Equine Med- Derm 1

drraythe's version from 2016-04-29 15:33


Question Answer
If I say grey horse, you say...melanoma
what you thinkin? rain rot/scald, dermatophilus congolensis
what you thinkin? FEATHERED HORSE--- and itching and hair loss--- if feathered, more likely to be chorioptic mange
what you thinkin? Note that this is a WHITE HORSE with a white hoof. more susceptible to damage of sun, environment, bacterial inflammation--> "Pastern dermatitis"
what are icelandic horses (not ponies even tho theyre small) predisposed to?Sweet itch! (no Culicoides midges in iceland mean they are evolutionarily particularly susceptible to this)
what are you more likely to think a young horse would get (general) versus old?YOUNG: hereditary issues. OLD: allergies
2 things white skinned horses are prone to? dermatitis, SCC
What is going on with this horse? (explain a bit about it, how serious is this?)'s an ARABIAN horse!! and it has fading spots on it. Basically the pigment is going away, it will get progressively worse, but doesn't cause hard (owners care tho)
how might you think about these two very similar bumps on these two different horses? what do you think about biopsying them? one is a GREY HORSE-- this is most likely (and we were told it is) MELANOMA. The other horse is not grey and it is most likely a sarcoid. Bx: Note: first, think of the location. This is where the saddle strap goes, so it is rubbing there a lot. Also, if you take a bx of a sarcoid, they tend to get even more aggressive. Might want to consider FNA bc for melanoma this is definitive anyway (but basically if wanna sx remove you will need huge margins)
what is senecio?This is pyrrolizidine alkaloid toxicity (Liver, megalocytes.)
What are these weird things? They kinda look like ringworm, but arent ringworm? This is occult sarcoids. So if they have been treating ringworm for a year to no avail, might be time to consider bx for sarcoids
What does it mean when they look like this, losing patches of hair? Alopecia areata
Which problem tends to cause pruritus and resulting excorations of the lower limb? Who tends to get this problem?Chorioptic mange- common in feathered horses.
a wound/lesion that "grows" ddx? (2)Sarcoid, habronemiasis
what is this most likely? Dermatophytosis (if not responding to tx, remember to consider occult sarcoids)
what is important to remember about dermatophytosis?its ZOONOTIC
remember which GI problem can cause skin lesions?The type of IBD known as MEED (need rectal bx)
what is this most likely? possible ddx? why not the ddx tho? This is SCC! Maybe prolpase of 3rd eyelid, but the irregular nature of it suggests it is neoplastic
what do you think this is? ddx? why not ddx tho? This is PHOTOTOXICITY (photosensitivity). Considering the location you might consider chorioptic mange, but it's too severe to be that. Also only the white areas are affected
which external parasite can be seen with the naked eye?Sucking lice
when (seasonal, situational) are lice most commonly found?Most common in the spring (although with thick winter coats they are hard to miss), they are also common on horses who are ADR (poor BCS, etc)
3 tests for allergy testing?(1) elimination diet (2) serum ELISA (3) Intradermal testing
what kinda size needle and syringe would you use for an aspiration biopsy?she said use a fine needle-- like 23G. and syringe should not be big (she said 5cc is good). She said bigger gauge is not necessarily better.
what's this (FNA sample) melanoma
what's this (FNA sample) mast cell
explain how to take a punch bx- prep, procedure, aftercareNO CLIPPING OR SCRUBBING- this distorts the skin and results wont be as reliable. give LA and leave needle in place. Then take the bx, and leave the wound open! they heal by themselves. Also DO NOT USE TWEEZERS, it ruins your bx material.
what is a hereditary condition where you should NOT take a skin bx?Hyperelastosis cutis. hereditary dz. collagen abnormality. No need to take bx- If do, healing will be problematic.
What is going on in this picture- and why do you NOT want to take a bx of it? This is Nodular necrobiosis= eosinophilic granuloma. First off, it is where the saddle is the owner wont be able to ride for quite a while and it will be difficult to heal. They also will go away by themselves with time. To avoid, inc padding under saddle.
how common is sarcoptes in horses, and where does it tend to be?RARE, but if it happens, usually on head and neck.
What time does sweet itch usually happen, and where are the common locations of lesions?sweet itch is an allergy to Culicoides midges- so common in the months where these midges are around (summerish) and have pruritus around tail and mane. Whole neck often involved, and nuchal lig might be involved
what are different types of skin dzs horses can have (based on cause)Parasitic skin diseases, Viral skin diseases, Bacterial skin diseases, Fungal skin diseases, Environmental induced skin diseases, Congenital / hereditary skin diseases, Immune mediated skin diseases

