Atopic Dermatitis & Dermatophytoses Flashcards
What is the definition of atopic dermatitis?
A genetically-inherited, relapsing, pruritic dermatitis most commonly associated with IgE environmental allergens
What 3 things do animals with atopic dermatitis have?
Type I hypersensitivity (IgE)
T cell imbalances
Primary skin barrier defect
What are the differences in T cell imbalances between chronic and acute disease?
Acute- too much T helper 2
Chronic - too much T helper 1
What stain and technique help you visualize lipid-based material?
EM
Ruthenium Tetroxide
What are the main routes of allergen access in atopic dermatitis?
Inhalation
Percutaneous absorption
What breeds are predisposed to atopic dermatitis?
Terriers Shar-pei Setters Retrievers Beagles Dalmatians Cockers
What are the clinical signs of atopic dermatitis?
Onset 1-3 years old
Seasonal at first, progressive worsening with time
Pruritus and erythema
With chronicity- excoriations, lichenification, hyperpigmentation
Secondary infections
How do you diagnose atopic dermatitis?
Exclusion of other pruritic diseases
Willemse’s criteria (at least 3 major and 3 minor criteria)
What are the major and minor Willemse’s criteria?
Major: Pruritus Facial/digital involvement Lichenification of flexor surface Chronically relapsing Familial history Breed predilection
Minor: Onset of clinical signs before 3 years old facial erythema Bacterial conjunctivitis Superficial pyoderma Hyperhydrosis Positive skin test Elevated allergen specific IgE
What are the two types of allergy testing?
Intradermal Skin Test (IDST)- evaluates IgE in skin
Serology- evaluates IgE in blood
What is hyposensitization therapy?
Allergy shots
Based on past positive reactions
No more than 12 allergens/vaccine
What does anaphylaxis look like in the dog?
Vomiting, diarrhea, weakness within 1-2 hours post-exposure
When is systemic glucocorticoid therapy indicated?
Short season use
No concurrent pyoderma
No concurrent demodicosis
What is cyclosporine?
An immunomodulant (suppresses T cells and cytokine production) used as a lifelong therapy
What is oclacitinib?
Apoquel
Recently released drug that targets pruritus of various causes (Janus Kinase (JAK) inhibitor)
Extremely effective and fast acting
What is IL-31 monoclonal antibody?
Injectable 1x/month
Blocks IL-31 which is important in the transmission or pruritus
Used in combination with other therapies
Why are essential fatty acids used in therapy for atopic dermatitis?
Are anti-inflammatory
Contribute to barrier function and restoration of normal lipid composition
What is capsaicin used for?
Active ingredient in chili pepper
Used for localized dermatitis (e.g. Lick granuloma)
Initial worsening followed by prolonged relief
What is tacrolimus?
Topical calcineurin inhibitor, mechanism similar to cyclosporine
Minimally absorbed so extremely safe
Initial burning sensation followed by improvement after 1-2 weeks
What is phytosphingosine used for?
Restore barrier function
What are the most common dermatophytes for cats and dogs and what are their reservoirs?
M. Canis (cats)
M. Gyseum (soil)
T. Mentagrophytes (rodents, rabbits, pocket pets)
Predisposing factors for dermatophytoses?
Lack,decreased grooming *Presence of microtrauma* Excessive hydration,maceration Warm temperatures and humidity Lack of sun exposure Strong cell-mediated immunity
What types of animals are pre-disposed to dermatophytoses?
White persians and himalayan cats
Terriers
Immunosuppressed animals
What is a common clinical sign for all dermatophytoses?
Pruritus
