Skin therapy 1 Flashcards
4 steps to managing allergic skin disease
- avoidance
- medication to control pruritus and erythema
- immunomodulation
- control of secondary flare-factors
* combination, tailored to individual*
How well can allergens be avoided
- fleas - possible?
- food - YES
- environmental - not really, house dust mites (dead can still be allergenic), epithelia of different species (only if exposure can be limited), pollens (seasonal)
What does shampoo therapy do?
- remove allergens from skin
- improve skin/coat hygiene and care
- efficacy rarely documented
- owner compliance important
Name 2 types of shampoo
- containing lipids, complex sugars, antiseptics (Allermyl, Virbac)
- oatmeal shampoo
Options - medical tx of pruritus
POWERFUL (80% efficacy):
- GCs
- Ciclosporin (Atopica)
- (Tacrolimus: Protopic ointment)
- Oclacitinib
OTHERS (30% efficacy):
- antihistamines
- EFAs
- (chinese herbal medicine)
- (not recommended: progestagens (cats, pentoxifyllin, misoprostol)
- combination of above
Adverse effects - GCs
- Immediate: PU/PD, polyphagia, restlessness
- Long-term: HAC, weight gain, CT
How useful for topical GCs?
limited use in animals, Cortavance
Outline oral GCs
- prednisolone (short-acting)
- anti-inflammatory dose (dog 0.5-1mg/kg/d, cat 1-2mg/kg/d)
- aim for long term control: lowest necessary dose given on alternate days - minimises adrenal suppression)
How should you monitor a patient on GCs?
every 6 months perform haem and biochem and urine culture
How does ciclosporin work?
- cacineurin-inhibitor
- targets TC response more than GCs although efficacy is comparabe
- slow onset of effect (4 weeks) - not for acute itch
Adverse effects - ciclosporin
- transient V+D
- gingival hyperplasia
- hirsutism (increased hair growth)
- lameness
- EXPENSIVE
Describe antihistamines
- little EBVM, up to 30%?
- try different types (each for 10-14d)
- chlorpheniramine (only one for cats), clemastine, hydroxyzine
- NL for animals at all
What essential fatty acids are used for medical management of pruritus?
- N3 (fish oils) and N6 (plant oils) (eicosanoids)
- interact with arachidonic acid cascade
- more effective for seasonal disease?
- steroid sparing
What is oclacitinib (Apoquel)?
- new product for medical management of pruritus
- inhibits JK-1 –> switches off itch but not reddness
- authorised in dogs >12 years
- adverse effects after 14 days
Define ASIT
Allergen-specific immunotherapy
Describe ASIT
- injection of allergen extract SC at increasing quantities and intervals to patients with AD
- PEOPLE: decreases inflammatory cells, Ig, modulation of TH1/TH2 response
- PREPARATION: aqueous, alum precipitated or glycerinated
Efficacy - ASIT for AD
- full efficacy may take up to 9 months
- up to 50% (DOGS), higher in horses, unknown in cats
How can individual allergens be identified for ASIT?
- INTRADERMAL TEST: mast cell bound IgE, requires GA
- IgE serology: allergen-specific IgE (most commonly)
Define SLIT
= sublingual immunotherapy
- alternative to ASIT
- drops are sprayed under tongue so no injection
PROS - ASIT and SLIT
- safe
- potential AEs (anaphylaxis) rare, no long term SEs
- infrequent tx (monthly)
- often more cost effective (esp large breeds)
- preventative not reactive
CONS - ASIT and SLIT
- initial higher cost
- risk of anaphylaxis
- full efficacy may take several months
- compliance may drop with long term approach
- flare-factors need controlling during initial tx to allow full assessment of efficacy
- syringes dispensed to owner
What are the most common flare-factors in AD?
- fleas
- other concurrent allergens (food, environmental)
- Staph pyoderma
- Malassezia dermatitis
What should you say to owner in managing allergic skin disease?
- life-long implications
- no complete cure, overall management
- waxing and waning course of disease
What neoplasia can be mistaken for allergic skin disease?
EPITHELIOTROPIC LYMPHOMA
Describe epitheliotropic lymphoma
- Ddx allergic skin disease
- affects epidermis
- usually dogs 10+ years (allergy younger)
- exfoliative eryhtroderma (whole skin is red)
- digital pad involvement (unlike allergic skin disease where interdigital skin is affected)
- thus some aspects don’t fit exactly with typical hx of allergic skin disease so this should prompt consideration of this condition
