EQM II Lecture 21

Ulceration; erosive/productive lesion; raised, broad based, white-pink; cobbled/cauliflower-like surface; Mets 2-18%

Genetic test, homozygous R/R 4-5 x more likely; most frequent: eyes, external genitalia; thickening, mild exfoliation

Face fly (M. autumnalis); Stable fly (Stomoxys); nematode larvae (Habronema); hypersens. rxn, chronic non-healing wound

Face fly; Nematode worm (Thelazia lacrymalis); Eye glands, ducts, irritation, infection

Winter; multiple horses; sucking and biting; Stressors: stocking density, poor feed quality, gestational status

Non-neoplastic: eosinophilic granuloma, urticaria

Tx P: cryotherapy, autgenous vxn; Tx AP: imiquimod (aldara 3M) NSAID local immune defense modifier 3x/wk, EO wk 2-4m

Lesions: ulcers, nodules, granuloma (proud flesh); Dx: bx, PCR; tx: ivermectin (initial + 2wk); topic/systemic steroids

C. bovis; leg; most common; draft horses

Abnormal coat length and density; abnormal pigmentation

Scaling, crusting, ulceration, alopecia; thickened skin; chorioptic: stamp feet, rub; part of pastern dermatitis complex

S. scabei var equi; body - thin hair; rare, most severe

Summer; individual sensitivity; dorsal, ventral, combo; sweet itch, summer itch, summer eczema; seasonal cause

Medical: intralesional (triamcinolone or methylprednisolone), systemic

Hypersensitivity, atopic dermatitis (insects); Infectious: staphylococcal pyoderma; dermatophytes

DNA vectors (eqIL 12 + 18); canine melanoma vaccine (oncept, merial - tyrosinase)

Withers; hypersensitivity (seasonal); silicone coated needles; located anywhere; nodular, singular or multiple

Most common sign of cutaneous dz; most often hypersensitivity reaction or ectoparasites (lice, mange/mites)

Fly control; topical wound care; debulking may be needed; prevention: remove manure, insect control

Horse, deer (Tabanid) fly; EIA virus; anemia, thrombocytopenia, chronic carriers

Tx: reduce itching, control immune response

Underlying health issue; winter coat, feathering; pruritis + self-trauma; winter (carrier animals); multiple animals

General, skin, record; background, signalment, husbandry, routine care, recent tx, history of contagion, details of dz

E: heal without scar; Infectious: dermatophilus congolensis, habronema spp.; Immune-mediated: adverse drug rxn

Dx: hx (season), signs, exclusion; intradermal testing, serum allergy test; Tx: management, reduce exposure, fly control

Eye (3rd eyelid, medial canthus); male genitalia (sheath, urethral process); lower extremeties

MM abrasions; direct, indirect, insect transmission; external/internal abscess, ulcerative lymphangitis; Dx: hx, signs

Hematopinus asini; thick hair; Anoplura; mane, tail, fetlock/pastern

Location based on flies; pruritis, skin thickening, scaling, crusting, hives, hair loss; rubbing, secondary infection

Feed supplements (omega 3 and 6 FA)

Dx: tx response; Tx: avoid/remove cause, spontaneous resolution; corticosteroids (antihistamine); epinephrine (systemic)

Cause: type 1 hypersensitivity to culicoides (saliva); breed: any, icelandic; possible genetic factors; discomfort

Acetate strips; bx; microfilarial preparation; allergy testing

Pythium insidiosus (fungus/mold); leg; swamp cancer, florida horse leeches; uncommon; hot humid weather + break in skin

Tumor, unpigmented skin, breed; tumor of squamous epithelial cells; 2nd most common tumor in horse; UV light, genetics

Manure: remove, cover, locate away from stables, spread thinly on non-grazing pastures; Water: avoid wet bedding

Water: avoid any accumulation around pastures, stables, paddocks; food + other: remove excess food + organic debris

Biting midges (Culicoides), OTHERS; hives, intense itching, abrasions, ulcerations, infections

Tx: sx (excision, cryo); Medical: chemo (inj. or beads, cisplatin, mitomycin C), microwave energy, piroxicam

Dx: skin scraping; tx: lime sulfur 1x/wk for 1 month; OP spray; fipronil spray; ivermectin (14d apart), moxidectin

Habronema, Draschia; extremities; genitalia; eye; equine summer sore; H. microstoma, muscae, D. megastoma

Rapid onset of wheals, pruritis; back, neck, flank, eyelids, legs; multifocal edema, 0.5-3cm diameter; Dx: hx, signs

Color 80% of gray horses; homozygotes > heterozygotes; breed (arabian, lippizaner, percheron); under tail, lips, limbs

