Dermatology

• tests SUPPORT dx, don't make it!!  A skin scrape missed demodex 75% of the time
• HISTORY is your number one tool - skin reflects the systemic environment

feel for them with your fingers.  Looking only shows superficial

• primary created from disease, good for testing.
• secondary are ruptured, usually from (self) trauma.  No longer good for testing

• macuole or patch
• papule or plaque
• nodule or tumor
• pustule
• vesicle or bulla
• wheal
• cyst

• area of altered pigmentation.  A macule is <1cm, a patch is >1cm
• primary lesion

• solid elevated mass <1cm in diameter (larger is nodule)
• squeeze for cytology
• staphylococcal, parasitic, dermatophytic
• primary lesion

• solid elevated mass >1cm (smaller is papule)
• FNA for testing (firm)
• staphylococcal, fungal, neoplastic, sterile disorders
• primary lesion

• none, really, until diagnostics.  Size difference is unclear.
• primary lesion

Histopathology!  Cytology disrupts normal architecture, so histo needed for staging.

• flat-topped solid elevated mass
• hives pit with pressure (so different)
• can't FNA (but can palpate), so have to biopsy.
• primary lesion

• flat-topped but boggy mass.  Pits with pressure (plaques are solid).  Steep walled.  
• Hives = type 1 hypersensitivity (zebra urticaria!)
• primary lesion

• fluid-filled lesion filled with pus
• infection = degeneratie neutrophils.  Non-degenerate = sterile.  Erythematous = inflamed
• knock the top off and sample, must be intact!
• staphylococcal disorders, sterile disorders (pemphigus)
• primary lesion

• fluid-filled lesion not filled with pus, <1cm
• have to biopsy skin in a hemorrhagic blister/vesicle, because blood won't tell you anything (coag?  Hemangiosarc?)
• sterile disorders, vascular disorders, neoplastic conditions
• primary lesion

• fluid-filled lesion not filled with pus (blister) >1cm
• have to biopsy skin in a hemorrhagic blister/vesicle, because blood won't tell you anything (coag?  Hemangiosarc?)
• primary lesion

• lots of different times, congenital or acquired.  
• Diagnose via examination of cyst wall.  
• Lesion full of stuff (NOT sebaceous, can be full of anything (else), sweat etc.). Can look like pustules (miliary), hair growing out (dermoid)
• fluid drains right out
• primary lesion

• alopecia
• scale
• crust
• comedo
• hair cast
• pigmentary abnormality

less than normal numbers of hairs

• complete hair loss
• can be just one kind, like primary hairs, or a color

increased numbers of hairs

• accumulation of exfoliated epithelial cells
• (sunburn or low humidity.  Weight-reducing diet so no fat?  Skin needs fat)

dried liquid vs cells on skin's surface.  Sweat or serum ooze to the surface and dry

• dilated hair follicle filled with keratin
• open is a blackhead, closed is miliary pattern

• disorder of follicular keratinization
• hair follicle filled with keratinogenous plug extending above skin's surface, hair comes out in clumps, hair pasted together

• epidermal collarette
• excoriation
• erosion or ulcer
• fissure
• scar
• lichenification
• callus

• "footprint" of a pustule or a vesicle
• poor lesion to sample (secondary)
• no diagnosis from ruptured!  Find a primary lesion to sample!!

• self-induced lesions caused by scratching, chewing, licking, licking, rubbing, rolling
• secondary lesions

• loss of epidermal tissue, most shallow, above BMZ
• secondary lesion

• loss of epidermal tissue and dermal tissue, below BMZ (will scar, deepest)
• secondary tissue

• loss of epidermal and dermal tissue, linear ulcer
• secondary lesion

• healed ulcer
• secondary lesion
• 10x more likely to get SCC with sun

• sign of chronicity
• lesions often hyperpigmented (tree bark)
• secondary lesion

• found over bony prominences
• protects underlying tissues (pressure point proliferation)
• secondary lesion

systemic disease

out of sight, just a BUMP

• pluck 10-15 hairs, mount in mineral oil
• Should be bulb, shaft, tapered tip with cuticle, cortex, medulla.  
• Normal response is mix of anagen and telogen hairs, mix of primary and secondary hairs in dogs

• used to collect samples (cytology) from solid or deep lesions
• suction vs trocar

• used to sample fluid filled lesions
• clinical microhematocrit tubes and centrifuge used
• avoid bloody or viscid fluids

• differentiates vascular dilitation from vascular leakage
• vascular dilatation blanches with pressure
• vascular leakage (coagulopathy or vasculopathy) does not blanch with pressure - indicates RBC OUTSIDE of vessels

• UV light
• microsporum canis only
• fluorescence due to triptophan metabolites
• many false positives and negatives

• modified Sabouraud's agar with pH indicator to detect dermatophytes
• protein metabolism to alkaline metabolites to red color change
• color change and colony growth occur simultaneously

• CYTOLOGY FIRST
• indicated when organism can't be ID'd, rational tx are ineffective or tx vary widely in expense
• culture INTACT lesions, use reliable lab

• underused! Inflammatory must be examined by veterinary dermatopathologist
• incisional or excisional techniques
• contraindicated in deep or fragile lesions
• could use punch or blade technique

wheal (zebra urticaria), hives

wheal

vesicle

ulcer

tumor

• sucking louse, anoplura
• operculated eggs stuck to hairs, grossly visible
• more likely to cause hypersensitivity and be killed by systemic drugs

scar

scale

pustule

lichenoid plaques

plaque

papule

papule

• otodectes
• non-burrowing psoroptid ear mite, also on rest of body.  
• usually puppies and kittens
• NO HOST SPECIFICITY

open comedo

nodule

miliary comedo

macule, patch

lichenification

lice and eggs

hair casts

hair casts

erosion, ulcer

epidermal collarette

dermatoid cyst

• demodex gatoi, feline demodicosis
• fecal float or tape cytology
• CONTAGIOUS, asymptomatic carriers
• variable signs
• surface parasite, lives on surface of skin, variable symptoms.  
• Itchy!
• usually ventral because contagious

