SA Med Exam 2

Antibodies targeted against desmocollin-1 or desmoglein-1 in the desmosomes

type 2

• crusts and pustules of nasal planum, eyes, feet (including claws) and pinna
• pruritus, febrile, depressed
• can also be generalized

retrievers, chows, cats

• histopathology - don't clean the site!
• see acantholytic cells, subcorneal pustules with neutrophils
• CBC shows neutrophilia

remove drug, may need immunosuppressive therapy

TMS, abx, griseofulvin

GSP

collies, shelties

systemic and discoid

Ag-Ab complexes form at the BMZ

type 3

• Depigmentation and alopecia around the eyes, nasal planum, muzzle and pinna
• Can be very crusty, or loss of "cobblestone" appearance on nose

• dolicocephalic or mesaticephalic, but not brachycephalic
• e.g. Siberian Husky, Sheltie, Collie, GSD

histopathology

2-6 years old

cutaneous lymphoma, hepato-cutaneous syndrome

• "interface dermatitis"
• thickening of BM because of Ag:Ab complexes
• pigmentary incontinence
• hydropic degeneration (vacuolated areas)

reduce exposure to sunlight!

• Pred (2x allergy dose) then taper
• azathioprine for a month, then taper (steroid sparing drug)
• Abx at same time medium acting steroids are started
• Gold (esp if endogenous steroids)

bone marrow suppression (esp in cats!)

• Pred
• Dex
• Triamcinolone
• Chlorambucil (because can't give azathioprine)
• Cyclosporine
• Gold (esp if endogenous steroids)

• niacinamide + tetracycline for 1-2 months
• tacrolimus ointment
• topical bethamethasone
• topical sunscreen

vomiting (rare)

expensive ointment that works like cyclosporine but has better skin absorption

Ctenocephalides felis felis

• 21 days
• Can be 12-190 days

75F and 78% relative humidity 

24-36 hours after the first blood meal

1-10 days

>1,000

• 3 stages total, last 5-11 days each
• feed off flea poop
• negatively phototaxic and positively geotaxic
• highly susceptible to heat dryness

• cocoon stage
• most resistant to dessication / elimination
• sticky, so get covered in dust and camouflage
• adults emerge in response to heat, CO2, vibrations, physical pressure

body heat, CO2, vibrations, light, air, host movement

• Feed every 3 minutes
• Mate 8-24hours after emergence
• Lay eggs 24-36 hours after feeding

Permanent ectoparasite

hypersensitivity (type 1 and 4) to flea saliva

pruritus on caudal half of body

• Histamine-like compounds
• Proteolytic, cytolytic and anti-coagulant enzymes
• Complete protein antigens

• genetic predisposition
• duration of exposure
• degree of exposure

• type 1 hypersensitivity (immediate, IgE mediated)
• type 4 hypersensitivity (delayed, T cell mediated)
• cutaneous basophil hypersensitivity

animals with AD

• hx (are they giving flea meds, does the animal go in the water a lot, recent boarding)
• finding flea dirt (= flea poop, stains red on paper)
• PE (pruritus and alopecia caudal to "belt")

• can have neck and face alopecia
• can see miliary dermatitis and eosinophilic skin disease

• CBC (regenerative anemia, eosinophilia)
• biopsy (r/o other diseases)

• eradicate fleas in the environment
• symptomatically tx the patient
• prevent further infestations (must tx all animals!)

• tx secondary infx (malassezia and superficial pyodermA)
• corticosteroids (short course)

• quick kill (reduces allergic rxn)
• acts against >1 life stage, but esp gets adults
• non-irritating, non-toxic
• residual effects

• re apply every 2-4 weeks
• come off with bathing / swimming
• malodorous

• doesn't get washed off
• quicker speed of kill

• expensive
• give once monthly
• +/- flavored

kill adult fleas

kill non-adult flea life stages

• Juvenile Hormone Analogues (JHAs)
• Insect Development Inhibitors (IDIs)

synthetic hormones that cause incomplete larval molts, disrupt embryogenesis

• pyriproxyfen (Vectro3D, AdvantixII)
• S-methoprene (Frontline+)

malformation of chitin cuticle, incomplete larval ecdysis (flea can't emerge, or dies soon after emerging)

Lufenuron (Program, Sentinel)

flea adulticide + larvicide

• inhibits post-synaptic nicotinic receptors
• distribution via translocation

disrupts chloride channels in CNS -> neurotoxicity

• adult fleas and ticks
• can't use on rabbits!

