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SA Medicine II Dermatology


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Dermatological Hx should include:
⬢Signalment: age, sex, breed, color
⬢Chief Complaint
⬢Age of Onset
⬢Pruritus, Seasonality, Progression, Travel, Contagion, Response to therapy, Environment
⬢General Medical History
Com'n Skin Dz's younger than 6 months
-Black Hair Follicle dysplasia
-K9 muzzle furunculosis (K9 acne)
-Cutaneous asthenia
-Juvenile Sterile granulomatous dermatitis and lymphadenitis (juvenile Cellulitis)
-Viral papillomatosis
Com'n Skin Dz's in 1-3 year old animals
-K9 Atopic dermatitis
-Color dilution alopecia
Com'n Skin Dz's in animals older than 6 yo
-Sertoli Cell tumor assoc. dysplasia
-Superficial necrolytic dermatitis
General quality of skin and hair to be noted
Is the hair dull, dry, brittle, oily, or thin? Is the skin thinned, hyperelastic, or thickened? Are there any pigmentation changes or abnormalities? Are there obvious lesions that will need special attention during closer examination?
Types of Primary Skin Lesions
Types of Secondary Skin Lesions
-Epidermal Collarette
-Lichenification (can be seen w/ hyperkeratosis & pigmentation involved)
Types of Primary or Secondary Skin Lesions
-Follicular casts
-Comedo (blackheads)
Pustules may be:
Follicular, non-follicular, large w/ multiple follicles (usually immunosuppresive)
Most com'n sign of Sarcoptic mange
Alopecia and crusts around the ears
Terms used to describe lesion configuration
-Iris (target)
Com'n Lesions found on the Head
-Atopic dermatitis
-Juvenile sterile granulomatous dermatitis & lymphadenitis
Com'n Lesions found on the Ear
-Atopic dermatitis
-Food intolerance
-Fly bite dermatitis
-Solar dermatitis (feline)
Com'n Lesions found on the Eyelid
Com'n Lesions found on the Nasal Planum
-Discoid lupus erythematosus (collie nose)
-Nasodigital hyperkeratosis
-Pemphigus foliaceus
-Sterile pyogranuloma syndrome
-Uveodermatological syndrome
Com'n Lesions found on the Lips
-Indolent ulcer
-Oral papillomatosis
Com'n Lesions found in the Oral Cavity (mucosa)
-Eosinophilic granuloma
-Erythema multiforme
-Plasma cell stomatitis
-Pemphigus vulgaris
-Systemic lupus erythematosus
Com'n Lesions found on the Mucocutaneous Junctions
-Epitheliotropic lymphoma
-Erythema multiforme
-Mucocutaneous pyoderma
-Superfical necrolytic dermatitis (TEN)
Com'n Lesions found on the Chin
Com'n Lesions found on the Neck
-Feline atopy
-Flea bite hypersensitivity, feline
-Injection site reaction
Com'n Lesions found on the Ventral Chest
-Bacterial folliculitis
-Sternal callus
-Contact dermatitis
Com'n Lesions found in the Axillary region
-Acanthosis nigricans
-Atopic Dermatitis
-Malassezia dermatitis
Com'n Lesions found on the Back
-Atopic dermatitis
-Bacterial folliculitis
-Flea bite hypersensitivity
-Schnauzer comedo syndrome
-Seborrhea, primary
Com'n Lesions found on the trunk
-Bacterial folliculitis
-Sebaceous adenitis
Com'n Lesions found on the Abdomen
-Atopy, feline
-Eosinophilic plaque
-Psychogenic alopecia
-Solar dermatitis
-Contact dermatitis
-Atypical mycobacteriosis
-Pelodera derematitis
Com'n Lesions found on the tail
-Anal sac dz
-Food intolerance
Com'n Lesions found on the Legs
-Acral lick dermatitis
Com'n Lesions found on the Paws
-Adverse food reaction
-Foreign body
-Malassezia dermatitis
-Pemphigus foliaceus
-Plasma cell pododermatitis
-Contact dermatitis
-Superficial necrolytic dermatitis (NME)
Com'n Lesions found on/near the Claws
-Lupoid onychodystrophy
-Bacterial paronychia
-Systemic lupus erythematosus
-Pemphigus foliaceus
Superficial Skin Scraping
Performed over large area, collecting abundant material
-Taken from intact, crusted lesions of p's suspected of having Sarcoptes
-Elbows, chest, pinna margins com'n areas
Dermanyssus gallinae
(Poultry mites)
May be collected w/ superficial skin scrapings
Tend to be very scarce
Scrape near excoriated sites
Acetate tape impressions may be used
Lynxacarus radovsky
(Feline Fur mite?)
