total duration 18 weeks). On Weeks 0, 6 and 18 clinical lesions were assessed by the Feline Dermatitis Extent and Severity Index (FEDESI); owners assessed pruritus with a 10-cm Visual Analog Scale (pVAS). Concurrent medication use was recorded. The allergen-specific immunoglobulin (Ig)E were measured before study inclusion with a commercial serological assay.

RESULTS

There were no evident adverse effects. FEDESI and pVAS improved significantly after six weeks (p = 0.001 and p = 0.01, respectively). The pretreatment Df-specific IgE levels were significantly higher in the cats with improved clinical scores than in the cats with no clinical score change (p = 0.009).

CONCLUSIONS AND CLINICAL RELEVANCE

Allermmune HDM may be safe in cats and has the potential to alleviate signs of atopic skin syndrome. Allergen-specific IgE levels may represent an efficacy marker. Controlled studies of longer duration and larger sample size are worth pursuing.

Nothrus mite as a potential cause of exacerbation of pruritus in a cat

Objectives

Morphological and molecular approaches were used to identify arthropods associated with feline pruritus. The literature associated with the arthropod genus identified was reviewed.

Methods

On two occasions (summer 2020 and summer 2021), the owner of a cat with seasonal pruritus (commenced 2020) found the cat's bed was substantially infested with arthropods suspected of being associated with exacerbated pruritus. The pruritus was largely itching and hair loss, particularly on the abdomen, and flaking skin patches. On the second occasion (2021), examples of the arthropods were sent to the parasitology laboratory at the Norwegian University of Life Sciences for identification. They were examined by stereomicroscopy and tentatively identified based on morphology. DNA was extracted, and identification confirmed by PCR and sequencing. The literature was reviewed to determine whether this arthropod genus has previously been considered to be associated with pruritus or the infestation of mammals.

Results

Based on morphological characteristics, the arthropods were tentatively identified as Nothrus species mites. This was confirmed by PCR. A literature review found no previous reports of pruritus or other clinical signs associated with Nothrus species mites, and mites were not found on the cat. However, this mite has previously been found on small mammals at densities exceeding that expected of incidental stragglers.

Conclusions and relevance

The large number of Nothrus species mites could have exacerbated the cat's pruritus. By publishing this study, we hope to alert veterinarians to the possibility that Nothrus species mites may cause or exacerbate pruritus in cats.

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.