increase Cl- permeability in Glu-gated neuronal Cl- channels -> paralysis

• fleas - adults, larvae and eggs
• HWP

Repellant, fast kill

• variable efficacy and duration
• *toxic to cats*
• breaks down in uv light

neonicotinoid adulticide

adult fleas, ticks, mosquitos

activates nicotinic AchR

neonicotinoid

adult fleas

• most effective flea adulticide
• *very safe*
• gold standard txt for FAD
• starts killing in 30 minutes

only 24 hour effect

100% effect in 4 hours

neonicotinoid

• apply once monthly
• give with a full meal
• AE: vomiting
• *do not give with ivermectin!*

• rotenone (rare)
• -inhibits oxidative phosphorylation
• d-limonene
• -inhibits peripheral sensory n.
• pyrethrins / pyrethroids
• -inhibits Na channels
• carbamates
• -inhibits cholinesterase (reversible)
• organophosphates
• -inhibits cholinesterase (irreversible)

• infection, infestation, allergy
• -also consider heavily perfumed litter boxes, and the role genetics

• eosinophilic granuloma
• lip ulcer (aka rodent, eosinophilic)
• eosinophilic plaque

• see on caudal thighs, oral cavity
• +/- peripheral lymphadenopathy

• CBC: eosinophlia
• histopathology: eosinophilic-derived granulomas that coat collagen fiber (*not collagen degeneration*)

crusts, vesicles, ulcers and swelling on the nasal planum, pinna and footpads

eosinophils + eosinophilic-coated collagen

• corticosteroids
• keep the cat indoors

• PE: ulcerative dermatitis on upper lip
• blood and tissue eosinophilia (but will be neutrophils if biopsy early)
• +/- peripheral lymphadenopathy

• SCC
• herpes virus dermatitis
• rare: staph, dermatophytes, deep fungal infx

• VERY puruitic
• see on abdomen and medial thighs
• +/- peripheral lymphadenopathy

• impression smear: eos
• histopathology: eos in epidermal vacuoles

fleas, food, AD, contact (perfumed litter box)

• tx underlying hypersensitivity
• methylprednisolone q2wks x 3 txts
• cyclosporine (better for eos plaque and granuloma)
• ~EFAs (better for granulomas)
• clavamox (better for plaque, maybe for ulcer)

• V
• lethargy
• secondary infx / pyoderma
• papillomas
• hypertrichosis
• gingival enlargement

encrusted papules reaction pattern

• fleas - most common
• Cheyletiella
• lice
• food allergy
• AD
• dermatophytes
• pyoderma

• tx underlying cause
• anti-inflammatory oral corticosteroids if idiopathic

FAD > AD > food allergy

• genetically predisposed inflammatory and pruritic skin disease with characteristic clinical features
• IgE abs to environmental allergens

Ag that favors development of hypersensitivity

• house dust mites - most common
• pollens
• molds
• storage mites
• epithelial cells

• defective epidermal barrier function -> exposure and absorption of allergens + water loss
• usually due to abnormal lamellar bodies

• epidermal lipids (esp in stratum corneum)
• ceramides
• cholesterol
• fatty acids
• sphingosine

• defective cutaneous barrier
• -> naive Langerhans cell (LC) processing of allergen
• -> LC migrates to LN
• -> naive T helper cell (Th0) presentation ->
• activate Th2 cell
• -> production of cytokines IL4, IL13
• -> cytokines stimulate B cell production of AS IgE
• -> AS IgE + Th2 cells migrate to dermis
• -> cycle of itch and inflammation
• -> ->
• re-exposure of allergen
• -> LC bound to AS IgE bind allergen and migrate to dermis
• -> present allergen to TH2
• -> cytokines like IL31 released
• -> activate sensory neurons
• -> pruritus

• pruritus and inflammation
• -> stratum corneum thickening
• -> worsened barrier function
• -> increased allergen penetration

Goldens, labs, WH fox terrier, dalmation, westie, small terriers, weimaraner, irish setter, shar peis, spaniels

• 1.5-3 years old
• can be 6mo-6yrs

insidious and gradual

will often start at a certain season, then progress to being year round

face, paws, distal extremities, ears, ventrum and especially caudal carpi

self trauma -> excoriation, erythema, alopecia, lichenification, hyperpigmentation, secondary infx at site predilections

