Treatment of Canine Atopic Dermatitis (CAD) Flashcards
What does the owners need to understand once CAD has been diagnosed?
- There is a need for further work to develop the correct protocol for their dog
- There will be flares
- We want to minimise the potential side-effects of therapy
How does the disease pathogenesis influence the therapy used?
Complex, multifactorial pathogenesis
Genetic predisposition
- Skin barrier dysfunction
- Immune dysregulation – skin inflammation
Environmental factors
- Specific allergen sensitisation
- Enhanced microbial colonisation
Treatment of CAD has which 4 aims?
- Improve the skin barrier
- Allergen avoidance and ASIT
- Control inflammation and pruritus
- Control flare factors (e.g. microbial overgrowth)
What are the 3 aims of improving skin barrier function?
- Reduce transepidermal water loss
- Reduce exposure to environmental allergens and irritants
- Reduce microbial colonisation and cutaneous inflammation
How can you improve the skin barrier?
Non irritating shampoos
Topical moisturisers and emollients
Supplementation with oral EFAs
Application of topical EFA - containing formulations
What are the aims of allergen avoidance and immunotherapy?
- Only preventative therapy
- Prevent/reduce worsening of clinical signs from further exposure to allergens
- ‘Desensitisation’ to environmental allergens via induction of tolerant state in peripheral T cells (full mechanism unknown)
What are the most important allergens involved in CAD?
House dust
Storage mites
What is allergen immunotherapy?
- Administration of gradually increasing quantities of an allergen extract to an allergic subject to ameliorate the symptoms associated with subsequent exposure to the causative agent
- Allergen intradermal testing (IDT) and/or IgE serology to identify specific hypersensitivities to environmental allergens
- First confirm CAD diagnosis
How long does allergen immunotherapy last?
Slow onset
4-6 months
Trial for a minimum of 12 months
What are the aims of controlling inflammation and pruritis?
- Long term reduction of inflammation
- Avoid ‘peak and trough’ cycles of inflammation
- Restoration of normal skin environment and prevention of microbial overgrowth
- Avoid side effects through over dosage or overuse
Name some anti-inflammatory and anti-pruritic therapies
Glucocorticoids - systemic and topical
Calcineurin inhibitors
Janus Kinase inhibitor
Oclacitinib [Apoquel®}
Antihistamines
List some adverse effects of systemic glucocorticoids
Polyphagia, PU/PD, panting, behaviour changes, iatrogenic hyperadrenocorticism, increased risk of UTI
Describe the use of topical glucocorticoids
Hydrocortisone aceponate 0.0584% (Cortavance®)
Topical diester glucocorticoid
Rapidly absorbed
Potent anti-inflammatory effects
Metabolised within the dermis
Minimal side effects
What is the main issue with topical steroid use?
Major safety risk is skin thinning with prolonged use (abdomen)
Intermittent application appears to prevent this and might delay flare recurrence of if
Describe the use of oral calcineurin inhibitors
Ciclosporin (Atopica®,Cyclavance®)
Inhibit T lymphocyte function via blocking calcineurin