Attach to hairs over spine
-Dx via Trichography
Deep skin scrapings
Taken most often when there is a suspicion of demodicosis
-Shar Pei's, particularly deep scrapings needed
Pelodera strongyloides
Free living nematode may invade skin of dogs
-600um larvae seen w/ deep skin scrapings
Direct examination of plucked hairs
If ringworm suspected, KOH clearing of keratin may help
Trichography especially useful when:
-Demodex suspected in difficult area to scrape
-Cat fur mites
Increased number of Hairs in Anagen:
Suggests an endocrinopathy or follicular arrest
Skin surface cytology types
Direct impression
Acetate Tape impression
Cotton tipped-swab
Acetate tape impression
Tape pressed against dry skin, mounted on a slide, then stained w/ blue part of diff-Quik stain
Bacterial culture and susceptibility testing indicated in:
-Cases responding poorly to appropriate antimicrobial therapy
-Suspected deep Pyoderma
-Cases when resistant or uncom'n org's are suspected d/t chronicity or unusual presentations (atypical mycobacteria, Pseudomonas, Nocardia)
Abx in regard to C/S
Should be d/c 48-72 hrs prior to culture
Deep skin infections best cultured via:
Best cultured using a skin biopsy, external surface of sample is excised and discarded
-Let lab know that you want it minced and if a special media is needed
Dermatophyte Test Media (DTM)
Contains Abx, an antifungal, and a pH indicator (phenol red- selectively metabolize available proteins before carbs, producing alkali metabolites and turning the media red)
3 most com'n spp of dermatophytes in SA's
-#1- Microsporum canis
-Microsporum gypseum
-Trichophyton mentagrophytes
Wood's Light Examination
Emits 253.7nm UV light reacting w/ tryprophan metabolites in some spp to emit a yellow-green fluorescence
-Hairs should be exposed for 3-5 minutes
Skin biopsy indicated when:
1) Have lesions suspicious of neoplasia
2) Have lesions consistent w/ a dz which is most readily dx'd by biopsy
3) Display an unusual presentation
4) Have a poor response to therapy
5) Might require long-term and/or expensive therapy
-Be able to recognize a M. canis macroconidia
-Trichophyton mentagrophytes are cream-colored colonies, powdery to granular, microconidia usually round, macroconidia cigar shaped, may have spiral shaped hyphae
Objectives Lect. 2
1. Be able to describe and provide examples of resident and transient bacteria of dogs and cats.
2. Describe the therapeutic approach for acute moist dermatitis.
3. Know the factors which may adversely affect the response of a skin infection to antibiotic therapy.
4. Be able to compare acute moist dermatitis with pyotraumatic folliculitis and furunculosis.
5. Understand the causes and therapeutic options for acral lick dermatitis.
6. Describe the typical clinical presentation of feline opportunistic mycobacterial infection.
Defense Mechanisms of normal skin
Physical (hair, s. corneum)
Chemical (sebum, sweat)
Microbial (competition for niches, antimicrobial substances)
Resident Bact of dogs
#1- S. intermedius
Clostridium spp
Propionibacterium acnes
Actinobacter spp
Micrococcus spp
Transient bact of dogs
E. coli
Proteus mirabilis
Corynebacteria spp
Bacillus spp
Pseudomonas spp
Transient flora of cats
B-hemolytic strep
E. coli
P. mirabilis
Pseudomonas spp
Bacillus spp
Topical Antimicrobials
Chlorhexidine, providone-iodine (careful w/ cats), ethyl lactate, benzoyl peroxide (best ABx topical tx), Abx
Most com'n Abx used for skin infxns
*know mech's of axn*
Cephalexin (80% of time for pyoderma)
Cefpodoxime (simplicef)

Should be given w/ systemic abx tx until pyoderma resolved
Staphage Lysate: S. aureus phage lysate for SC injection.