• Staph pseudintermedius
• Malassezia pachydermatis

• systemic: corticosteroids (pred, temaril-P), EFAs, cyclosporine
• topical: corticosteroids (triamcinolone spray), EFA shampoo and spray, oatmeal, tacrolimus
• tx secondary infx

• They have greater affinity for keratinocytes of atopic dogs
• -> hypersensitivity to secondary pathogen
• -> increased pruritus
• -> CS e.g. collarettes, papules, pustules

• waxy brown exudate on proximal claws
• interdigital erythema

• must have 5 or more:
• -age of onset <3 years
• -mostly indoor dog
• -front feet affected
• -inner pinna affected (not margins)
• -dorso lumbar region unaffected (FAD)
• -chronic or recurrent Malassezia infx
• -responds to corticosteroid therapy
• -pruritus before skin lesions at onset

• 85% sensitivity
• 79% specificity

• face, neck and head pruritus
• miliary dermatitis
• -eosinophilic granuloma complex
• -over grooming alopecia

• signalment
• eliminate food allergy, FAD
• allergy testing (ELISA or intradermal)

• considered gold standard
• can customize allergens

• must have corresponding CS to be meaningful
• many false + and -
• can't be on anti-histamines or steroids
• chronic skin changes interfere
• need sedation or GA -> day hospitalization
• subjective results (and no standard)
• need experience

house dust mites, house dust, grasses

measurement of serum AS IgE with standardized results

• results are standardized
• no sedation, GA or hospitalization
• can run if there are chronic skin changes
• results less affected by anti-histamines and steroids

• the Ags aren't as pure
• can't customize Ags
• more false + (maybe)

• hyposensitization to specific allergens
• takes 4-6mo of weekly shots for improvement in 70% of cases

• Th2 -> Th1 cytokine profile switch
• IgE -> IgG switch
• Induce T cell tolerance by generation of allergen specific Treg cells -> decreased Th1 & Th2 cytokine response to allergen
• decrease APCs, T & B cells & effector cells

• decreased production of pro-inflammatory cytokines
• decreased T cell activation
• decreased eosinophilic function
• decreased mast cell degranulation
• decreased APCs in skin
• decreased vascular permeability (-> decreased effector cells)
• decreased LT and PgI (-> decreased arachidonic acid cascade)

• systemic: corticosteroids (pred, triamcinolone), EFAs, cyclosporine
• topical: corticosteroids (triamcinolone spray), EFA shampoo and spray, oatmeal, tacrolimus
• tx secondary infx

15 x lbs = mg pred / year

urine culture

ketoconazole, reduces dose by 50%

• calcineuron inhibitor blocks IL2
• decrease T cell activation
• decrease cytokines
• decrease function of effector cells

• blocks histamine receptors on blood vessels
• prevents erythema, vasodilation and swelling due to histamine

• not very effective
• other inflammatory mediators besides histamine

• improve barrier function
• reduces trans-epidermal water loss
• omega 3s compete with arachidonic acid, which reduces breakdown to pro-inflammatory mediators

• phytosphingosine (improves barrier function)
• and
• hinokitiol (plant metal chelator = anti-infective)

• same diet last 2+ years
• acute onset
• not seasonal
• +/- response to glucocorticoids

• young or old (middle aged tends to be AD)
• Goldens, terriers, GSD

• generalized pruritus
• pododermatitis
• bilateral otitis externa (>80% at presentation)
• -only CS in 20% cases
• scaling
• papules
• erythema

• pruritus and alopecia of neck and face
• papules
• miliary dermatitis
• eosinophilic granuloma complex

• maybe, maybe not
• V, increased pooping

• elimination diet trial 8-12 weeks
• rechallenge with old food
• should see CS return within 2 weeks

beef, dairy, chicken, lamb, corn, soy

fish, dairy, beef, lamb

• poorly haired regions
• interdigital, axilla, inguinal, muzzle, pinnae, perineal

allergic and irritant (more common)

• allergic requires sensitization
• irritant dermatitis happens on first exposure to allergen

• 5-25% of dogs have AD and CAFR
• 10-50% of dogs have FAD and AD
• AD predisposes dogs to have FAD

• Staph pseudintermedius - most common
• Staph schleiferi
• Staph aureus
• Proteus
• Pseudomonas
• E. coli

