Equine dermatology pt 2

Question 1

onchocerciasis
- agent
- anatomic location
- season
- reaction

Answer 1

§Onchocerca cervicalis
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§Lives in ligamentum nuchae
§Microfilariae migrate to skin
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§ Seasonal
§Spring and summer
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§Hypersensitivity reaction

Question 2

onchocerciasis
- clinical signs
- lesion distribution
- Dx

Answer 2

Clinical signs
§ Alopecia > scales and crusts
§ Pruritis > excoriated/ulcerative lesions
<><>
Distribution
§Face
§ Neck/chest
§ Ventrum
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Diagnosis
§ Skin biopsy

Question 3

onchocerciasis treatment, adverse reactions?

Answer 3

§ Oral ivermectin or moxidectin
> Up to 2-3x/ month
<><>
25% adverse reactions
§ Ventral midline edema or pruritis
§Umbilical edema
§Eyelid edema
§Fever

Question 4

horse pinworms
- agent
- anatomic location
- clinical signs
- Dx
- Tx

Answer 4

§Oxyuris equi
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§Adults live in colon
§Females lay eggs in the peri-anal area
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§Clinical signs
§ Pruritis
<><>
§ Diagnosis
§ Tape test
<><>
§ Treatment
§Clean perineum and all surfaces
§ Deworm

Question 5

dermatophilosis
- common name, agent
- risk factors
- how the organism reproduces

Answer 5

Rain rot or rain scald
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Etiology
§Dermatophilus congolensis
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Risk factors
§Chronic wet conditions
§Chronic damp coat
§Damaged skin
§ Immunocompromise
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Zoospores released in high moisture
§Migrate into the skin

Question 6

dermatophilosis
- signs
- distribution
- sequelae

Answer 6

Acute or chronic superficial pyoderma
<>
Clinical signs
§Regional or generalized papules and crusts
>Paintbrush lesions
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Distribution
§ Dorsum, face, neck, distal limbs
<>
Severe disease
§Secondary bacterial infection

Question 7

dermatophilosis Dx, Tx

Answer 7

Diagnosis
§Direct smear
§Saline slide prep of crusts
§Skin biopsy
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Treatment
§Dry environment
§Antibacterial shampoo
§ Topical antibiotic cream
§Clean all grooming supplies

Question 8

superficial pyoderma
- etiology / agent
- seaseon
- pathogenesis
- clinical signs
- distribution

Answer 8

Etiology
§ Coagulase + Staphylococcus spp.
§ Streptococcus spp.
<><>
§ Summer
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Disruption of skin
§ Opportunistic invasion
§ Multiply in hair follicle
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Clinical signs
§ Crusts, pruritis, alopecia
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Distribution
§ Under tack
§ Pasterns

Question 9

superficial pyoderma
- Dx
- TX for milk, moderate, severe cases

Answer 9

Diagnosis
§ Bacterial culture
§ Cytologic examination
§ Skin biopsy
<><>
Treatment
§ Mild- self-limiting
§ Moderate
> Topical anti-microbial shampoo
§ Severe
> Topical + systemic antimicrobials

Question 10

abscessation
- primary reasons / agents
- secondary reasons

Answer 10

Primary infections
§ Streptococcus equi subsp. equi §Corynebacterium pseudotuberculosis
§ Actinomyces
§Clostridium spp.
<><>
Secondary infections
§ Trauma/ wound
§ Intramuscular injection
§ Local extension

Question 11

corynebacterium pseudotuberculosis
- clinical lesion forms
- Dx
- Tx

Answer 11

Clinical forms
§External abscesses
§Internal abscesses
§Ulcerative lymphangitis
§Superficial or deep pyoderma
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Diagnosis
§Clinical appearance
§Culture and sensitivity
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Treatment
§ Maturation, drainage, rupture of abscesses §Local limb therapy
§Long-term systemic antimicrobials

Question 12

clostridial myo/dermonecrosis
- risk factors
- clinical signs
- Dx
- Tx

Answer 12

Risk factors
§Skin or mucosal wound
§Intra-muscular injection
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Clinical signs
§ Acute, firm swelling
§ Tissue sloughing
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Diagnosis
§Culture +/- histopathology
Treatment
§Surgical debridement
§High dose penicillin or metronidazole

Question 13

viral papillomatosis
- etiology
- age
- transmission

Answer 13

Etiology
§Equus caballus papillomavirus
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Young horses < 4 years
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Transmission
§Direct contact with infected horses
§Indirect contact > fomites
§Black flies

Question 14

viral papillomatosis
- wart progression
- aural plaques > where they are, appearance, progression
- Tx

