Flashcards in Equine Derm Deck (54)
Potential infectious skin diseases of horses?
- fungal (dermatopyhtosis)
- viral (aural plaques)
Non-infectious equine skin diseases?
- immune mediated
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
Where is chorioptes often seen?
- feathered hgorses
- pastern dermatitis
- peaks in winter
Clinical signs chorioptes?
- pruritis, erythema, crusts, papules
Tx chorioptic mange?
- fipronbil spray (repeat monthly, lots needed)
- avermectins (efficacy controversial)
- permethrins/pyrethroids (flumethrin acaricidaL)
> clip feathers
Clinical signs of lice infestation?
- pruritis variable
- identify parasites!! people overlook
Tx lice infestation
- fipronil spray
- syth pyrethroids
- systemic ivermectin (H. Asini sucking lice)
are lice contagious?
Yes but species specific so only horses need treating
How may flies cause problems in horses?
- bites and stings
- infected woudns
- hypersensitivity (esp culicoides sweet itch)
- laral myasis
- disease transmission (habronemiasis and onchocerchiasis)
What worms cause itchy bottoms?
- oxyuris equi
> adults migrate from LI out of anus to lay eggs
- self trauma
Most common skin allergy in horses?
- insect bite hypersensitivity
Where is sweet itch seen? WHen?
USually dorsal but ventral fly also exists
- always seasonal! Not winter
Clinical signs of sweet itch??
- papules, crusts, skin thickening, alopecia
- seasonal pruritis
What aged hroses sweet itch affect?
- > 6 months
Ddx sweet itch?
- oxyuris equi
- other allergies
Is intradermal testing for sweet itch indicated?
- shows exposure not hypersensitivity
Does ASIT work for sweet itch?
Tx sweet itch?
- anti-inflammatories/antipruritic (antihistamines, GCs)
> 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!]
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
Which horses are predisposed to med fever?
When do cattle get rain salad/mud fever?
Serious tick infestation (Africa severe form)
- allows opportunistic Dermatophylsis congolensis
What does Dermatophylsis congolensis cause I'm other species ?
Sheep wool something
What is mud ever also known as?
Management and treatment of mud fever?
*Look up papers*
Management and husbandry changes
- chorioptes/ringworm/other pahtogens in mixed infection eradicated
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!
Why is dermatophytosis treatement always indicated?
Zoonotic and contagious
Which species cause ringworm in horses?
- m equinum and m gypseum
Pathogenesis of ringworm?
Resolvves in healthy horse within 5-6 weeks