• less efficient stratum corneum allows bacterial invasion
• lack of ostial plug in entrance of hair follicle

more in cats, less in dogs

humans and horses, not dogs

nares and perianal

• pruritus
• inflammation
• disorders of cornification
• diseases of the hair follicle
• endocrinopathy
• poor grooming
• immunological defects

• acute moist dermatitis aka hotspot aka pyotraumatic deramtitis
• intertrigo (skin fold pyoderma)
• muco-cutaneous pyoderma

• impetigo
• superficial folliculitis
• superficial spreading pyoderma

• deep folliculitis
• deep furunculitis
• cellulitis
• deep pyoderma aka muzzle folliculitis aka canine acne

clip, no need for abx initially

• effect of temperature, pH, frictional microtrauma
• obesity can create skin folds

• a non-follicular subcorneal pustule
• often seen in less haired areas
• seen in puppies

follicular pustule

hemorrhagic crusts

• Look for underlying cause
• Systemic abx
• Abx shampoo

• deep infx
• immunodeficiency

• Resistance to penicillin, ampicillin, amoxicillin, sulfonamides
• -staphs have a beta lactamase enzyme
• More resistant bacteria in deep pyodermas

prior administration of abx

• cephalosporins
• lincomycin
• amoxicillin / clavulanate

• fluoroquinolones
• -marbofloxacin
• -enrofloxacin
• -ciprofloxacin

• use abx for 4 weeks
• monitor lesions and pruritus

• lesions are not improving
• abx in last 6-12mo

• TMs maybe
• doxycycline
• chloramphenicol
• amikacin

aplastic anemia when taken by humans

renal monitoring

• chlorhexidine - best choice
• benzoyl peroxide
• BP and sulfur
• ethyl lactate
• triclosan
• Give 2x a week with 10-15 min contact time

lipid dependent, humans only

• lipophilic (not lipid dependent) non-mycelial yeast
• found on animals
• reproduces by unipolar budding
• peanut shaped

• skin
• ear canal
• anal sacs
• vagina
• rectum

• 5+ Malassezia whole slide for skin cytology is significant
• Slightly more expected for ear cytology

• underlying host disease -> microclimate and defense changes
• barrier disruption (e.g. moisture accumulation)
• excess sebum or cerumen production
• defect in innate immunity (e.g. antimicrobial peptides, CMI, IgA)
• enzymes (lipases, proteases, zymosan)
• hypersensitivity?

• IgE (type 1) Malassezia hypersenstitivity
• type 1 and 4 seborrheic dermatitis

• AD
• cornification disorders
• chronic inflammation
• previous abx or steroids
• breed predilection

• Westie, Basset, Springer, GSD
• -Basset normally has intense colonization with no lesions unless becomes immunosuppressed

Devon Rex, Sphinx

• paraneoplastic skin disease (paraneoplastic alopecia, feline thymoma-associated)
• erythema multiforme
• FeLV
• FIV
• DM
• Neoplasia

generalized inflammatory skin disease, rapid onset, odor, pruritus, rapid response, no recurrence (rare)

associated with chronic, inflammatory skin disease, odor, pruritus

sharply demarcated margins

• Ventral neck
• Ventral abdomen, axilla
• Face, ears (pinna)
• Feet, forelegs
• Any skin folds
• Claw beds

• culture
• biopsy
• cytology

• tx the underlying disease
• systemic antifungals (ketoconazole, fluconazole, itraconazole, terbinafine)
• topicals (twice weekly shampoo or wipes with miconazole, ketoconazole, >2.5% chlorhexidine, 2.5% acetic acid, 2% boric acid)

uncontrolled recurrent malassezia infx

azole given on three consecutive days, try to reduce to twice weekly

only from dam -> puppies

hair follicles

• Demodex canis: most common
• D. injai: large bodied, in hair follicle and sebaceous glands
• D. cornei: Short-bodied stratum corneum, a sub-species of D. canis

• localized: <5 regions on body affected, or a paw affected
• generalized: 5 or more regions affected

• juvenile: <2 years old, average <1 year old
• adult: >2 years old, but average is >7 years old

• self limiting
• can add on mupirocin to avoid secondary infx

• Defective immune response: demodex specific
• T cell dysfunction: maybe
• Hereditary: predisposed
• Sex hormones: females in estrus or pregnancy

