Pharmacology of drugs used in autoimmune dermatopathies in cats and dogs: A narrative review

Immunosuppressive drugs are the mainstay of treatment for many feline and canine autoimmune skin diseases, either as monotherapy or in combination with other drugs. Treatment with these drugs is often lifelong and may have long-term consequences on the affected animal's overall quality-of-life. Clinicians need to understand the pharmacology of immunosuppressants in planning and executing the treatment regimen for the best possible clinical outcome, as well as reducing the risk of adverse effects. This review paper will focus on the mechanism of action, pharmacokinetics and pharmacodynamics, clinical uses and adverse effects of immunosuppressive drugs used to treat autoimmune dermatoses in cats and dogs. These include glucocorticoids, ciclosporin A, azathioprine, chlorambucil, mycophenolate mofetil, oclacitinib and Bruton's tyrosine kinase inhibitors.

The Need of Differential Diagnosis Between Vulvar Lichen Sclerosus and Autoimmune Dermatoses in Adolescent Girls

INTRODUCTION

Vulvar lichen sclerosus (VLS) is a chronic inflammatory condition affecting the anogenital region, which can manifest in prepubertal or adolescent patients. The prevailing theories point to autoimmune and genetic factors. The primary symptoms of VLS typically include vulvar itching, discomfort, dysuria, and constipation. Physical examination often reveals a characteristic figure 8 pattern, involving the labia minora, clitoral hood, and perianal region. However, these symptoms and the age of onset are nonspecific and require differentiation from autoimmune dermatoses such as bullous diseases, pemphigus diseases, epidermolysis bullosa acquisita, and dermatitis herpetiformis. We performed this study to distinguish VLS from autoimmune dermatoses, and in doing so, uncover the underlying causes of chronic vulvar changes. This knowledge will enable healthcare providers to offer appropriate medical care to affected patients.

METHODS

The study was conducted between July 2020 and February 2021, with a sample of 55 girls aged 2-18 years who did not have any systemic diseases. The study group was composed of 20 girls previously diagnosed with vulvar lichen sclerosus, while the control group included 35 girls without VLS. Questionnaires regarding the medical history of the children were completed by their legal guardians. Blood samples were collected and analyzed biochemically to assess human immunoglobulin A (IgA), IgG, and IgM antibodies against various substrates, including the desmosome of stratum spinosum, basement membrane zone, desmoglein 1 (DSG1), desmoglein 3 (DSG3), BP180-NC16A-4X, BP230gC, pemphigoid antigen, collagen type VII NC1, transitional epithelium, gliadin (GAF-3X), endomysium (EMA), and cellular nucleus (ANA).

RESULTS

The analysis of the study group revealed that the most commonly observed signs and symptoms included: itching, soreness, burning sensations, and excoriation, as well as erythema or/and pallor of the skin and perineal mucosa. Among the assessed antibodies, only anti-GAF3x antibodies and ANA antibodies were detected. However, the results did not reach statistical significance (p > 0.5).

[Immunoadsorption in dermatology]

Autoimmmune bullous diseases are mediated by pathogenetically relevant autoantibodies against components of the epidermis and/or superficial mucous membranes (in pemphigus) and structural proteins of the dermal-epidermal junction (in pemphigoid diseases). Using immunoadsorption (IA), an already well-established procedure in cardiac and rheumatic disorders, antibodies can be removed from the plasma. At present, most data on the adjuvant use of IA in dermatology are derived from patients with severe and/or refractory pemphigus vulgaris or pemphigus foliaceus and also from patients with pemphigoid diseases. Additionally, in the last few years different protocols for IA in patients with severe atopic dermatitis and elevated total serum IgE levels have been published. While panimmunoglobulin adsorbers are mainly used in dermatology, an IgE-specific adsorber has been used in some patients with atopic dermatitis and in the future, antigen-specific adsorbers are to be expected that will enable the specific reduction of autoantibodies.