• demodex cati, feline demodicosis
• immunosuppression (kittens or FeLV, FIP, lymphoma etc.)
• non-itchy alopecia = something wrong with follicle!  Demodex or dermatophytosis
• follicular or otic
• DEEP scrape, cure difficult. 
• Don't need to tx in kittens

cyst

crust

chorioptes

• cheyletiella, 3 kinds (cheyletiella yasguri, C. blakei, C parasitivorax)
• no host specificity (but some host preference)
• SURFACE parasite with non-operculated eggs cemented to hairs
• Hurts when bites!!!
• longest off-host life (10+ days)
• Clinical signs: variable.  none to dorsal seborrhea, +/- pruritis. Variable clinical signs, often none or dorsally oriented walking dandruff (seborrhea +/- pruritus, scabies-like pruritus)STARTS AT TOPLINE AND WORKS DOWN
• will bite O through clothes 
• Dx: fecal float, tape, flea comb, treatment test
• don't suck blood!  So blood-borne drugs won't help (bravecto)

• chewing louse, mallophaga
• operculated eggs stuck to hairs, grossly visible (can't see chyletiella)
• less likely to cause hypersensitivity than sucking.
• Can't use systemic as well.

callus

bulla

broken hairs

• centered on hair follicles
• pathologic, progressive: invasion of follicle wall, progression into lumen, rupture of pustule or follicle wall.  Infectious most common reason.  
• Most things in the hair follicle will be neutrophilic

• nonfollicular bacterial pustular disease (non-haired or injured skin, little inflammation).  Usu staph (puppy pyoderma)
• uncommon in dogs, rare in cats.  
• puppies 0-6months, asymptomatic otherwise.  Otherwise immunosuppressed.

• pre-existing reason needed for infection (immune deficiency, metabolic disorder, skin disease)
• common species like staph pseud, aureus. Resistance a problem.

• secondary to nasal trauma (pruritic disorder vs rodent hole burrowing, etc)
• slowly progressive
• painful or pruritic
• heals with scarring

• "canine acne"
• initiated by trauma to chin
• initially sterile, heals with scarring

• commonly short-coated breeds, follows bathing by 12-24h
• contaminated shampoos, water or bathing utensils
• painful, systemic signs of illness
• cytology mandatory

• chronic recurrent condition
• GSD commonly affected
• infection starts at mucocutaneous junction (lips, nares, eyelids)

• mimics acute moist dermatitis ("hot spot")
• sudden onset of self trauma to "normal" skin
• painful
• distinguish from "hot spot" by palpation, presence of satellite lesions

• follows behavioral issue, skin trauma, deep seated disease
• hairs imbedded deeply, heals with scarring

• triggered by conformation of foot, pruritic pedal disorders, environmental factors
• progressive disorder
• heals with scarring

• uncommon
• mimics noninfectious conditions (miliary dermatitis)
• secondary to pruritic skin disorders, chronic glucocorticoid use

• uncommon
• follow skin damage or overzealous O treatments
• Staph in horses is itchy--which came first, the staph or the trauma?

• streptothricosis, rain scald, rain rot, lumpy wool, strawberry foot rot, mycotic dermatitis, aphis
• activated by water (pruny skin, stratum corneum peels off, enough damage to cause top line dz, exudative dermatitis
• peel off crust to tx, send in for dx.  Sedate to peel, painful!

acral lick folliculitis

acute moist folliculitis, mimics hot spot

dermatophilosis

impetigo

impetigo (skin was previously broken)

mucocutaneous staphylococcal pyoderma

muzzle furunculosis

nasal furunculosis

pedal furunculosis

staphylococcal folliculitis

staphylococcal folliculitis

• of or relating to ear or sense of hearing
• AD = right ear
• AS = left ear
• AU = both ears

• inflammation of ear, sterile or with infection
• otitis externa (pinna to tympanic)
• otitis media (tissues comprising or contained within middle ear)

yellow waxy substance comprised of secretions from ceruminous and sebaceous glands comingled with desquamated keratinocytes (ear wax)

• increase in # of glandular cells, usu incited by inflammation
• 

abnormal narrowing of tubular structure

excessive fibrous CT formation in a repairative or reactive process (long term)

• calcium deposition within cells resulting in phosphate accumulation and microcrystal formation
• response to tissue damage

• intertragic incisure
• 

• pars flaccida: vascular, can bulge from air pressure/respiration
• pars tensa: translucent
• 

• primary: create disease in normal ear
• secondary: create disease in abnormal ear
• predisposing factor: prior to development of ear disease
• perpetuating factor: result of otic inflammation

• hypersensitivity diseases: atopic dermatitis, food, adverse drug rx, contact most common from medications or vehicles, 90% or greater
• parasites: otodectes cynos most, mites, tick and flies
• foreign bodies: inflammation blocks canal, predisposes
• keratinization disorders: chronic ceruminous otitis (cockers make too much), idiopathic seborrhea (rest of body too), hypothyroidism
• immune-mediated diseases

• hypersensitivity otitis externa
• contact most common, meds or vehicles

otodectes cynos, otitis externa

• otodectes cynos, otitis externa
• non-burrowing psoroptid ear mite, also on rest of body.  
• usually puppies and kittens
• NO HOST SPECIFICITY

demodectic mange otitis externa, can see demodex mites on cytology, should also see on rest of body

• in an ABNORMAL CANAL
• bacteria: staph pseudintermedius most common, pseudomonas, proteus, e coli, klebsiella.  Inflammation is the difference between infection and overgrowth
• yeast: malassezia pachydermatis, candida
• topical acquired irritant rxns

bacterial otitis, SECONDARY to something else!!!

yeast otitis, SECONDARY to something else!!!