Parasitic skin infections

Question Answer
as a vet in the states what is important to know about chorioptic mange?REPORTABLE
what is the causative agent of chorioptic mange? what does it eat?Chorioptes equi: feeds on skin debris.
Where are lesions of chorioptic mange? what do the lesions look like? what are the CSs?mainly distal limbs: scaling, papules. Causes pruritus, so they will be stamping and rubbing their distal limbs.
How is chorioptic mange transmitted?transmission direct- indirect contact (there are carrier horses)
is chorioptic mange zoonotic?nope!
which type of horses are prone to chorioptic mange?Feathered/draft breeds
**which of the mange mites in most common to see in horses?chorioptic
**how do you identify Psoroptic mange Vs Chorioptic mange vs sarcoptic mange?**look at legs and pedicles! PSOROPTES has long tarsi (legs) and long pedicles. Sarcoptes has short tarsi and short pedicles. Chorioptes has long tarsi and short pedicles.
What mite is this? Chorioptes equi
what dis? Chorioptes equi, often lives with many!
(discussed in class) how do you treat chorioptes?tx mange in dogs with ivermectin. might help in horses a little but not really gonna kill all the mites. can survive off host for week. so need to tx animal AND environment too. Smith suggests fipronil. but cant use some topical products on horses- ike amitraz (use in cattle and tick collars on dogS). but causes impaction of LVC in dogs. salacil (foxim) is what she uses but she doesnt know if its approved in the US. so mention ivermectin, foxim, and fipronil
what is the word for infestation of lice?Pediculosis
do lice cause pruritus?YES! Can be so severe they injure themselves
what is the horse biting louse?Werneckiella equi (Mallophagen) (WERN BITES lol oh lawd)
what is the horse sucking louse?Haematopinus asini (Anoplura) (suck haem)
what condition horse is more prone to lice, why?usually see in temperate climate in winter with poor BCS (so less immunity against normal infections)
What is this thing? You were able to see it on the horse's hair and then you checked it out under the microscope This is a lice nit (egg/eggshell)
be able to tell biting from sucking liceBiting has a big head with powerful jaws, sucking has more narrow mouthpieces
what are the two nematodes which can cause skin probs in horses?Oxyuris equi (pinworms), and Onchocerca cervicalis (onchocerciasis)
what is the fancy name for pinworms, what does it do to the horse and how do you dx? (how do you tx?) *know what lifestage is the jerk inhabits small colon, rectum-adults go out of anus to lay eggs--> tail rubbing. Dx: adhesive tape smear. (tx: sensitive to ivermectin!)
fancy name for thing that causes onchocerciasis, what does it do to the horse, what are clinical signs? *know what lifestage is the jerk.microfilariae (NOT adults) causing diffuse seasonal dermatitis, ventral midline is a common area, chest, withers, face & neck --> alopecia & papules. Pruritus and dermatitis.
who's egg is this? oxyuris equi-- the pinworm
Habronemiasis---> what THREE parasites all cause habronemiasis?Habronema musca, Habronema microstomus, & Draschia megastoma
explain the lifecycle of habronemiasisAdult worms in horse's stomach lay eggs--> eggs in poop--> biting fly (like horse fly) eats poop--> if horse licks fly it is ingested and the larvae which have developed in the fly go to stomach, restart cycle. OR the fly lands on open wounds/medial canthus of eye and deposits flies there= cutaneous/ocular habronemiasis
what does cutaneous/ocular habronemiasis look like?
cutaneous habronemiasis usually presents as..a wound that wont heal
ddx habronemiasis?sarcoid (also a wound that wont heal, esp if in temperate climate)
tx for habronema?ivermectin.. NOTE: some horses based on diff immune reaction-- some horses seem predisposed to develop these lesions, and then they are reservoir to other horses. If tx with ivermectin and they come back, harder to tx with iver again. So in chronic try moxidectin. And then local tx with moxi and steroids. difficult close to eye but in other places can place ointment.
what is this horribleness? Myiasis (Myiasis is infection with a fly larva, usually occurring in tropical and subtropical areas)
what should you look for if you see a big nodule on the horse, or if the hair is standing up kinda weird?tick bites can cause reactions like this- look to see if there is a tick (could be pathogens in the tick or just allergy to the bite itself)