Horse Dermatology Flashcards
Predilection site for Chorioptes.
How to identifty Chorioptes
Limbs and tails.
Chorioptes have long legs as are surface mites
Horse fly genus
Tabanus.
Stomoxys = Stable fly
Treatment for Lice infection in horses
Fibronil spray. Can normally see lice with naked eye
Tail rubbing and self trauma around the tail base would make you suspitious of…
Pinworm infestation (Oxyuriasis) Adult worms migrate from terminal parts of large intestines out of anus to lay eggs.
The equivalent of FAD in horses is known as
Sweet itch (Culicodies). Most common skin allergy in horses. Seasonal pruitis, papules, crusts and skin thickening. Dorsal or vertral midline.
Management changes to help reduce sweet itch
Always check Pin worm status.
Stable between 4 and 8am. Rugs/hoods/ windy dry fields.
Repellents and Longterm insecticides (Pyrethoids)
‘Rail track’ on DiffQuick cytology of horse leg lesion (exudate, matted hair) is indicative of
Dermatophilosis conglenisis. Dorsum or limbs (mud fever)
Aural plaque pathogenesis and treatment
Hyperkeratoic plaques on concave aspect of ear. Common.
Simulium vectors.
DON’T TREAT; INCIDENTAL
Treatment of Dermatophytosis in horses
Healthy host; spontaneous resolution within 5-6 weeks. Pruitic in horse. Fungal culture for diagnosis as yard outbreak needs to be confirmed before.
Pathogenesis of Alopecia areata.
What is the main Ddx
Immune attack on hair bulb needs. Diagnosis by biopsy.
Main Ddx is Dermatophytosis
Main skin change in PPID in horses
Hirsuitism (long hair)
Hyperhyrsosis,
Laminitis.
Hyperplasia of the pituitrary pars intermedia
In a horse with poorly pigmented skin, work up of the skin disease should include
Liver enzymes as Phyllerythrin due to liver disease = secondary ph.
Pathogenesis of Systemic granulomatous disease and Chronic eosinophilic enteritis
Oxfolative dermatitis= generalised scaling, often crusting, alopecia or nodules.
Systemic signs: Severe wasting, fever, icterus, diarrhoea.
An acute onset erythema, oozing, crusting and painful in non-pigmented lower limbs could be…
Leucocytoclastic vasculitis. Need to confirm diag via biopsy before starting immunosuppressive therapy.
Liver enzymes should be checked as only white area affected (rule out Liver disease)
How to differentiate Nodular disease from Urticarial disease
Apply pressure, urticarial disease will pit with pressure.
Collagenolytic granuloma
Cause unknown possibly hypersensitivity to insect bites. Often in saddle area, neck and flanks, Mostly spring and summer.
NOT ALOPCECIA, ULCERTATIVE OR PAINFUIL.
Chronic lesions lead to Mineralisation
Ddx from Collagenolytic granuloma
Papular dermatitis, Staphylococcal folliculitis & furunculosis, dermatophytosis, neoplasia, cutaneous amyloisosis
Equine sarcoids restricted to which layers
Skin and Subcutis. Common at fly predilection sites and wounds.
Six clinical sarcoid entities. Considerations of biopsy
- Occult
- Nodular
- Verrucous
- Fibroblastic
- Mixed
- malevolent
CAN PROGRESS FROM ONE FORM TO ANOTHER WHEN TRAUMATISED THEREFORE CARE WITH BIOPSY
Occult sarcoid
Main Ddx
Flat, eyes mouth hairless areas. Main Ddx: Dermatophytosis, burns, trauma
Nodular sarcoid
Main Ddx
Groin, sheath, eye lid, subcut nodules.
Main Ddx: Fibroma, Melanoma, Collagenolytic, Granuloma, Warble Fly cysts
Verrucous sarcoid
Main Ddx
‘Warty’ Face&Body nodules, thickening.
Main Ddx@ Papillomatosis, Chronic sweet itch, SCC
Fibroblastic sarcoid
Groin, eyelids. limbs. wounds fleshy/ulcerated.
Ddx: Granulation tissue,
Why does care have to be taken when biopsy is taken off suspected equine sarcoid
Diagnostic but may encourage progression. Excisional better than partial. Contradinidicated if lesions static over a long time