• won't CAUSE but will exacerbate
• conformation: floppy decrease circulation, stenotic breeds increase glandular secretions, humidity (don't pluck!)
• excessive moisture: increased risk with swimming, water may be contaminated
• obstructive ear disease: nasopharyngeal polyps, ceruminous cystomatosis, ceruminous gland neoplasia
• primary otitis media:

nasopharyngeal polyp, obstructive disease PREDISPOSING young cats to otitis externa

• ceruminous cystomatosis
• obstructive disease usually throughout ear canal, debris trapped, PREDISPOSES to otitis externa

• hole in tympanic membrane, suck out fluid and culture
• for otitis media.  Culture and flush.

• only in some cases: parasites, severe or refractory otitis externa, marked proliferative changes, otitis media, O can't administer, topical adverse rxns
• tx must be use AT LEAST 1 WEEK after resolution (cytological)

• removes vertical canal only, only if dz is ONLY there.  For non-responsive otitis externa, permanent exposure of horizontal canal.  Improves drainage, reduces humidity.  50% effective. 
• 

• address predisposing, primary, secondary, perpetuating causes
• cytology initially and at rechecks
• appropriate treatment, dose and time
• follow up!!

• accumulation of blood within pinna, secondary to head-shaking or trauma (often secondary to otitis externa)
• cartilate of pinna sheared, blood accumulates intracondrally.

• convex.  
• concave side less vascular

• teat cannula
• suction drain
• multiple perforations with skin punch or laser (VERTICAL)
• multiple aspirations
• plastic rivets or BUTTONS
• incision with through-and-through sutures
• TREAT OTITIS!!!

• anesthesia
• treat otitis externa
• clip and prep pinna
• linear incision on concave side, entire span of hematoma
• remove fibrinous material (better cosmetic result)
• Full thickness sutures PARALLEL to long axis (preserve blood supply)
• Suture through non-adherent pad on convex side of ear, through-and-through. 
• knots over non-adherent pad on convex side, snug to compress pinna (so can find knots in 3 weeks)
• pendulous pinna wrapped over head to prevent shaking, remove sutures in 3 weeks, keep treating otitis.

• can do bilaterally.  Clip and prep, clean canal, measure depth of vertical. 
• Skin incision 50% longer than vertical canal, parallel incision lateral to tragus, connect with "U", dissect skin flap up to tragus
• incise cartilage of vertical canal between lateral and cranial wall, lateral and caudal wall with mayo scissors, fold down (parallel, don't cut off!)
• suture skin flap down, leave cartilage down as drip track.
• wrap and analgesia for 3-5 days, sutures removed in 10-14.  Tx otitis.

• cats 1-3 years old
• hx of URI virus when young
• polyps originate in middle ear, expands nasopharyngeally or aurally
• may see Horner's, vestibular signs
• occasionally bilateral or unilateral mixed

• 1-3yo cats with hx of URI virus when young, polyp in middle ear grows laterally
• chronic otitis externa, refractory to medical mgmt.
• extracted through ear, 40% recur if you don't get it all so LOOK with otoscope (only 13% recurrence)

• 1-3yo cats with hx of URI virus when young, polyp in middle ear grows medially
• UR signs like nasal d/c, sneezing, stertor, dyspnea
• mid-point of soft palate, so compression and possible occlusion of nasopharynx
• extract through the mouth, 10-41% recurrence, lower with steroids (oral or aural)
• Possible transient Horner's, ventral bulla osteotomy for recurring

removal of feline aural polyp that is otoscope-guided with alligator forceps, so you can get it all (in the canal)

• removal of entire ear canal surgically
• remove vertical, horizontal and annular cartilages
• lateral bulla osteotomy - CAREFUL with facial nerve!
• T-shaped incision over lateral aspect of vertical canal. Encircle external canal, dissect off auricular muscles, dissect out branch of facial nerve, dissect annular cartilage from petrous temporal bone
• bone ronguer expands external auditory meatus for access, lateral bulla osteotomy with bone curette (VENTRAL portion only, avoid vestibular apparatus and cochlea)
• lavage with saline, close deep tissues then T in skin. 
• analgesics, head wrap, E collar, 3 weeks of abx based on culture.

• nonresponsive otitis externa with severe epithelial hyperplasia
• neoplasia of ear canal (ceruminous gland adenocarcinoma)
• revision of failed lateral ear canal resection

• 10% facial nerve paralysis
• <5% facial fistula (didn't get all the infection)
• <1% vestibular signs
• 100% hearing loss

• acute and severe
• therapy has significant side effects
• suspected neoplasia
• lesions appear unusual
• new lesions WHILE on therapy
• lesions don't respond to therapy

• TAKE 3-5!!!  If generalized.
• 6mm ideal, NO SMALLER than 4mm.
• Shoot for primary lesions first.

