Equine Derm

Question 0

Non-infectious equine skin diseases?

Answer 0

• allergies
• immune mediated
• endocrinopathy
• misc
• neoplasia

Question 1

Potential infectious skin diseases of horses?

Answer 1

• ectparasites
• dermatophilosis
• folliculitis
• fungal (dermatopyhtosis)
• viral (aural plaques)

Question 2

Which ectoparasites affect horses? Esp common?

Answer 2

• 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

Question 3

Where is chorioptes often seen?

Answer 3

• feathered hgorses
• pastern dermatitis
• peaks in winter

Question 4

Clinical signs chorioptes?

Answer 4

• pruritis, erythema, crusts, papules

Question 5

Tx chorioptic mange?

Answer 5

• fipronbil spray (repeat monthly, lots needed)
• avermectins (efficacy controversial)
• permethrins/pyrethroids (flumethrin acaricidaL)
  > clip feathers

Question 6

Clinical signs of lice infestation?

Answer 6

• pruritis variable

- identify parasites!! people overlook

Question 7

Tx lice infestation

Answer 7

• fipronil spray
• syth pyrethroids
• systemic ivermectin (H. Asini sucking lice)

Question 8

are lice contagious?

Answer 8

Yes but species specific so only horses need treating

Question 9

How may flies cause problems in horses?

Answer 9

• bites and stings
• infected woudns
• hypersensitivity (esp culicoides sweet itch)
• laral myasis
• disease transmission (habronemiasis and onchocerchiasis)

Question 10

What worms cause itchy bottoms?

Answer 10

• pinworms
• oxyuris equi
  > adults migrate from LI out of anus to lay eggs
• self trauma

Question 11

Most common skin allergy in horses?

Answer 11

Sweet itch

- insect bite hypersensitivity

Question 12

Where is sweet itch seen? WHen?

Answer 12

USually dorsal but ventral fly also exists

- always seasonal! Not winter

Question 13

Clinical signs of sweet itch??

Answer 13

• papules, crusts, skin thickening, alopecia

- seasonal pruritis

Question 14

What aged hroses sweet itch affect?

Answer 14

• > 6 months

Question 15

Ddx sweet itch?

Answer 15

• oxyuris equi
• insects
• other allergies

Question 16

Is intradermal testing for sweet itch indicated?

Answer 16

• shows exposure not hypersensitivity

Question 17

Does ASIT work for sweet itch?

Answer 17

No!!

Question 18

Tx sweet itch?

Answer 18

• 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!]

Question 19

Most common bacterial disease on the horse? How are these diagnosed? `

Answer 19

• 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

Question 20

Which horses are predisposed to med fever?

Answer 20

White limbs

Question 21

When do cattle get rain salad/mud fever?

Answer 21

Serious tick infestation (Africa severe form)

- allows opportunistic Dermatophylsis congolensis

Question 22

What does Dermatophylsis congolensis cause I’m other species ?

Answer 22

Rain scald
Sheep wool something
Cattle

Question 23

What is mud ever also known as?

Answer 23

Mud rash
Greasy heel
Pastern folliculitis

Question 24

Management and treatment of mud fever?

Answer 24

*Look up papers* Management and husbandry changes - chorioptes/ringworm/other pahtogens in mixed infection eradicated

Question 25

What are aural plaques?

Answer 25

- 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!

Question 26

Why is dermatophytosis treatement always indicated?

Answer 26

Zoonotic and contagious

Question 27

Which species cause ringworm in horses?

Answer 27

- trichopyton | - m equinum and m gypseum

Question 28

Pathogenesis of ringworm?

Answer 28

Resolvves in healthy horse within 5-6 weeks

Question 29

CLinical signs dermatophytosis?

Answer 29

- may be pruritic | - same principles as SA (hair pluck/brush submit for fungal culture)

Question 30

Tx ringworm?

Answer 30

``` > NOTHING LIC IN HORSES > offlicense: - topical griseofulvin/potassium iodide - malaseb - isolation and hygeine ```

Question 31

Vax for dermatophytosis in the hrose?

Answer 31

No

Question 32

What is a comon signs of horse with allergy?

Answer 32

- urticaria +- pruritis | > culicoides/food/atopic/{contact dermatitis?}

Question 33

Potential immune mediated/autoimmune skin disease in horse?

Answer 33

- 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.

Question 34

What is PPID?

Answer 34

- cushings - pituitary pars intermedia dysfunction - hyperplasia of pituitary pars intermedia

Question 35

clinical signs of PPID?

Answer 35

- old horses/ponies - PUPD - lethargy - poor thriving - 2* infections ^? - hirsuitism - laminitis > MORE SEE SLIDE

Question 36

What are systemic granulomatous diseases?

Answer 36

- 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

Question 37

Tx systemic granulomatous diseaase? Prognosis?

Answer 37

- change feed - systemic GC months - spontaneous recovery? > prog grave

Question 38

Clinical sings and dx of systemic granulomatos disease?

Answer 38

- exfoliative dermatitis (scaling) - crusting SEE SLIDE ADD MORE

Question 39

How sudden onst is systemic granulomatous disease?

Answer 39

Acute onset v sudden onset

Question 40

How id dx systemic granuloatous?

Answer 40

- liver function tests | - histopath

Question 41

WHat 3 factors needed for photosensitisation? What 2 forms exist?

Answer 41

1* ( st. johns wort, phenothiazine) 2* (phylloerythrin due to liver disease) > UV + poorly pigmented skin+ photodynamic agent in skin all needed

Question 42

What photo induced disease are white limbs susceptable to?

Answer 42

- leucocytoclastic vasculitis > acute onset erythema, oozing, crusting > v painful

Question 43

Dx. leucocytoclastic vasculitis?

Answer 43

- biopsy | sedate first!!

Question 44

3 possible groups of nodular skin issues?

Answer 44

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

Question 45

What is eosinophilic granuloma also known as?

Answer 45

- eosinophilic grnauloma - nodular necrobiosis - SEE SLIDE

Question 46

CLinical signs eosinophilic granuloma?

Answer 46

see slide

Question 47

Dx collagenolytic granuloma?

Answer 47

``` - history (not v speciffic) > afge, speed of onset, seasonality, tx, systemic disease - tests > fungal/bacterial culture > FNA cytology > histopath for definitive dx ```

Question 48

Ddx collagenolytic granuloma?

Answer 48

See slide

Question 49

Is collagenolytic grnauloma harmful to horse?

Answer 49

No

Question 50

Tx collagenolytic granuloma

Answer 50

- leave alone - surgical excission if few - GCs (systemic, intralesional, sublesional)

Question 51

Prognosis collagenolytic granuloma?

Answer 51

see slife

Question 52

See slide for sarcoid types Ddx

Answer 52

***

Question 53

Which other species may get sarcoids?

Answer 53

- felines (esp. farm cats, zoo cats too)