ImmunoRegulin: killed Propionibacterium acnes preparation for IV injection.
Autogenous staphylococcal bacterins: not widely used.
Levamisole: 2.2 mg/kg q. 48 hrs.
Cimetidine: 10 mg/kg TID.
IFN-α: human recombinant form has been used at 1-3 million IU/dog po or sc q. 1-3 days.
Superficial Bact Infxns
-Acute moist Dermatitis
-Mucocutaneous pyoderma
-Superficial bact folliculitis
Deep Bact Infxns
-Pyotraumatic folliculitis and furunculosis
-Bacterial folliculitis and furunculosis
-Nasal folliculitis and furunculosis
-Muzzle folliculitis and furunculosis
-Interdigital pyoderma
-GSD Pyoderma
-Acral lick dermatitis & furunculosis
-Subcutaneous abscesses
-Bact pseudomycetoma
-Opportunistic mycobacterial granuloma
Acute Moist Dermatitis- General info
-AKA Hot spot, Pyotraumatic dermatitis (PTD)
-Uncom'n in cats
Acute Moist Dermatitis- Etiopathogenesis
-Dvlp in minutes/hours in response to focused self-trauma
-Most often 2ndary to FAD, but many other causes
Acute Moist Dermatitis- Therapy
-Clip/Clean wound
-Non-steroid antipruritic spray (lidocaine, oatmeal)
-Topical corticosteroid/Abx spray (gentamycin/betamethasone)
-Oral pred
-Abx for 14-21 days
Impetigo- General info
Puppy pyoderma and bullous impetigo represent 2 subtypes
-NOT contagious
Impetigo- Etiopathogenesis (puppy form)
-Coagulase positive Staph. spp cultured from pustules
-May occur in assoc w/ parasitism, poor nutrition, or poor sanitary condtns, or sporadically in healthy dogs
Bullous Impetigo- Etiopathogenesis
Occurs secondary to immunosuppressive conditions such as Cushing's, hypothyroidism, and diabetes mellitus
-Staph, Pseudomonas may be involved
Impetigo- Signalment
2-12 mos (puppy pyoderma)
Middle age+ (bullous)
Impetigo-Clinical presentation
-Non-follicular pustules in the abdominal and axillary skin
-Usually non-pruritic
-Ruptured pustules dvlp into crust and epidermal collarettes
Impetigo- Therapy
-Topical Abx ointment (mupirocin)
-Abx shampoo (chlorhex, benzoyl peroxide products)
-Systemic abx if severe
Mucocutaneous Pyoderma- general
Mucocutaneous Pyoderma- Etiopathogenesis
Mucocutaneous Pyoderma- Signalment
GSD's predisposed, but may occur in any breed/age/sex
Mucocutaneous Pyoderma- Cx
-Scale, erythema, and swelling initially
-Lip commisures and wings of nostril most com'nl affected
-Lesions progress to painful crusts, exudate, and depigmentation
Mucocutaneous Pyoderma- Dx
Clinical recognition
Skin biopsy
Response to therapy
Mucocutaneous Pyoderma- Tx
-Topical abx
-Systemic abx 3-6 wks
Superficial Bacterial Folliculitis- general
AKA Staph folliculitis
Com'n in dogs (short hair > long hair)
Superficial bacterial folliculitis- Etiopathogenesis
-S. intermedius in most cases
-2y to demodicosis, irritant contact derm, atopic derm, FAD
Superficial bacterial folliculitis- Signalment
More com'n in short-haired breeds
Superficial bacterial folliculitis- Cx
-Variably pruritic
-Follicular papules, pustules
-Elevated tufts resemble hives
-Multifocal alopecia
Superficial bacterial folliculitis- Dx
-Clinical recognition of Cx
-R/O demodex and dermatophytosis
-Cytology--> PMN's and cocci
Superficial bacterial folliculitis- Tx
-Tx signs or work up underlying condtns
-Abx shampoo 1-2/wk
**Systemic abx for min. 3 wks
Dermatophilosis- General