• a DERMATOPATHOLOGIST
• concise history (signalment, description/photos, location, clinical signs? duration)
• abx before biopsy if secondary infection suspected
• steroids STOPPED before biopsy
• fix in 10% formalin, and stick the SQ to cardboard or tongue depressor to prevent curling or rolling (don't need for full thickness when >6mm)

• DON'T scrub/prep
• DON'T clip too close
• DON'T squeeze the sample
• DON'T reuse biopsy punches
• DON'T use cautery on small samples
• DON'T ship over the weekend in winter (freezing)
• DON'T use a punch for deep or fragile lesions (wedge biopsy!)
• DON'T sample the center of an ulcer

• increased thickness of stratum corneum
• orthokeratotic: composed of completely cornified cells.  developmental, endocriopathies
• parakeratotic: retain nuclei in stratum corneum (incomplete cornification).  Ectoparasites, malassezia
• nondiagnostic, found in most chronic dermatitis

• increased thickness of noncornified epidermis due to increased NUMBER of cells. Can cause rete ridge (pegs projecting into dermis, only normal in pig).  Common in chronic inflammatory.
• regular: evenly thickened
• irregular: uneven, pointed rete ridges
• psoriasiform: evenly elongated rete ridges, clubbed and fused at base. Chronically traumatized skin lesions.
• papillated: digitate projections above skin surface
• pseudocarcinomatous: extremely irregular due to underlying dz with chronic ulcers

• apoptotic keratinocytes, seen in any hyperplastic epidermis
• cell shrinks, becomes denser, cytoplasm more eosinophilic, loses normal contacts, pyknosis or karyorrhexis.  
• aka Civatte are when in stratum basale, sunburn cells when caused by UV radiation

• intercellular edema (widening of intercellular spaces).  Severe forms vesicles within epidermis.
• no displacement of nucleus

• DISPLACED NUCLEUS so different than spongiosis.
• increased size and cytoplasmic pallor.  Severe causes reticular degeneration and intraepidermal vesicles.

• koilocytosis
• degeneration seen in epidermal cells
• swollen stippled cytoplasm without vacuolization, enlarged or condensed or multiple nuclei, loss of cohesion (acantholysis).

• intracellular edema only in stratum basale
• rarely can cause intrabasalar or subepidermal clefting
• uncommon

• loss of cohesion between epidermal cells, causes epidermal clefts, vesicles and bullae.
• free epidermal cells in vesicles are acantholytic keratinocytes

• intraepidermal and subepidermal cavities with inflammatory cells
• degenerate neutrophils: MO infection
• nondegenerate neutrophils: pemphigus
• eosinophils: ectoparasites, eosinophilic granuloma, eosinophilic folliculitis, pemphigus, malassezia
• Pautrier's microabscess: abnormal lymphoid cells, epitheliotropic lymphoma
• mononuclear cells: atopy, contact hypersensitivity

• hyalinization of collagen fibers
• lysis and loss of structure
• dystrophic mineralization
• atrophy
• dysplasia
• "flame figure" - altered collagen surrounded by eosinophils and granules in starburst pattern.

• melanin granules free within subepidermal and perifollicular dermis within dermal macrophages (melanophages)
• seen when stratum basale and basement membrane zone damage, esp hydropic degeneration.  (canine demodecosis)

• lots of amorphous, stringy, granular, basophilic material that separates, thins or replaces dermal collagen fibrils and surrounds vessels.  Small amounts normal.  
• Lots in Shar Pei, hypothyroid, acromegaly.  
• Eosinophilic dermatoses can have mucuin in epidermis and hair follicle outer root sheath

• affected by epidermal changes
• perifolliculitis (around), mural folliculitis (wall of follicle, lumen spared. 4 subtypes), luminal folliculitis (MOST COMMON, usu infectious) and furunculosis (follicular rupture, usu from lumenal) are degrees of follicular inflammation
• follicular atrophy is gradual involution and miniaturization
• examine follicles for stage of growth to help with dx.

• sebaceous glands: involved in suppurative and granulomatous inflammations, late stage can have no sebaceous glands left. Can atrophy or become hyperplastic, assess in regards to location.  
• Melanosis
• Epitrichial sweat gland

infiltration of cells between collagen bundles of the dermis, does not obscure anatomy of skin.

• dermoepidermal junction is obscured by hydropic degeneration, lichenoid cellular infiltrate or both.  
• Can see apoptotic bodies, satellite cell apoptosis with pigmentary incontinence seen.

• (wall, not lumen)
• interface mural
• infiltrative mural - lymphocytes and histiocytes
• necrotizing mural
• pustular mural

• inflammation of subcutis
• most cases sterile, idiopathic 
• dogs, cats, horses
• solitary or multiple
• commonly on trunk
• SQ nodule to fluctuant "cystic" lesion +/- draining tracts

• ringworm
• microsporum and trichophyton species (animals usually)
• 3 groups: geophilic (soil, like gypseum), zoophilic (adapted to animals, rarely in soil, canis, equinum, distortum, T equinum), anthropophilic (adapted to humans, not in soil, audouinii)
• M. canis, M gypseum, T. mentagrophytes most common in dogs and cats

• more in hot, humid
• transmission via contact with infected animals (cats), environment, fomites
• very young, very old, immunocompromised
• genetics (persian cats, yorkies, jack russels, pekinese)
• ARTHROSPORE is infective, survives in environment for 18 months
• infects disrupted parts of stratum corneum (ectoparasites, fleas, etc)
• invades ANAGEN hair follicle, arthrospores adhere to keratin and germinate in 6 hours.  Keratolytic enzymes penetrate cuticle and migrate toward hair bulb
• clinical lesions in 7-14d, enlarge for 6-8wks, spontaneous resolution in 12-14wks (telogen phase stops keratin production, inflammation)

• localized: face, pinna, paw, tail.  Usually less than 1 year old, +/- pruritus
• Tip: if it looks like ringworm, it's probably staphylococcal folliculitis

• from wild animals
• in adult dogs, from sticking heads into burrow
• T. mentagrophytes, M. persicolor

• rare in dogs and cats
• one digit or multiple digits on one paw get paronychia or onychodystrophy
• T. mentagrophytes (ringworm) in dogs

• nodular infection from furunculosis
• baggy, exudative, may have draining tracts
• usually in adults and solitary on face or distal limb.
• M gypseum or T mentagrophytes (ringworm)