• spay if intact
• ivermectin PO (in ice cream)
• milbemycin
• moxidectin
• amitraz dip after clipping hair coat and bathing in antibacterial shampoo
• tx secondary pyoderma (cephalosporins, lincomycin, fluoroquinolones, clindamycin)*
• must monitor with deep skin scrapings once monthly*
• *must tx until 1mo after 2 negative skin scrapings done 1 mo apart*

• deep skin scraping
• hair pluck
• cytology of pustules (might see mites)
• biopsy (chronically inflammed and thickened lesions)
• minimum database for underlying diseases

• immunosuppressive corticosteroids
• hypothyroidism (beware sick euthyroid)
• hyperadrenocorticism
• Leishmania
• neoplasia
• idiopathic (25%)

• spay if intact
• ivermectin PO (in ice cream)
• milbemycin
• moxidectin
• amitraz dip after clipping hair coat and bathing in antibacterial shampoo
• tx secondary pyoderma (cephalosporins, lincomycin, fluoroquinolones, clindamycin)
• *must monitor with deep skin scrapings once monthly*
• *must tx until 1mo after 2 negative skin scrapings done 1 mo apart*

lethargy, anorexia, mydriasis, edematous wheals

ketoconazole

Collie, Shetland Sheepdog, Old English Sheepdog, English Shepherd, Australian Shepherd, McNab, Longhaired Whippet, Silken Windhound

Stupor, ataxia, trembling, transient vomiting (rare)

• diazepam
• barbituates

• 1ml of 12.5% amitraz concentrate in 30 ml mineral oil q24hrs
• -must have owners wear gloves

lethargy, hypoglycemia, hyperglycemia, V

give yohimbine or atipamazole

Need lifelong miticidal txt, but try to drop dose over time

• Demodex cati (hair follicles)
• Demodex gatoi (stratum corneum)

• DM
• FeLV
• FIV
• hyperadrenocorticism

• alopecia
• otitis externa

D. gatoi is contagious

• D. cati - deep skin scraping
• D. gatoi - superficial skin scraping (esp of other cats in household)

• moxidectin applied weekly
• lime sulfur if D. gatoi
• amitraz
• milbemycin

• highly contagious
• *intensely pruritic*

Sarcoptes scabiei canis

• Direct transmission from infected animals (mites are obligate parasites, so fomite transmission is less likely)
• Female burrows and lays eggs
• Complex hypersensitivity rxn

• Yes, but humans are a dead-end host
• Can have continuing signs of pruritus if constantly re-infested by dog with scabies

• *Must tx every animal (including humans) in the contact*
• selamectin (adulticide, requires 2 txt/month for 2 months)
• ivermectin (same as selamectin)
• 2% lime sulfur (2x / week for a month)
• milbemycin oxime
• topical moxidectin

young (exposed to more infested environments like shelters, breeders, pet stores)

• *intense pruritus*
• dramatic erythematous maculopapular eruption (red rash) with crusts and alopecia on the ventrum, around the pinna and lateral elbows

• Hx: contagion, pruritus and zoonosis
• Skin scraping (50% sensitive)
• Response to txt

Notoedres cati

• highly contagious
• *intensely pruritic*

• direct transmission from infested cat (obligate parasite)
• Female burrows, lays eggs
• Complex hypersensitivity rxn

Rarely, and humans are a dead end host

crusting, scaling, lichenification, erythema, alopecia, excoriation on the head and pinna, maybe see on the feet too

• Hx: pruritus, contagion, zoonosis
• PE
• skin scraping (>50% sensitivity)
• Response to txt

• selamectin
• ivermectin
• 2% lime sulfur
• amitraz
• milbemycin oxime
• *treat all animals (including humans) in contact

• Contagious
• Variably pruritic

• Areas with poor flea control (prevented by Frontline and Advantage multi)
• On rabbits

• Directed transmission from infested animals (obligate parasite)
• Stay on epidermal surface (no burrowing)
• Hypersensitivity rxn

Likely under-dx

• Scaling and crusting
• Variable pruritus
• See on the dorsum, but varies with species
• -dog have dorsal scale
• -cats have miliary dermatitis
• -rabbits have crusts on head, neck and ears plus scale on the dorsum

• Hx: contagion, pruritus, zoonosis
• PE
• skin scraping

• selamectin
• ivermectin
• 2% lime sulfur
• amitraz
• milbemycin oxime
• *must tx all in contact animals (including humans)*
• Wash and dry the bedding (heat kills them)