Answer 14

Warts
§Progress for 4-8 weeks
§Spontaneously regress in 3-4 months
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Aural plaques
§Concave part of pinnae
§ Smooth or raised, progressive lesions
§Do not spontaneously regress
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Treatment
§Benign neglect
§Surgical excision
§ Cryonecrosis
§ Immunomodulators
§ Topical caustic agents

Question 15

vesicular stomatitis
- etiology
- other animals? significance?
- Transmission
- clinical signs
- Dx
- outcomes

Answer 15

§ Etiology
§ Vesicular stomatitis virus
<>
§Reportable and zoonotic
§ Ruminants, camelids, swine, humans
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§ Transmission
§ Flies
§Direct contact
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§Clinical signs
§Vesicles > ulcerative and erosive lesions
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§ Diagnosis
§ Viral isolation
§ Serology
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§Short duration and self-limiting

Question 16

equine coital exanthema
- etiology
- transmission
- leasions, locations
- Tx

Answer 16

Etiology
§ Equine Herpes Virus-3
<><>
Transmission
§ Direct contact
§ Fomites
§ Insects
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§ Shallow, ulcerated areas
§ Vulva and perineum of mares
§ Penis and prepuce of stallions
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Treatment
§ Corticosteroids contra-indicated
§ Remove from breeding program and isolate

Question 17

dermatophytosis
- etiology
- transmission
- risk factors
- clinical signs

Answer 17

Etiology
§ Trichophyton equinum or mentagrophytes §Microsporum gypseum or canis
<><>
Transmission
§Direct contact or fomites
<><>
Risk factors
§Poor husbandry
§ Immunocompromise
§Chronic damp coat
<><>
Clinical signs
§Alopecia with scaling and crusting

Question 18

dermatophytosis Dx, Tx

Answer 18

Diagnosis
§Microscopic exam of hair shafts
§Skin biopsy
§Fungal culture
§ PCR
<><>
Treatment
§Spontaneous resolution 1-6mo
§ Weekly for 6-8 weeks:
>Anti-fungal or accelerated H2O2 shampoo
> Leave-on 0.2% enilconazole rinse diluted 50%

Question 19

pythiosis
- etiology
- risk factors
- pathogenesis

Answer 19

Etiology
§Pythium insidiosum
<><>
Risk factors
§Endemic area
§Standing inland water
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Pathogenesis
§Motile zoospores or hyphae
§Enter via wounds in submerged skin

Question 20

pythiosis
- lesions
- Dx
- Tx

Answer 20

Cutaneous form
§ Granulomatous, nodular, ulcerated mass
§ Resemble tumors
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Kunkers- cores of necrotic gray-yellow material
§ Specific to horses
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Diagnosis:
§ Presence of agent in wet mount prep
§ Detection of anti-P. insidiosum antibodies
§ Detection of DNA by PCR
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Treatment
§ Radical and complete excision
§ Immunotherapy

Question 21

what is utricaria? precipitating factors?

Answer 21

hives
§ Type I and II hypersensitivities
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Precipitating factors
§ Feed/supplements
§Inhalant/ contact allergens
§ Transfusion reaction
§ Temperature
§ Pressure
§ Exercise
§ Pathogen-induced
§Insect bites/ stings
§ Stress-related
§ Idiopathic

Question 22

insect bite hypersensitivity
- implicated species
- risk factors

Answer 22

Implicated insect species
§Culicoides sp
§Black flies & buffalo gnats
<><>
Risk factors
§> 3-4 years of age
§ Icelandic, Friesian, Arabian,
Quarter horse
§Familial history
§Imported at older age

Question 23

insect bite hypersensitivity clinical signs, sequlae, distribution

Answer 23

§ Pruritis
§Mane and tail trauma
> Excoriations, erosions, alopecia
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§ Chronic
> Lichenification and pigment changes
<><>
§Secondary bacterial infections common
<><>
Distribution
§Insect species dependent

Question 24

insect bite hypersensitivity Dx, Tx

Answer 24

Diagnosis
§Clinical exam
§Skin biopsy
§Intra-dermal skin testing
<><>
Treatment
§ Allergen specific immunotherapy
§ Systemic
> Corticosteroids
> Anti-histamine
§ Topicals
> Colloidal Oatmeal shampoos/soaks

Question 25

insect bite hypersensitivity prevention

Answer 25

§ Turn out schedule
§Box fans in stalls
§Move away from water
§Insect control
> Topical insect repellents
> Timed insecticide misters
> CO2 insect traps
> Protective sheets and masks