• one or more annular areas of alopecia +/- scales
• more common on head, pinnae, paws, can get "stud tail" (dermatitis of dorsal tail)
• cats <1year
• +/- pruritus
• esp long-haired, persians
• GENERALIZED more common in cats than dogs
• TIP: if it looks like ringworm in a cat, it probably is
• widespread severe alopecia with little inflammation, pruritic miliary dermatitis, chin folliculitis (acne), generalized seborrheic-like eruptions, crusting over bridge of nose, pinnae and paronychia resembling pemphigus, dermatophytic pseudomycetoma (Persians)

• Trichophyton equinum most common
• <2 years old
• face, neck, dorsolateral thorax and girth, pruritus variable, pastern dermatitis (grease heel, wax and wane), lesions can by symmetric, rarely solitary, general disease rare. 
• COMMON - 9% of skin disease.  
• ddx: staph (most common, dermatophytes #3), dermatophilosis (#2), pemphigus, sterile eosinophilic folliculitis
• Everyone needs their own tack and brush!

• trichophyton verrucosum like goats
• <1year old, fall and winter in confined animals
• face, head, pinnae, neck, rump, tail, perineum.
• Crusted papules that become THICK grey crusts, pruritus rare.
• ddx: staphylococcal folliculitis, dermatophilosis, dermodecosis, stephanofilaria, sterile eosinophilic folliculitis, zinc-responsive dermatosis

• trichophyton verrucosum like cows
• face, head, pinnae, neck and legs
• <1 year
• pruritus rare

• Microsporum nanum
• face, pinnae, trunk
• brown to orange annular crusts, may be large
• alopecia and pruritus rare

• children, elderly, immunocompromised
• most come from cats
• usually microsporum canis
• horse to human infections rare

• history--exposure, pruritus
• PE--folliculitis
• wood's lamp: 50% fluoresce, so lots of false + and false -, needs to be warmed up
• scrapes and trichogram--40-70% positive
• fungal culture of hair/scale--MOST RELIABLE but can still have false + and -
• biopsy for kerion and pseudomycetomas

• dermatophyte test medium (DTM)
• sabouraud's dextrose agar containing cycloheximine, gentamicin and chloretetracycline
• pH indicator phenol red, should turn red ASAP once you see growth.  Dermatophytes use protein and alkaline metabolites turn media red.  Other fungi use carbs first, will turn red later
• Examine DAILY for 10 days.

• normal flora in dogs, cats.  Live in haired skin, ear canal and mucosal areas.  Colonize superficial epidermis. 
• Can cause hypersensitivity in dogs.  Other animals have some underlying comorbidity first (allergy, endocrinopathy, keratinization prob, corticosteroids, etc)
• predisposed: westies!  cockers!  
• presentation: moderate to severe PRURITUS, alopecia, excortiations (self-induced), erythema, seborrhea.  Chronic will cause lichenification, hyperpigmentation, hyperkeratosis
• interdigital, ventral neck, axillae, perineal, skin folds, paronychia (claw beds), ear canals (secondary otitis!!)

• Hx and PE, smear/impression/tape, culture (normal resident!), biopsy, response to therapy
• tx: address underlying cause, topicals for mild localized dz, systemic if generalized, chronic or super severe, or super deep (paronychia).  Tx until resolution + 1 week.  Not contagious

• circumscribed, solid lesions >1cm.  May be elevated or SQ.  
• Aka tumor?

a swelling part of the body.  Abnormal benign or malignant new growth of tissue.  Aka nodule?

circumscribed, elevated, solid, flat-topped.  SUPERFICIAL

benign focal malformation resembling a neoplasm in tissue of origin.  Grows at same rate as surrounding tissue.  Made of tissue elements usually found at that site, just growing disorganizedly.

• granulomatous to pyogranulomatous
• 1: infection - bacterial, fungal, protozoal, parasitic
• 2: foreign body - plant material, ruptured cyst or hair follicle
• 3: sterile idiopathic - immune mediated?  Diagnosis of exclusion

• dogs: granulomatous, pyogranulomatous on head/face, paw, often multiple lesions, cause unclear. 
• cats, horses: eosinophilic granulomas or plaques, lots of presentations, could be due to insect bites, hypersensitivity, injection rxn, etc.

• cutaneous reaction pattern, not a diagnosis
• caused by allergy - environmental, food, fleas, mosquitos, idiopathic
• bacterial infections
• feline eosinophilic granuloma: often idiopathic, cutaneous, mucocutaneous or oral mucosal lesions of cats.  Papular, nodular, raised oval to linear, firm, erythematous to yellow-orange, chin and caudal thighs common but can be anywhere
• feline eosinophilic plaque: severe pruritus, single or multiple, well-circumscribed, raised, erythematous, eroded, oozing, often ulcerated plaques, oval to linear, abdomen and medial thighs, secondary infection common.

• common oral mucosal ulcer of cats
• commonly licking, usually upper lip near filtrum, may be unilateral or bilateral
• early lesion in flea allergy dermatitis?  
• infection common
• 

• common especially in spring and summer
• single or multiple papules and nodules
• round, elevated, well-circumscribed
• skin and hair coat NORMAL
• no pain or pruritus
• hypersensitivity?  Trauma?  body-clipping?  Injection sites due to silicone-coated needles?

• fairly common, three nematodes involved: habronema muscae, Habronema majus, drachia megastoma
• pruritus mild to severe
• hypersensitivity?  Fly picks up larvae in feces and deposits in eye/muzzle/prepuce/wound, Larvae cause habronema.  Eosinophils!