• Linognathus setosus (Anoplura sucking louse)
• Trichodectes canis (Mallophaga biting louse)

• Areas of poor flea control
• Flea adulticides = lice adulticides

Felicola subrostratuas (Mallophagia biting louse)

• selamectin
• *must tx all animals in the house of the same species (lice are very species specific)

Genetic program of keratinocytes in the basal cell layer to mature, die, & produce the stratum corneum

Keratinization + formation of lipid interstitium holding the dead keratinocytes together

excess stratum corneum

scale + blood, pus, microbes, cells

corneocytes plus filaggrin, ceramides, other lipids

Production of keratohyaline granules (keratin, pro-filaggrin) and lamellar granules (ceramindes, other lipids)

keratinocytes begin to ‘flatten’; cytoplasmic attachments via desmosomes

Keratinocytes undergo mitosis several times before becoming nonmitotic and progressing ‘upwards’

• genetic (aka breed-related aka idiopathic)
• congenital
• nutritional

Parasitic, endocrine, infectious, neoplastic...

Secondary

primary keratinization / cornification defect (PKD)

cocker spaniel, irish setter

• scale and crust on pinna and trunk
• ceruminous otitis externa
• rancid odor
• variable pruritus
• secondary bacterial or yeast infx

• Shampoos with sulfur or salicylic acid
• treat the secondary infx
• retinoids, VitA
• maybe corticosteroids, cyclosporine

Rare, congenital, hereditary group of diseases that causes excessive scaling

Breeds: Norfolk terriers (autosomal recessive disorder of keratin 10), Golden Retrievers, Cavalier King Charles spaniels, American Bulldogs

skin biopsy

Can't, so neuter to prevent

• Kerry blue terriers and Dogue de Bordeaux: excessive foot pad fronding
• Spaniels and brachycephalics: nasal planum
• Labs: parakeratosis of nasal planum

Vizla, Akita, Standard Poodle, Lhasa Apso

idiopathic granulomatous destruction of sebaceous glands

• scaling and alopecia
• secondary infx

• signalment: predisposed breeds
• CS: alopecia and scale
• skin scraping: follicular casting
• skin biopsy: shows absence of hair follicles - need good pathologist

• VitA - expect improvement in 6weeks
• *will need to monitor tear production with STT*
• cyclosporine can help

• syndrome I: Huskies and white GSDs get crusting and scaling of muco-cutaneous junctions, elbows and footpads
• syndrome II: any breed fed excessive Ca or plant protein. See crusting plaques, fissured foot pads, fever and malaise

• syndrome I: defect in  Zn absorption
• syndrome II: excessive Ca or plant protein in diet

• Hx: breed predisposition
• histo: follicular and epidermal parakeratotic hyperkeratosis

• syndrome I: elemental Zn and OVH
• syndrome II: balance diet, can add Zn supplementation to get faster resolution

• Thickened, slightly depressed hyperpigmented erythematous, alopecic lesion
• Left front leg
• Large breeds predisposed
• Young - middle aged dogs

• behavior
• deep pyoderma
• allergy (AD)
• Rare: neoplasia, orthopedic devices, osteomyelitis, other infections

lameness

• Hx
• CS
• rads
• biopsy
• culture (both deep and superficial)

• Antibiotics
• Psychoactive medications (Amitryptiline, Clomipramine)
• Narcotic antagonists (Naltrexone, Hydroxycodone)
• Fluocinolone acetonide in DMSO base (SynoticTM)
• Flunixin meglumine (BanamineTM)
• Capsaicin cream
• Heet ® - OTC, contains capsaicin

Actinomyces

summer and fall

• Remove if possible
• Abx (empircial or C&S)

• Dermatomyositis
• Ischemic dermatitis due to vaccines or other medications
• Idiopathic ischemic dermatoses

• Unknown etiology
• Collies, shelties = autosomal dominant transmission
• Early onset, < 6 months

• Alopecia, depigmentation, erythema, scarring
• Myositis (if present) affects muscles of mastication and limb girdles
• Severe cases = megaesophagus

Inner pinna affected but no otitis externa

• Hx: breed
• Skin histopathology: ischemic dermatosis
• Muscle histopathology: myositis

• Pentoxifylline (methylxanthine family)
• Tacrolimus
• Cyclosporine

Vomiting, hyperexcitability

• Drug
• Idiopathic
• Rabies vaccine frequently implicated or suspected
• -vx rxns may occur 6 months later