Tumor; grey horses; any location; exposure to sunlight; disturbance in melanin metabolism - graying; age 67% > 15 yr

Coat brushings, skin scraping; fungal + bacterial culture; KOH preparation; dermatophilus preparation; cytology

Horses at risk: older; unpigmented skin around mucocutaneous junction (certain breeds); Belgian WB + draft, Haflingers

Tx: difficult: debulking, chemotherapy, topical; vaccine

Hypersensitivity rxn, granulomatous rxn; stomach: adult - mild gastritis; Cutaneous/conjunctival: larvae deposited

Trombiculoid, forage mite; summer, fall, straw

+/- exudate, +/- pruritis, +/- mineralized; Dx: hx, signs, aspirate, bx; Tx: may regress spontaneously

Aural plaques: form of papilloma (inner pinna of ear, genitalia, mammary gland); Tx P: crush, pinch, sx removal

Helpful to use standardized form to ask questions -> systematic approach

Damalina equi; thin hair; Mallophaga; lateral aspect neck, flanks, base of tail

Topical creams (corticosteroids); shampoo (colloidal oatmeal 1x/wk); systemic corticosteroids; antihistamines

Ultra-fine netting; fans (overhead + stall); reduce moisture; stabling (dusk to dawn); physical barrier (fly mask, wrap)

Cutaneous, subcutaneous, GI, respiratory, multisystemic; tumor like growth following lesion; Dx: histopath, ELISA test

Bot flies; burrow into lip; tongue; gasterophilus

Dx: white exam coat; Tx: systemic: ivermectin q 2wk for 3-4 tx (ONLY sucking lice); moxidectin q 4wk for 2 treatments

Dermal melanoma (deep dermis); dermal melanomatosis; malignant; black, gray; solitary, discrete, firm, spherical or flat

Summer sores; eyeworms; onchocerciasis; bots; pigeon fever; EIA; EEE, WEE, VEE, WNV; Hypersensitivity

D. equi, D. caballi; body, eyelid, muzzle; rare

House, horn, stable flies; Corynebacterium pseudotuberculosis; External or internal abscess; ulcerative lymphangitis

Can help establish a R/O list

Hyperthermia (38-43C); electrochemo (less); cimetidine 2.5mg/kg q 8h for 3wk past resolution; monoclonal Ab

Ext. genitalia; ear, eyelid, neck, parotid gland, guttural pouch; benign melanocytic nevi (sup. dermis, dermoepidermal)

Mosquitoes; encephalomyelitis

Dx: clinical, bx; Tx: sx excision, cryosx, radiofrequency, radiation; chemo: 5-fluorouracil, mitomycin C, cisplatin

Allergic; body; hypersensitivity, mast cell degeneration, histamine release, allergen, medication, vxn, insect bite

P. ovis, P. cuniculi; mane; long hair; rare

Pruritis; nodules, tumors, swellings; ulcerations + erosions; papules, pustules, vesicles; scaling + crusting

Biting midges (Culicoides); Onchocerca cervicalis; Microfilaria in skin (midline); adults in nuchal ligament

Fly spray system; fly traps; use insecticide w/ 2% permethrin; fly predators; feed-through

Coalesce, cobblestone appearance; 95% no significance; progress with age; metastasis; Dx: signs, aspirate, biopsy

Topical: powders, baths, sprays; pyrethrins, synthetic pyrethroids, OP coumaphos, fipronil q 7-10d 2-5x

Dx: U/S, synergistic hemolysin inhibition; Tx: drainage, AB if internal or UL; px depends on form; biosecurity prevents!

Desensitization (30% effective)

Secondary lesions + often get infected; U: complete loss of epidermis, often leave scars; E: partial epidermis loss

Chorioptic; Sarcoptic; Psoroptic; Demodectic; Harvest mite (Trombiculoid), forage mite; pruritis, papules, erythema

Infectious: C. pseudotuberculosis, habronema species, pythiosis; Neoplasia: sarcoid, SCC, melanoma

C. pseudotuberculosis; worldwide; reservoir: ground, feces, hay, shavings; entry: small scrapes/wounds in skin

Papilloma: warts in young animals, variable in size + #; spontaneous regression, transformation not excluded

Adults in stomach, eggs hatch in GIT or envir.; larvae deposited on horse by flies (M. domestica + Stomxys calcitrans)

Food + other: clean feeding area; close garbage containers

Clean fomites!!! avoid overcrowding, poor nutrition, diseases

Immune-mediated: contact irritant of hypersensitivity, photosensitivity, purpura hemorrhagica, vasculitis; SCC neoplasia

Young, old, sick; dry scaly skin, patchy alopecia, crusted ulcerations; anemia; Dx: inspection, hand lens (warmth helps)