Equine dermatology pt 1 Flashcards
functions of skin as an organ
§Shape and form
§Enclosing barrier
§ Temperature regulation
§Produces adnexa
§ Reservoir
§ Immunoregulation
§Sensory perception
layers of the skin from top to bottom
- stratum corneum > dead keratinocytes
- stratum lucidum
- stratum granulosum > lamellar granules
- stratum spinosum > keratinocytes, sparse langerhans cells, melanocyte at base
- stratum basale
- dermis
what is a merkel cell? where do we find it
§Slow-adapting mechanoreceptors
- in the stratum basale, connect to sensory neuron
melanocytes are derived from
neural crest
what is a langerhans cell
§ Dendritic, antigen-presenting cell
what is the function of the basement membrane zone
§Anchors epidermis to dermis
what do we find in the dermis
§Collagen and elastin § Fibroblasts
§Dermal dendrocytes
§Phases of hair growth
§ Anagen: Growth phase
§ Catagen: Transitional phase
§ Telogen: Resting phase
physical exam for skin issue includes:
§Perform complete examination
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§Skin lesions and distribution:
§Primary lesions
§Secondary lesions
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§Remember to check:
§Mucous membranes
§Mucocutaneous junctions
§Inguinal region
§Feathered limbs
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§Record lesions and measure!
§Disorders of pigmentation
- leukoderma disorders
§ Vitiligo
§ Onchocerciasis
§Lupus erythematous
§Pressure sores
§ Burns, freezing, UV
§Disorders of pigmentation
- leukotrichia disorders
§ Reticulated
§ Spotted
§ Hyperesthetic
Disorders of hair
§Mane and tail dystrophy
§Curly coat
§ Hirsutism
§Alopecia areata
§Anagen defluxion
§ Telogen defluxion
§Naked Foal Syndrome
what is a Macule
§ Erythema, hyper- or hypopigmentation
§ Up to 1cm in diameter
§ Not raised
what is a patch
§ Same appearance as macule
§ Greater than 1-2 cm
what is a papule
§ A circular, solid erythematous elevation of the skin up to 1cm in diameter
what is a plaque
§ Larger, flat topped elevation of coalescing papules
what is a nodule
§ Large papule, >1cm
§Raised and may extend into dermis
what is a pustule
§Small accumulation of purulent exudate
what is wheal
§ Raised elevation of skin due to dermal edema
§Pitting edema
what is a vesicle
§ Elevation in epidermis filled with clear
fluid
§ Up to 1cm in size
what is a bulla
§ Vesicle > 1cm in size
what is an erosion
§ Partial loss of epidermis
§ Excoriation= linear erosion
what is an dermal ulcer
§ Complete loss of epidermis and partial loss of dermis
EXUBERANT GRANULATION TISSUE
- how does it arise
- anatomic location most common
- issues
- Tx
§Granulation= phase of wound healing §Overproduction of fibroblasts
> Exuberant granulation
§Most common in distal limbs §Prevents further healing §Requires surgical debridement
pediculosis in horses
- signs
- agents
- season
- Tx
§ Species specific, obligate parasites
§Severe pruritus
§Damalinia equi- Biting louse
§Haematopinus equi- Sucking louse §More common in winter
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§ Treatment
§200ug/kg oral ivermectin every 2 weeks x 3 §500ug/kg topical eprinomectin once weekly x 4
§Pyrethrin spray/ powder every 14 days twice
agents of mange in the horse
§ Sarcoptes scabei var. equi
§ Psoroptes equi
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§Chorioptes bovis
Sarcoptes scabei var. equi
- character, contagion, signs
- anatomic locations
§ Highly contagious and zoonotic
§ Burrowing mite
§ Pruritic
§ Head, neck, and shoulders to generalized
Psoroptes equi
- type of mite, signs, anatomic locations
§ Non-burrowing mite
§ Pruritic
§ Face, ears, areas with high hair density
mange due to Sarcoptes scabei var. equi and Psoroptes equi
Tx
§ 200ug/kg oral ivermectin twice 14 days apart
§ 400ug/kg oral moxidectin once
Chorioptes bovis clinical signs, where found
Mange
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§Survives in environment
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§ Clinical signs:
§ Severe pruritis
§ Erythema
§ Alopecia
§ Excoriation
§ Scales/ crusts
§ Lichenification
chorioptic mange, Dx, Tx
Diagnosis
§Scrape non-traumatized areas
§Evaluate under microscope
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Treatment
§Remove all feathers
§Bathe with medicated or oatmeal shampoo
§ Topical eprinomectin or fipronil
§Oral ivermectin or moxidectin
§ Treat all horses and premise
habronemasis
- common name
- agents
- season
- signalment
“Summer sores”
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Etiology
§ Habronema muscae
§ Habronema majus
§ Draschia megastoma
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Spring and summer
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Increased risk
§ Arabians
§ Grey horses
§ Coat color dilutions
habronemiasis clinical signs
§Ulcerated lesion
§Non-healing wound
§ Contains gritty, yellow granules
habronemiasis Dx, Tx
Diagnosis
§ Biopsy
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Treatment
* Oral ivermectin or moxidectin
* Topical care:
§Compounded ointment
§Surgical debridement
§Bandage if possible
§Fly control