• non-neoplastic, simple sac-like structure with EPITHELIAL LINING
• classify based on lining, sometimes contents.  Usu solitary, esp head, neck, trunk, proximal limbs
• Follicular (common), epitrichial (common), dermoid (rare), sebaceous (rare)

• solitary, well-circumscribed, round, smooth, firm to fluctuant lesions, dermal to SQ (NOT attached to deeper tissue). Aspiration gives white cheesy material
• infundibular: from infundibular portion of hair follicle
• isthmal: arise from isthmus
• matrical: arise from inferior section
• hybrid: 2-3 types of follicular epithelium

• common in dogs, uncommon in cats
• duct obstruction
• usually solitary, well-circumscribed, smooth, tense to fluctuant
• BLUE HUE, alopecic
• head, neck, limbs
• aspiration = clear fluid
• 

• developmental abnormality, congenital and hereditary
• solitary or multiple, often along dorsal midline
• boxers, kerry blue terriers, rhodesian ridgebacks

• rare
• sebaceous duct cyst
• solitary, firm, <1cm

• oral papillomatosis: self-limiting in YOUNG dogs, regress spontaneously
• cutaneous exophytic: ANY AGE, single or multiple, head, eyelids, paws, regress spontaneously
• 
• cutaneous inverted papilloma: usually under 3 years, abdomen, groin, limbs, digits, DON'T regress spontaneously
• 
• pigmented plaques: YOUNG adults, mostly mini schnauzers and pugs
• 
• pigmented papules: rare, long-term glucocorticoids or compromised

• papillomatosis like dogs, young horses, on haired skin of muzzle and distal limbs, spontaneous resolution in 2-4 months
• aural plaques, flat, in ear, don't progress or resolve.  Fly vector.  
• gentical warts, may evolve into invasive SCC in chronic
• papillomatosis, can do any of the above

• two types
• fibropapilloma on teats and penis of young cattle (exophytic, BPV-1)
• multiple lesions of head, neck, dewlap of young cattle (BPV-2)
• both spontaneously resolve in 12 months
• epithelium AND FIBROBLASTS, not like horse/dog (those are just epithelial

• common in older cats, usually benign, often melanotic
• may be alopecic, ulcerated

• common in dogs, 98% benign, seen in older/adult.  Solitary or multiple.  Begin smooth, shiny, waxy, pink to orange papules, become cauliflower-like.  Can become hyperpigmented or ulcerated
• nodular hyperplasia, adenoma, epithelioma (less common, low grade malignancy, locally invasive but don't metastasize), carcinoma (less common. metastasize late in dz?)

• adult dogs and cats
• benign or malignant, usu solitary
• head, neck, dorsal trunk, limbs
• commonly blue and cystic
• may be solid and ulcerated

• very common in older dogs, solitary or multiple
• trunk, abdomen, proximal limbs
• well-circumscribed, soft to firm and SQ
• may be multilobulated and pedunculated

• common in dogs, benign to super malignant
• less common in cats and horses, usually benign
• dermal or SQ
• variable appearance
• Boxers, Boston Terriers, Lab retrievers, beagles, schnauzers, shar peis

• 50% of tumors in dogs under 2 years old
• Langerhans cells
• usually solitary, head pinnae and limbs
• appear suddenly
• "button tumor", often ulcerated.  
• Spontaneous remission in 3-4 months

• dogs, 70% are benign in haired skin, adult/aged.  
• usually solitary
• head (eyelid, pinna), trunk
• lesions on digits, scrotum and lip/oral are more commonly malignant

• variable biologic behavior, usually solitary and benign in younger
• common in older grey horses, esp perineum and tail. Also pinna, periocular, distal limbs
• 2/3 metastasize eventually, usu no clinical signs

• most common equine skin neoplasm
• 3-6 years old
• fibropapilloma
• inguinal>head>axilla>abdomen>thorax>neck>distal limbs
• locally aggressive, no metastatic
• multifactoral causes.  Genetic (quarter horses), viral (bovine papilloma), skin trauma
• occult: mildest, superficial, around eyes or mouth, neck, sheath, shoulder
• verrucous: slow growing, seldom aggressive, like face, neck, axilla, groin, sheath, coronary band
• nodular: large and alopecic nodules, more aggressive when ulcerated or traumatized, like periorbital, groin, sheath
• fibroplastic sarcoid: locally invasive, irregularly nodular, ulceration and exudation, may resemble exuberant granulation tissue
• malevolent: rare aggressive and invasive, irregularly nodular, may infiltrate lymphatics, potentially involve local LN (not metastatic)

an unpleasant sensation that provokes the desire to scratch

• irritation or allergy
• pruritic papular eruption
• dogs: rump, inguinal, posterior thighs
• cats: neck rump
• fewer symptoms = MORE FLEAS, because less hypersensitivity (IgE kills the fleas)

genetically predisposed inflammatory and pruritic skin disease with characteristic clinical features associated with IgE abx most commonly to environmental allergens

a genetically predisposed inflammatory skin disease with clinical features identical to atopic dermatitis but with NO IgE antibodies to environmental allergens

• early age at onset (6-36 months), familial history or breed predisposition, initially seasonal (pollen season).  Progressive. 
• signs: hives, recurrent otitis externa, facial and pedal pruritus, axillary +/- inguinal pruritus, generalized pruritus.  
• CONTACT DERMATITIS - face, feet, axillary
• staph, malassezia, pyotraumatic, acral lick, anal sacculitis, hyperhidrosis

• adult onset
• lesional or nonlesional pruritus, protracted seasonality, +/- asthma, pruritus stops with glucocorticoids
• pruritic ears, face, head/neck, generalized, miliary dermatitis, traumatic alopecia, eosinophilic granuloma complex.  NO HIVES because cats are sneaky

• 1.5 to 6 year onset
• can be seasonal or nonseasonal
• variable presentation (nonlesional pruritus, urticaria, symmetrical eosinophilic folliculitis), COPD.  Pruritus stops with glucocorticoids

