sash : atopic dermatitis treatment by dr linda vogelnest
TRANSCRIPT
Atopic Dermatitis Linda Vogelnest BVSc MACVSc FACVSc
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Atopic Dermatitis
“Changing” disease…. New Definition:International Task Force (2002) canine atopic
dermatitis
- “Genetically-predisposed - Inflammatory & pruritic allergic skin
disease - Characteristic clinical features - Associated most commonly with IgE
antibodies to environmental allergens”
OLIVRY, DE BOER, GRIFFIN, HALLIWELL et al (2001). Veterinary Immunology and Immunopathology 81: 143-146
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Atopic Dermatitis
Genetic Influence:1. Immunological dysfunction
– T-lymphocyte driven– Mast cells, IgE
• 2 subsets:– High allergen-specific IgE producers– Low allergen-specific IgE producers
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Atopic Dermatitis
Genetic Influence:1. Immunological dysfunction
– T-lymphocyte driven2. Skin barrier dysfunction
– Lipid changes:• more heterogeneous, thinner, shorter
lamellae• ↓ ceramides (non lesional & lesional
skin) – Protein changes:
↓ filaggrin expression (beagles)
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Microbes, allergens
Water
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Atopic Dermatitis
Genetic Influence1. Immunological dysfunction
– T-lymphocyte driven2. Skin barrier dysfunction
– Lipid changes– Protein changes
Environmental Influence– Allergen exposure– Microbe exposure (“hygiene
hypothesis”)
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Microbes, allergensWater
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Atopic Dermatitis
• Atopy = broad allergic group
• Humans– allergic rhinitis
– allergic asthma
– atopic dermatitis (eczema, AD)
• Dogs/Cats – AD most common
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AD: Treatment
Multi-faceted approach1.Acute flare plan2.Long-term management plan
Options:1.Minimise allergen &/or irritant exposure2.Immunotherapy3.Symptomatic therapy
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OLIVRY, DE BOER (2010). Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. Veterinary Dermatology 21: 3; 233-248.
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AD: Treatment
1. Minimise allergen exposure– requires skin test (or allergen-specific IgE serum test) →
id allergens– most useful dust mites, mould spores
• see human literature
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AD: Treatment
1. Minimise irritant exposure– variety of factors
• grass• certain fabrics: wool• heat• dryness• shampoos (rarely)
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AD: Treatment
1. Minimise allergen/irritant exposure2. Immunotherapy
– requires skin test (or allergen-specific IgE serum test) → id allergens
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AD: Immunotherapy (allergen-specific)
• Potentially changes allergic response– T-helper subset change (II to I)– 60-70% improve (20-30% excellent)
• Recommended when – allergy severe– allergen avoidance not possible/not effective– symptomatic tx ineffective or → side effects– preferred to avoid medications
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AD: Immunotherapy (allergen-specific)
• Requires owner commitment– Ideally minimum 2-yr program– 6-12 months to see benefit in many– Average cost $10-15/wk (~$300 per 7mnths supply)
• Side effects - very rare– itch (→ change dose)– Urticaria; Anaphylaxis - extremely rare
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AD: Treatment
1. Minimise allergen exposure2. Immunotherapy3. Symptomatic tx
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AD: Treatment
1. Minimise allergen exposure2. Immunotherapy3. Symptomatic treatment
1. Acute flare plan2. Long-term management plan
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OLIVRY, FOSTER et al (2010). Interventions for atopic dermatitis in dogs: a systematic review of randomized controlled trials. Veterinary Dermatology 21: 1; 4-22.
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AD: Treatment
1. Minimise allergen exposure2. Immunotherapy3. Symptomatic treatment
1. Acute flare plan• Treat active infections – when present!• Soothing• Anti-inflammatory• Limit self-trauma
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AD: Treatment
1. Minimise allergen exposure2. Immunotherapy3. Symptomatic treatment
1. Acute flare plan2. Long-term management plan
1. Infection prevention – when relevant!2. Anti-inflammatory3. Skin barrier repair
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AD: Symptomatic Tx
A. Safest Options• Antihistamines• Fatty acids• Shampoos• Moisturisers/topical soothing products• Limit self-trauma
NB Rarely spectacular response with severe acute flares; most effective as part of long-term plan
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AD: Symptomatic Tx
Antihistamines– Block histamine effects (not IgE, Langerhan’s cells, T cells, cytokines
etc etc)– Safe– Variably effective (rarely spectacular) – Trial a number– Little pharmacokinetics (dogs or cats): dose rates?– Higher success cats, help some dogs
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AD: Symptomatic Tx
Fatty acids– pruritus? - altered eicosanoid
production– improve barrier function (stratum
corneum)• Omega-3
– fish oil (pump bottle, capsules); flax seed oil• Omega-6
– Evening primrose oil (50-100mg/kg sid)– Cold-pressed sunflower/safflower oils (2mls/kg
sid) – borage oil, blackcurrant oil
• Combinations e.g. Megaderm®– energy intake ( other dietary intake)– care with pancreatitis?
