Flashcards in Equine Derm Deck (54):
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Potential infectious skin diseases of horses?
- ectparasites
- dermatophilosis
- folliculitis
- fungal (dermatopyhtosis)
- viral (aural plaques)
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Non-infectious equine skin diseases?
- allergies
- immune mediated
- endocrinopathy
- misc
- neoplasia
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Which ectoparasites affect horses? Esp common?
- chorioptes mite esp common (limbs and tail)
- psoroptes mite bit common (head and ears)
- neotrombicula autumnalis, Dermanyssus gallinae (seasonal)
- rarely: scabies, demodecosis
- ticks, lice, fleas, flies
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Where is chorioptes often seen?
- feathered hgorses
- pastern dermatitis
- peaks in winter
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Clinical signs chorioptes?
- pruritis, erythema, crusts, papules
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Tx chorioptic mange?
- fipronbil spray (repeat monthly, lots needed)
- avermectins (efficacy controversial)
- permethrins/pyrethroids (flumethrin acaricidaL)
> clip feathers
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Clinical signs of lice infestation?
- pruritis variable
- identify parasites!! people overlook
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Tx lice infestation
- fipronil spray
- syth pyrethroids
- systemic ivermectin (H. Asini sucking lice)
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are lice contagious?
Yes but species specific so only horses need treating
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How may flies cause problems in horses?
- bites and stings
- infected woudns
- hypersensitivity (esp culicoides sweet itch)
- laral myasis
- disease transmission (habronemiasis and onchocerchiasis)
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What worms cause itchy bottoms?
- pinworms
- oxyuris equi
> adults migrate from LI out of anus to lay eggs
- self trauma
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Most common skin allergy in horses?
Sweet itch
- insect bite hypersensitivity
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Where is sweet itch seen? WHen?
USually dorsal but ventral fly also exists
- always seasonal! Not winter
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Clinical signs of sweet itch??
- papules, crusts, skin thickening, alopecia
- seasonal pruritis
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What aged hroses sweet itch affect?
- > 6 months
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Ddx sweet itch?
- oxyuris equi
- insects
- other allergies
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Is intradermal testing for sweet itch indicated?
- shows exposure not hypersensitivity
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Does ASIT work for sweet itch?
No!!
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Tx sweet itch?
- anti-inflammatories/antipruritic (antihistamines, GCs)
- management
> flies live in areas of wet fields and low winds and cannot fly far
> move horses!
> rungs/hoods/fly spray
> stable between 4pm and 8am
> long term insecticides and repellants (synth pyrethroids [cypermethrin, flumethrin, deltamethrin, CARE FLISH!]
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Most common bacterial disease on the horse? How are these diagnosed? `
- Dermatophylsis congolensis (actinomyces) mud fever, affects cattle too if rain heavy > cytology on whole crust mixed with saline: "railroad tracks" may branch (not bacterial culture!)
- Staph aureus/pseudintermedius (NB. superficial pyoderma can be painful) > cytology
- rarely strep infections
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Which horses are predisposed to med fever?
White limbs
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When do cattle get rain salad/mud fever?
Serious tick infestation (Africa severe form)
- allows opportunistic Dermatophylsis congolensis
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What does Dermatophylsis congolensis cause I'm other species ?
Rain scald
Sheep wool something
Cattle
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What is mud ever also known as?
Mud rash
Greasy heel
Pastern folliculitis
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Management and treatment of mud fever?
*Look up papers*
Management and husbandry changes
- chorioptes/ringworm/other pahtogens in mixed infection eradicated
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What are aural plaques?
- papillomavirus infection
- hyperkeratotic plaques
- concave aspect pinnae
- common esp. yearlings and older
- Simulan spp. (midges) = vectors
- often persist but do not bother horse!!
- therapy = observation, do not tx unless causing problems!
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Why is dermatophytosis treatement always indicated?
Zoonotic and contagious
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Which species cause ringworm in horses?
- trichopyton
- m equinum and m gypseum
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Pathogenesis of ringworm?
Resolvves in healthy horse within 5-6 weeks
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CLinical signs dermatophytosis?
- may be pruritic
- same principles as SA (hair pluck/brush submit for fungal culture)
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Tx ringworm?
> NOTHING LIC IN HORSES
> offlicense:
- topical griseofulvin/potassium iodide
- malaseb
- isolation and hygeine
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Vax for dermatophytosis in the hrose?
No
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What is a comon signs of horse with allergy?
- urticaria +- pruritis
> culicoides/food/atopic/{contact dermatitis?}
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Potential immune mediated/autoimmune skin disease in horse?
- pemphigous foliacious (often accompanied by swelling and oedema)
- erythema multiforme [reaction pattern, not Dx] (may look = urticaria but urticaria will pit on pressure, erythema will not pit)
- adverse drug reactions
- vasculitis [reaction pattern, not Dx] (purpura haemorrhagica)
- alopecia areata (immune attack hair roots)
> reaction patterns may indicate neoplasia, infection etc.
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What is PPID?
- cushings
- pituitary pars intermedia dysfunction
- hyperplasia of pituitary pars intermedia
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clinical signs of PPID?
- old horses/ponies
- PUPD
- lethargy
- poor thriving
- 2* infections ^?
- hirsuitism
- laminitis
> MORE SEE SLIDE
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What are systemic granulomatous diseases?
- or chronic eosinophilic enteritis (may be same thing or slightly different diseases?)
- also known as equine sarcoidosis (NOT RELATED TO SARCOIDS)
- wasting disease
- skin and GI affected
- aetiology unknown (hairy vetch? mycobacterium? viral antigen?)
- grave prognosis
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Tx systemic granulomatous diseaase? Prognosis?
- change feed
- systemic GC months
- spontaneous recovery?
> prog grave
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Clinical sings and dx of systemic granulomatos disease?
- exfoliative dermatitis (scaling)
- crusting
SEE SLIDE ADD MORE
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How sudden onst is systemic granulomatous disease?
Acute onset v sudden onset
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How id dx systemic granuloatous?
- liver function tests
- histopath
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WHat 3 factors needed for photosensitisation? What 2 forms exist?
1* ( st. johns wort, phenothiazine)
2* (phylloerythrin due to liver disease)
> UV + poorly pigmented skin+ photodynamic agent in skin all needed
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What photo induced disease are white limbs susceptable to?
- leucocytoclastic vasculitis
> acute onset erythema, oozing, crusting
> v painful
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Dx. leucocytoclastic vasculitis?
- biopsy
( sedate first!!)
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3 possible groups of nodular skin issues?
1. sterile (often harmless, little known about them)
- collagenolytic granuloma
- cutaneous mastocytosis
- axillary nodular necrosis
- unilateral papillomatosis
2. infectious(microbial/parasitic - can be tx)
- botryomycosis
- habronemiasis
- dermatophilosis
- dermatophytosis
3. neoplastic
- malignant
- benign
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What is eosinophilic granuloma also known as?
- eosinophilic grnauloma
- nodular necrobiosis
- SEE SLIDE
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CLinical signs eosinophilic granuloma?
see slide
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Dx collagenolytic granuloma?
- history (not v speciffic)
> afge, speed of onset, seasonality, tx, systemic disease
- tests
> fungal/bacterial culture
> FNA cytology
> histopath for definitive dx
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Ddx collagenolytic granuloma?
See slide
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Is collagenolytic grnauloma harmful to horse?
No
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Tx collagenolytic granuloma
- leave alone
- surgical excission if few
- GCs (systemic, intralesional, sublesional)
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Prognosis collagenolytic granuloma?
see slife
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See slide for sarcoid types Ddx
***
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