Atopic Dermatitis - Treatment Flashcards
What are considerations for treatment of atopic dermatitis?
- Acute therapy = Initially and for flares
- Maintenance therapy = Chronic and to prevent flares
- Cost = Expensive / chronic disease
- Other considerations = e.g. owner unable to bath dog
- Simple therapy = Better owner compliance, Reduced owner stress
- Complex therapy = Increased owner and animal stress / QOL, Time consuming
- Inadequate therapy = Frequent flares, More chance of AMR
- Over therapy = Increased risk of adverse events and chronic side- effects
How are therapies chosen?
Based on =
* Good evidence (i.e., evidence based medicine)
* Underlying pathogenesis
* Nature of the disease
* Pruritus
* Inflammation
* Tendency to secondary infection
What is disease pathogenesis of CAD?
- Genetic predisposition =
- skin barrier dysfunction
- immune dysregulation – skin inflammation
- Environmental factors =
- specific allergen sensitisation
- enhanced microbial colonisation
What does CAD treatment consist of?
- Improve the skin barrier
- Allergen avoidance and ASIT
- Control inflammation and pruritus
- Control flare factors (e.g. microbial overgrowth)
What are aims for improving skin barrier function? + What can be used?
- Reduce transepidermal water loss
- Reduce exposure to environmental allergens and irritants
- Reduce microbial colonisation and cutaneous inflammation
Use =
* Non irritating shampoos
* Topical moisturisers and emollients
* Supplementation with oral EFAs
* Application of topical EFA- containing formulations
What are aims of allergen avoidance + allergen 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
What is the most important source of allergens?
- House dust + Storage mites
- less important = tree, grass + weed pollens
What is allergen immunotherapy? How can it be given?
- 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
- Injections =
- Aqueous – allergens in water
- Adjuvanted – allergens bound to aluminium salts
- Allergoid – modified allergens designed to reduce IgE binding
- All injected subcutaneously in increasing doses – many different protocols
- Oral =
- Aqueous – with glycerol - Under the tongue twice daily
- Intra-lymphatic - Injected into popliteal lymph node monthly
What are aims of anti-inflammatory + anti-pruritic therapies?
- 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 overdosage or overuse
What are examples of anti-inflammatory + anti-pruritic therapies?
- Glucocorticoids =
-Systemic (prednisolone, methyl prednisolone, dexamethasone)
-Topical (betamethasone, hydrocortisone aceponate) - Calcineurin inhibitors =
-Systemic (ciclosporin)
-Topical (tacrolimus ointment) - Janus Kinase inhibitor
- Oclacitinib
- Biologics - Lokivetmab
- Antihistamines
What are adverse effects of systemic glucocorticoids?
- Polyphagia
- PU/PD
- panting
- behaviour changes
- iatrogenic hyperadrenocorticism
- increased risk of UTI
What are adverse effects of oral calcineurin inhibitors?
- GI signs
- Gingival hyperplasia
- Viral papillomas
- Hirsuitism (excessive hair growth)
What can use of Janus kinase inhibitor cause? (oclacitinib)
- May increase susceptibility to infection, including demodicosis & exacerbate neoplastic conditions
What are contraindications of using oclacitinib?
- <12 months old or <3 kg BW
- Breeding dogs or dogs with serious infections, underlying neoplasia or immune-suppression
What does lokivetmab do?
- Targets IL-31 = pruritogenic cytokine (narrow action)