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AD: Symptomatic Tx
Shampoo Therapy– Regular appropriate shampoo therapy
helps vast majority atopic dogs (& can help cats)
• wkly → twice wkly• skin drying rarely problem• NOT too vigorous rubbing of coat against
lay of hair• 10-minute contact time for medicated
shampoo (use timer)• rinse well
– Avoid drying shampoos in most cases: tar-based, selenium, benzoyl peroxide
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AD: Symptomatic Tx
Shampoo Therapy– Antibacterial/antifungal shampoos– Soothing– Barrier Repair
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AD: Symptomatic Tx
Shampoo Therapy– Antibacterial/antifungal shampoos
FOR recurrent pyoderma/malassezia dermatitis•Mediderm (piroctone olamine)•Pyoben-S or Pyohex (chlorhexidine)•Malaseb (chlorhex/miconazole)
– Soothing– Barrier Repair
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AD: Symptomatic Tx
Shampoo Therapy– Antibacterial/antifungal shampoos
– Soothing• Episoothe (oatmeal); Allergroom (emollient)• Aloveen (aloe vera/oatmeal)• PAW sensitive skin (no sulphates)
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AD: Symptomatic Tx
Shampoo Therapy– Antibacterial/antifungal shampoos– Soothing– Barrier Repair
• Nutriderm shampoo/conditioner
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AD: Symptomatic Tx
Moisturisers– mainstay of symptomatic tx for AD in people– rarely as effective in dogs, cats; important with dry
scaly skin– Humectants
• attract water e.g. lactic acid, urea - non-oily• prevent water loss e.g. propylene glycol, glycerine,
sorbolene– Emollients
• fill spaces between kc’s with oil e.g. Allergroom, Alpha Keri bath oil, other oils (almond, corn, safflower, sesame), animal fats (lanolin), hydrocarbons (mineral oil, paraffin oil, petrolatum)
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AD: Symptomatic Tx
Limit self trauma• E-collar• Body-suits• Bandages
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AD: Symptomatic Tx
A. Safest Options• Antihistamines• Fatty acids• Shampoos• Moisturisers/Topical soothing products• Limit self-trauma
B. Stronger Anti-inflammatories• Topical GCs• Systemic GC• Cyclosporine• Other
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AD: Symptomatic Tx
Topical Glucocorticoids– mainstay of symptomatic tx for AD in
people– may help minimally haired localised
areas– more potent most effective: daily for short
periods; 1-2X wkly longer-term; may thin skin and risk infections
• Aristocort cream/oint (triamcinalone)• Elocon lotion/cream/oint (mometasone)• Panalog oint (triamcinalone/neomycin)• Fuciderm gel (betamethasone/fusidic
acid)• Cortavance spray (hydrocortisone
aceponate)
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AD: Symptomatic Tx
Topical Glucocorticoids– Less potent options with more transient effect
• Cort-Hex , Neocort (hydrocortisone) creams, lotions, ointments
– Absorption best from moist skin– Limit licking 10-mins after application
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AD: Symptomatic Tx
Systemic Glucocorticoids– most effective, cheap, fast-acting option for severe
allergy flares (all) in many patients
– short-acting forms reasonably safe intermittently at low doses if other options not effective
• severe steroid side-effects with even low-dose short-term
• high risk for side effects with long-term
• cats more resistant some steroid side effects cf. dogs – still can be severe
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AD: Symptomatic Tx
Systemic Glucocorticoids– Measures to risk side effects:
• Use short-acting only – often oral prednisolone– for severe flares injectable formulations (e.g.
dexamethasone) more potent• Restrict to low doses for longer-term use
– pred 0.1-0.2 (dogs) or 0.2-0.4 (cats) mg/kg eod or less• Low regular dosing (pred 0.5mg 2X wkly) to hold
continual allergies at more comfortable level better than repeated tapering courses
• Avoid long-acting preps (DepoMedrol)– Recommend safer alternatives, steroid-sparing
role
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AD: Symptomatic Tx
Cyclosporine– Severe, poorly-responsive AD MUCH easier
• dogs + cats (off-label; oral solution in USA)• including cases with recurrent 2º infections
– Potent immunosuppressive (more specific T-cells) – No general body metabolic side effects– Expensive!!– Slower onset effect (2-5wks for good control) – Doesn’t work for flea allergy, contact allergy
• ENSURE AD FIRST!
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AD: Symptomatic Tx
Cyclosporine– Start 5mg/kg sid most; 7mg/kg cats, dogs <5kg
• Dose with food initially– Continue until good control (by 6wks), then gradually taper in 2wk steps
• dosing interval or daily dose• typical maintenance dose 1-3mg/kg sid
– dose & cost by:• concurrent ketoconazole 5mg/kg bid or can combine to sid
– GIT signs (inappetance, vomiting) some patients• concurrent grapefruit juice ? ~ 3-4 ice cubes/dog• dose on empty stomach (after to lower doses)
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AD: Symptomatic Tx
Cyclosporine - Side effects (few):– Diarrhoea most frequent, rarely severe; Vomiting (if no food)
• both more likely at higher doses– Gingival hyperplasia, papillomatosis, hirsuitism - higher doses
– Unusual infections: fungal osteomyelitis; papillomas
– Fatal toxoplasmosis reported in cats• FIV/FeLV first• warn owners to act promptly if cat unwell (pyrexia?)• no clear evidence prophylactic Ab’s (clindamycin, TMS) risk• very rare, but increased risk cf. dogs
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AD: Treatment
1. Minimise allergen/irritant exposure2. Immunotherapy3. Symptomatic tx
1. Acute Flare Plan2. Longer-term Management Plan
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