• no genetic predisposition, ANY age (after 7-14 days of sensitization)
• variable clinical presentation (skin or not).
• canine signs: persistent urticaria, atopy-like pruritus, recurrent acute moist dermatitis, lumbosacral/scabies-like/generalized pruritus
• feline: SAME AS ATOPY facial otic head neck generalized pruritus, miliary dermatitis, traumatic alopecia, eosinophilic granuloma complex
• equine: atopic-like pruritus, pruritic or non-pruritic urticaria,

• cheyletiella yasguri, C. blakei, C parasitivorax
• no host specificity, 3 wk life cycle.  Surface parasite, cement eggs to hair shaft.  
• Variable clinical signs, often none or dorsally oriented walking dandruff (seborrhea +/- pruritus, scabies-like pruritus)
• STARTS AT TOPLINE AND WORKS DOWN

• very common
• genetic predisposition to allergy
• mini-mosquitos, "no-see-ums"
• seasonal
• thinly haired skin first, face around eyes.  Horses rub, cause alopecia, more places to bite. UNDER MANE, tail head. Can attach to hair and walk down to skin
• eggs laid in damp areas
• feed dusk to dawn

• culicoides hypersensitivity (summer)
• pediculosis (winter)
• stall vice (in stalls)
• psorioptic mange (winter)
• oxiuriasis (only on rear, not face)
• allergy

• rare primary keratin disorder of dogs and cats
• onset at or near birth, lifelong.  Many variations, difficult to control.
• Jack Russels, norfolk, golden, american bulldog, CKCS.  There are genetic tests

• disease of HAIRED skin (pads and nose normal) with metabolic or systemic problems.
• rare (female rottweilers and huskies)
• stunted, non-cutaneous defects, hard to manage.

• keritinization defect with susceptibility to Malassezia hypersensitivity (westies only?)
• Onset between 6 and 12 months
• variable greasiness and pruritus
• eliminating yeast allows successful management
• Looks like atopy, but in this case the cutaneous signs CAUSE the itch (timing--HISTORY)
• smell!  Look in folds for yeast and bacteria, treat for yeast and see what's left (won't go back to normal).
• R/O allergy

• edge hyperkeratosis in nose and footpads, flaking, dull coat, ceruminous otitis, seborrheic dermatitis
• early onset, worsens with age
• involves all keratinized surfaces, susceptible to malassezia or secondary bacterial.
• No systemic complaints
• inflammation causes increased epidermal turnover, causing increased grease, which increases bacteria and yeast, which causes scarring, = TECA.  Self-perpetuating
• common in Cocker, english springer spaniel, westie, EBD, beagle, basset

• congenital abnormality of pilosebaceous unit causing follicular hypoplasia (=hairless breed) and abnormal sebacious and/or epitrichial sweat glands (and bronchial glands).  
• Prone to heat stroke and dry skin, comedones (plugged follicles because no sebaceous glands), lead to milia/closed comedone and sterile furunculosis.  Need anti-comedone therapy!  And moisturizing--start early
• Worse as get older, hard to manage.

• common, onset at any point in life, may not involve ALL keratinized surfaces
• susceptible to secondary bacterial or malassezia
• variable systemic signs
• includes cradle cap (self-curing within 1 month), low-fat diet, malassezia overgrowth (foldy skin), hypothyroid, epitheliotropic lymphoma

• low incidence, onset at any point in life.  May not involve ALL keratinized surfaces
• susceptible to secondary bacterial or malassezia
• variable systemic signs.  
• Fastidious groomers, so dry or greasy uncommon. 
• low humidity, cheyletiella dermatitis, liver dz.  
• primary seborrhea is greasy, secondary is flaky.

• many causes, indicates serious disease
• large sheets of skin
• rare but important
• drug induced, lupus, FeLV, thymoma vs non-thymoma,

• hyperkeratotic plaques over pressure points
• environmental trigger (like laying on a hard floor)
• don't soften unless changing environment, this is a PROTECTIVE thing

• common in middle-aged to old dogs (boxer, boston, EBD)
• rare symptomatology
• keratin builds up but doesn't wear off, long fronds on nose.  Similar to digital disuse hyperkeratosis

• uncommon, associated with prolonged periods of limited exercise--keratin builds up but doesn't get worn down.  
• rare symptomology
• goes away once they start walking again

• common
• singular, multiple or persistent episodes
• variable symptomology
• evaluate chronic for malassezia or demodex.  
• idiopathic.  Can be in cats that don't groom.  Once they get it they keep it forever
• face, feet, caudodorsum (sebaceous glands.  
• Blackheads first, cat doesn't care.  Could turn into sterile furunculosis, so treat!
• topical keratolytics, glucocorticoids, possible abx, retinoids, stridex/alcohol/listerine

condition of abnormal hair patterns, predominantly loss or reduction

abnormal amount of hair growth over body

partial or complete absence of hair from areas of the body where it normally grows

• most common endocrine disease
• need T4 to start anagen phase of hair growth, initial hair loss in frictional areas, moves to everywhere.  
• signs: mental dullness/lethargy, weight gain/obesity without increase in appetite, heat-seeking behavior, skin changes, cardio signs, neuropathy and myopathy, repro system irregularities, coagulopathy sometimes? tragic face
• hair loss esp on caudal thigh, tail, patchy over ventral trunk.  Rat tail, spares head, topline and distal extremities (don't shed as often).  FRICTIONAL AREAS

• rare
• lethargy/obesity
• seborrhea sicca, matting of hair.  
• bilaterally symmetric truncal alopecia (including ear tips)
• disproportionate dwarfism, mental dullness, constipation, hypothermia, bradycardia (congenital hypothyroid)

PUPD, polyphagia with weight loss, hyperactive, v/d, CV or resp abnormalities, unkempt haircoat, matted or greasy or dry, claws grow FAST and long