• Idiopathic
• Dogs < 3 months old (rarely, adults)
• Breed: any, but commonly retrievers, dachshunds, and Brittany spaniels

• Suggestive of infection, but NO organism identified (sterile pyogranuloma)
• Mandibular lymphadenopathy (may fistulate)
• Edema, pustules, papules, or crusts around the eyes, mouth, muzzle, ears
• Lethargy, fever and anorexia
• Sterile arthritis

• Pred (because it's sterile) + abx (cephalosporin, but it's not infectious...more CYA)
• Dogs feel and look better within 24 hours of txt

Clinical sx, aspirates if needed

• Approximately 10% of dogs will relapse after the month of treatment is stopped
• Older dogs may require longer Rx, sometimes with other drugs (azathioprine)
• Cyclosporine has been used in a few dogs with good success ($$$)

• Inflammation of the external ear canal epithelium
• + / - pinnal dermatitis

• Vertical and horizontal canals
• Modified squamous epithelium
• Numerous large sebaceous & ceruminous glands
• Hair follicles

• White, oval shaped membrane that relays vibrations to ossicles
• Has two parts: pars flacida (dorsal, vascular) and pars densa (ventral)
• Divides external ear from the middle ear
• TM rupture -> otitis media

• Dogs: 5–8 years of age from allergic dermatitis
• Cats: 1–2 years of age from ear mites

• Alter microenvironment of the ear canal
• Breed ear conformation
• High humidity in ear canal
• Obstructive ear disease
• Treatment errors

• Pendulous pinnae
• Hairs within ear canal (hirsutism)
• Narrow canal conformation
• Increased # of apocrine glands

• Poor anatomical ventilation
• Frequent swimming / bathing
• Obstruction of ear canal (tumors or polyps, inflammation -> epithelial swelling)

• Mechanical trauma (plucking hair, use Q-tips that push debris towards TMb)
• Irritant topical products
• Improper antibiotic usage

• Allergy (AD, CAFR)
• Contact allergy
• Parasites
• Foreign bodies
• PKD
• Neoplasia
• Immune–mediated diseases

neomycin

• Otodectes cynotis (50% in cats, 10% in dogs)
• Demodex canis
• Otobius megnini

• Ceruminous gland ademomas
• Adenocarcinomas
• SCC

• PF
• Systemic lupus erythematosis
• Erythema multiforme
• Ischemic dermatopathy
• Juvenile cellulitis

• Bacterial organisms
• Fungal organisms
• Otitis media
• Chronic pathologic change (irreversible)

• Staph pseudintermedius
• Strep sp.
• Pseudomonas sp.
• Proteus sp.
• *Often have resistance*

• Malassezia (but also normal ear flora)
• Candida sp. (rare)
• Aspergillus (rare)
• Dermatophytes & systemic fungal mycoses (cause pinnal dermatitis, not directly otitis externa)

With otitis externa EVEN if TMb intact

• Systemic abx
• +/- surgery (bulla osteotomy)

• CS
• Imaging (CT)

• Epithelial hyperplasia & glandular hyperplasia
• Calcification of auditory canal
• Fibrosis of dermis & subcutis

• Hx + PE
• Otoscopic examination
• Cytology
• Culture & sensitivity
• Imaging studies
• Myringotomy (incise TMb)
• Biopsy

• otitis media
• cytology with lots of rods
• poorly responsive cases

• Make a specific diagnosis & identify all factors involved
• Use ear cleaner prior to treating with appropriate topical +/- systemic therapies
• Instruct owners how to clean ears & apply medications
• Re-evaluate frequently

• Modified cleaning / drying solutions : antimicrobial properties & mild ceruminolytic agents
• Examples: Epi-Otic® , Oti-clens®, Chlorhexi Derm®, Malacetic Otic® Douxo micellar solution®
• Potent ceruminolytic agents so always flush with saline after use

• topical antibiotic, glucocorticoid & an anti-fungal
• E.g. Tresaderm®, Otomax®

• Antipruritic + anti-inflammatory
• Decrease sebaceous & apocrine gland secretion
• Often in combination products
• Used as sole topical agent in allergic or ceruminous otitis

• Antibiotics: cases of otitis media or severe inflammation
• Glucocorticoids: short course to diminish inflammation
• Anti-fungals: refractory otitis externa or otitis media due to yeast