Skin Therapy - Allergy Flashcards
4 main ways to manage allergic skin disease?
- avoidance
- medication: pruritis and erythema
- immunomodulation
- control of 2* flare factors
Which type of allergy is easiest to avoid?
food
- fleas potentially
- house dust mites very difficult to avoid (hard to eradicate and dead mites still allergenic)
Is shampoo therapy advocated?
- may remove allergens from skin
- allermyl (lipids, sugars, antiseptic)
+ others (oatmeal episoothe) - but not just SHAMPOO
- rare evidence but not doing harm, may be halpful
- monitor
What are the main 3 most efficacious options for medical tx of pruritis?
- Glucocorticoids
- Ciclosporin [atopica has flavouring, cyclavance and sporimmune more recent] (+ topical ciclosporin Tacrolimus [protopic])
- Oclacitanab [Apoquel] (lic but not available atm)
What additional therapies may be used at medical tx of pruritis?
> antihistamines - better for seasonal use - preventative (stops MC degranulation, not useful if already degranulated) - 30% effecivity - weeks to build up to theraputic doses > EFAs - do no harm > chinese herbal medicine, progestagens (cats) side eeffects, pentoxyfylline and misoprostol not very good, but people will know about them/use them)
Advantages of GC use? Most common drug and dose rate?
- effective, readily available, cheap
- prednisolone (Short acting)
- anti-inflammaotry dose dog 0.5-1mg/kg/d cat 1-2mg/kg/day (aim long term control LOWEST POSSIBLE DOSE alternate days to prevent adrenal suppression)
Adverse effects of GCs? Alternative form?
- immediate: PUPD, polyphagia, restlessness
- long-term: hyperadrenocorticism, ^weight, connective tissue problems
> topical GCs for localised lesions eg. Fusiderm (+fusidic acid ABx) Cortavance (hydrocortisone)
What is ciclopsorin? Efficacy? Side effects?
- Cacineurin-inhibitor
- more targetting T-cell suppression than GCs
- efficacy = GCs (~80%)
- freq side effects = GCs (prednisolone)
> VD+, gingival hyperplasia, hirsuitism, lameness
> hepato- or nephrotoxicity not at therapeutic doses
> ^ risk neoplasia? V immune surveillance
> expensive
> slow onset of action
How regularly should chronic cases on long term steroids be checked up?
monitor q6months
- haem/biochem
- urine
How long ciclosporin onset of action?
4 weeks dog or 7 weeks for cat
not for acute itch
Mechanism of action of Apoquel? Licensed?
(Oclacitinib) Janus-kinase 1 inhibitor (IL31 cytokines) pruritis but NOT inflam
- lic dogs > 12 months (tx pruritis ssociated with allergic dermatitis and atopic dermatitis) currently unavailable
Adverse effects of Oclacitinib?
- doesnt tx inflammation so 2* bacterial pyoderma still common
- monitor
- VD+/anorexia/lumps/lethargy been reported
Egs antihistmaines?
- chlorpheniramine (only one for cats)
- clemastine
- hydroxyzine
> try different types fro 2 weeks each
Which antihistamines are licensed for animal use? Are tehy advocated?
NONE!!!
- human piriton get from pharmacy
- may be effective
- steroid sparing
What types of EFA are usually used?
fish oils N3 and plant oils N6
- arachidonic acid cascade
When are EFA advocated? When should they not be used?
- steroid sparing
- safe
> do not use during food trials (gelatin)
> take few weeks to kick in so long term
What types of EFA are available?
- vet (start with these)
- shop bought
Options for cheap tx plan for atopic dermatitis?
- GCs
- EFAs
- antihistamines?
- shampoos
> compliance necessary for success!
How often should GCs dose be reduced?
~ 3 months
What is ASIT? Effects? Efficacy?
- injections of allergen extract (SC) at increasing quantities
- in humans v inflammaotry cells, Ig, modulation of Th1/Th2 response [missing out Langerhans cells alleviates some of immune response?]
- aqueous, alum precipitated or glycerinated available
- injected at ^ doses, ^ intervals ~ 9 months (ending with ~1ml/month, owners can do at home)
- dogs 50% horses higher
Cost of ASIT?
- £300 per allergy testing
- vax ~ £200
How is ID of individual allergens?
- intradermal test for mast cell bound IgE
- IgE serology for FcERIa (more common 1st opinion)
What main allergens are tested for?
- house dust mites
- epithelia
- pollens
- NOT FOODS (IgG and IgE to food are physiological not allergic)
How should allergy tests be used?
Combine with clinical signs (eg. time of year etc.)
Long term plan using ASIT?
- 9 months
- review: if working, continue for life; if hasnt helped then stop
What alternative ROA for immunotherapy is now available?
Sublingual (SLIT)
Pros and cons of ASIT and SLIT?
> pros - safety - injection monthly only - may be cost effective - preventative not reactive - good for large dogs > cons - anaphylaxis (1st time escpecially) rare - initial cost - full efficacy ~ months - compliance may be poor - flare factors need control during initial tx to assess efficacy - syringes dispensed to owner
Most commonly recognised flare factors?
- flea/parasites
- concurrent allergens (fleas, food, environment)
- staphylocollal pyoderma
- malasezzia dermatitis
What must owners be made aware of with allergic skin disease?
- waxing and waning disease
- life long
- follow up [ruritis levels and adverse effects of therapy
What neoplasia may mimic atopic/allergic skin disease? How would you differentiate?
- Epitheliotropic lymphoma > depigmentation of nasal planum > exfoliative erythroderma (all skin not just predilection sites) > old age of onset > foot pads involved (not interdigital) > plaques and nodules > dx: histo, poor prog -> chemo