• most common
• constitutional signs always present
• predictable pattern: systemic signs, altered hair coat (slow growth), hair loss (thinner by 6 months)
• PUPD, polyphagia (1st sign), hepatomegaly, pot-belly, skin changes (6months), repro changes (clitoral hyperplasia or testicular atrophy), hypertension, excessive bruising and poor wound healing. 
• predisposed to infection, increased panting, neuro.
• Pred head!  muscle loss, myotonia (down on hocks).
• Truncal hair loss, topline and belly, spares head, tail and inner limbs?
• excessive glucocorticoids decrease everything: sebum, epidermal turnover, hair growth, alters coat color, predispose to comedones, decreased elasticity, calcinosis cutis (calcinosis ossification)

• constitutional signs develop CLOSE TO HAIR LOSS (SAME TIME)
• glucocorticoids +/- sex hormones
• head, tail and inner limb-sparing alopecia
• clitoral hyperplasia, perianal donut (increased testosterone), tail gland hyperplasia, calcinosis cutis with no hair loss, coat color changes.  Hair loss at collar = sex hormone changes

• rare
• skin changes variable and atrophic
• ears flop or curl, coat color changes, SKIN FRAGILITY SYNDROME, phlebectasia - bursting vasculature making petechiae?,

• patterned alopecia, no constitutional signs, variable coat color alteration
• androgen and estrogen receptors on hair follicles, different with gender and body site. 
• males lose fur at tail head, caudal thighs, at shoulder blades and collar
• females lose over hips, caudal thigh, behind hear and ventrum

• hyperestrogenism: ovarian cyst/tumor, constant estrus, patterned alopecia, nipple enlargement, comedones
• hyperprogesteronism: ovarian tumor, growth hormone production = acromegaly and DM.  Cutaneous signs due to anti-androgen. Tragic face, widened dental arcade
• cutaneous pseudocyesis: hair loss ~6wk post-estrus, behavioral/mammary changes present, spontaneous resolution.
• primary anestrus: 
• estrogen-responsive alopecia: 
• resolved by neutering

• testicular neoplasia: tumors benign, estrogens produced by sertoli and seminomas (LINEAR PREPUTIAL ALOPECIA), testosterone produced by interstitial cell tumors.
• "normal" testes
• hyperandrogenemia
• primary testicular atrophy
• tx via castration
• hair loss around collar, tail head, behind shoulders and caudal thighs

• traditional medications given orally, topically or parenterally.
• Extra-label usage WITH INFORMED CONSENT (companion animals)
• Vet-pateint relationship NECESSARY

• environmental anti-infectives and parasiticides
• MUST FOLLOW LABEL
• no need for vet-patient relationship

• insecticide and arachnid-icide
• 8 months
• EPA

• One of the best
• ticks only not fleas
• dogs only
• EPA

• GREAT
• absorbs into sebaceous and replenishes skin, so monthly
• EPA

• DILUTE
• great for parasites, bacteria, fungal, pruritic, keratolytic
• smelly, drying, stains

• surface distribution: applied over back and spreads out, concentrates on skin and within sebaceous glands, sebaceous replenishes
• transdermal absorption: whole body circulation THEN concentrates in sebaceous glands, takes a few days

• insecticide and growth inhibitor, fleas and lice
• 30 days, no replenishment
• WEEKLY DOSING ON LABEL - ONLY ONE
• EPA

• insecticide, arachnicide, insect repellant, insect growth regulator
• dogs only, no replenshiment
• monthly or WEEKLY - ONLY ONE
• EPA

• broad-based parasiticide (fleas, ear and scabies mites, HWP, GI parasites, advocate adds lice, demodex, lungworms)
• FDA!!!

• insecticide and arachnicide, flea birth control
• replenishing
• EPA

• insecticide for cats
• insects and arachnids for dogs
• EPA

• insecticides, arachnicide, internal parasites
• FDA

• insecticide, rapid onset.  Fleas not ticks
• FDA (OTC now)

• flea/tick, protein-bound
• FDA
• extra-label for demodex, scabies mites

• fleas, intestinal parasites, tape wroms
• FDA

• Flea/tick
• protein bound
• 3 months
• oral, topical version for cats
• FDA
• demodex, scabies extra-label

• prevent flea egg hatch and larval molting
• okay for one animal household
• EPA

• avermectins, milbemycins
• paralysis of mites and insects
• no mammalian toxicity at licensed dose
• FDA
• external parasite disease  = HIGH dose, so no MDR1 (white feet don't treat)

• canine scabies, sarcoptes scabiei
• lives in epidermis
• lives in house 24h, barn 7d, fox den 60d
• burrowing, skin scrape!  Can scratch it off! 
• Ear tip crusts, pinnal-pedal reflex
• intense pruritus
• RARELY on topline, works its way up
• dx: intermediate skin scrape 25% effective, response to tx

• cat: allergy or parasite
• dog: parasite

• Notoedres cati
• cat and exotics scabies (sarcoptes too), rare, easy to find the mites.

• normal fauna, transferred to neonate while nursing, live in hair follicle
• don't feed on blood so no hypersensitivity (usu), not pruritic, self-curing, no genetics.
• dx: deep skin scrape, trichogram, pustular cytology
• Localized (<7 spots) or generalized (juvenile onset vs adult, which is triggered by systemic disease like Cushings - mite specific immuno-incompetence, genetic predisposition)

• long cigar mite
• genetic predisposition
• non-pustular
• face, feet, dorsal midline/caudal dorsum.  
• Facial and pedal pruritus
• mites are few and DEEP in follicle  
• Dogs are greasy and itchy.

• fleas.  Many species. 
• feed on blood, bite causes allergy/irritation.  
• LONG life cycle, leave town for 3 months and they'll be waiting.
• Eggs LAID ON HOST then fall off into environment, feed on adult flea's feces