46. Atopy Flashcards
Canine atopic dermatitis?
Genetically inherited predisposition to anaphylactic or allergic
diseases
CANINE ATOPIC DERMATITIS (CAD)
Common skin disorder; Hereditary disposition to develop pruritic
inflammatory skin disease associated with IgE antibodies (which
typically target environmental allergens)
Predisposed: Dogs > Cats; 6 months – 3 years
West Highland White Terrier; Labrador; German Shepherd and many
more…
Feline atopy?
FELINE ATOPY
Clinical signs
§ Generalised pruritis § Facial pruritis
§ Miliary dermatitis-like lesions § Pruritic ears
§ Symmetric alopecia § Indolent ulcer
Pathogenesis and allergens?
PATHOGENESIS
- Percutaneous sensitisation to environmental allergens
and/or allergens from food
- Induced skin infiltration by various inflammatory cells
- Activation of resident cells
- Local production of inflammatory/itch mediators
ALLERGENS
Ectoparasites: Fleas
Environmental factors:
§ Mites § Fungi
§ Dander § Mould
§ Pollen § Feathers
Cutaneous bacterial colonisation or infection
Epidermal barrier dysfunction
Forms and clinical signs?
FORMS:
§ Atopic dermatitis (most common)
§ Atopic rhinitis
§ Atopic conjunctivitis
CLINICAL SIGNS
§ Pruritis § Erythema
§ Secondary skin lesion § Pyoderma
§ Seborrhoea § Papules
§ Lichenification
Diagnosis?
DIAGNOSIS
It is important to exclude other differential diagnoses
If you suspect canine atopic dermatitis, you should establish:
§ The age of onset
§ Seasonality of clinical signs
§ Pruritis with no skin changes at onset
§ Family/breed disposition
§ Previous response to glucocorticoids
Allergy testing
Not to be used for diagnosing CAD
§ Intradermal skin testing
§ IgE testing
Criteria for atopy?
CRITERIA FOR ATOPY
Favrot’s criteria (2010)
These criteria have a sensitivity & specificity of 80% when 5 out of 8
are fulfilled. Therefore this should be performed concurrently with
the previously mentioned and other diagnostics to avoid
misdiagnosis.
Onset of signs < 3 years of age
Dog living mostly indoors
Glucocorticoid-responsive pruritis
Pruritis sine materia at onset (Ø associated causal dermatosis)
Affected front feet
Affected ear pinnae
Non-affected ear margins
Non-affected dorsolumbar area
Treatment?
TREATMENT
CAD Requires a multimodal treatment approach to ↓ pruritis & inflammation
§ First identify & address the associated flare factors:
§ Fleabite hypersensitivity § Fleas
§ Bacterial overgrowth § Yeast overgrowth
§ Environmental allergens § Food allergens
§ Topical and/or systemic treatment ↓ pruritis &
Inflammation
Symptomatic
§ Glucocorticoids: Prednisolone (long term)
§ Cyclosporine
§ Apoquel (oclacitinib)
Topical: Shampoo; Spray; Spot-on; Cream; Gel
Other
§ Antihistamine
§ Vitamins
§ Essential FAs
§ Non-specific immunotherapy
§ Desensitisation – Allergy vaccines (mitigation rather than
treating)