AKA Cutaneous Steptotrichosis
-Very rare in SA's
Dermatophilosis- Etiopathogenesis
Dermatophilus congolensis
-Aerobic, Gram +
-Flagellaed, motile zoospores
-Does NOT penetrate intact skin
-Diplococci "railroad tracts"
Dermatophilosis- Cx
-Papules and coalescing circular crusts
-Crusts are adherent, yellow, incorporate hair
-Cats abscess more often
Dermatophilosis- Dx, Dogs
-Crusts minced in water, stained w/ Wright-Giemsa
-Orthokeratotic and Parakeratotic
Dermatophilosis- Dx Cats
Biopsy and histopath of nodule is the method of choice
Dermatophilosis- Tx, Dogs
Abx Shampoo and crust removal
-Penicillin V 14-21 days
Pyotraumatic folliculitis and furunculosis- General
-Hot spot
- Pyotraumatic Dermatitis (PTD)
Pyotraumatic Folliculitis and Furunculosis- Cx
-Eroded to ulcerated, alopecic, erythematous, purulent macules
-Pruritis and pain
-Com'n on cheek and neck
Pyotraumatic Folliculitis and Furunculosis- Dx
-Cx signs
-Skin biopsy
Pyotraumatic Folliculitis and Furunculosis- Tx
-Same as hot spot tx
-More resistant to tx
-Continue Abx 14d past Cx
-Discontinue pred ASAP
Bacterial Folliculitis and Furunculosis- General
-AKA Deep folliculitis, furunculosis, cellulitis
-May be assoc. w/ systemic illness
-Com'n in dog, rare in cat
Bacterial Folliculitis and Furunculosis- Etiopathogenesis
**S. intermedius most com'n
-Pseudomonas, Proteus, E. coli more com'n in deep than superficial
-Secondary to demodecosis, dermatophytosis, immunosuppression
Bacterial Folliculitis and Furunculosis- Cx
Lesions localized or generalized
-papules, pustules, hemorrhagic bullae, sinuses, nodules, etc
Bacterial Folliculitis and Furunculosis- Dx
-By Cx, may be febrile
-Cyto. exam to see bacteria and rule out fungal
-Tissue eosinophilia com'n
Bacterial Folliculitis and Furunculosis- Tx
-Severe cases may require IV fluids and parenteral Abx
-Frequent bathing w/ Abx shampoo
-Tx 2-3 wks past cure, Often 6-12 wks
Nasal Folliculitis and Furunculosis- General
AKA Nasal pyoderma
S. intermedius most com'n
Nasal Folliculitis and Furunculosis- Cx
-Painful papules/pustules on dorsal muzzle
-Rapidly progressive
Nasal Folliculitis and Furunculosis- Ddx
-Pemphigus foliaceus, discoid lupus erythematosus, eosinophilic folliculitis and furunculosis, demodecosis, Dermatophytosis
Nasal Folliculitis and Furunculosis- Tx
-Abx for 7-14d post-cure
-Soak and clean lesions TID w/ Chlorhex or Burrow's solt'n
Muzzle folliculitis and furunculosis- General
AKA- Canine Acne
Muzzle Folliculitis and Furunculosis- Etiopathogenesis
-Probably 2ndry infxn of a sterile process
-Underlying etio may be a genetic keratinization disorder aggravated by local trauma
Muzzle Folliculitis and Furunculosis- Signalment
-Young dogs
-Short-haired breeds
Muzzle Folliculitis and Furunculosis- Cx
-Early papules are sterile follicular papules around the lips and on the chin
-Chronic-- lg bleeding/oozing pustues dvlp
Muzzle Folliculitis and Furunculosis- Tx
-Modify behavior which predispose chin to trauma, if possible
-Mild cases may respond to regular Antibact cleaning/topical Abx
-Infected- ORal abx for 4-6wks
Interdigital Pyoderma- General
-AKA pododermatitis, pedal folliculitis/furunculosis
Interdigital Pyoderma- Etiology
-Primary or idiopathic
-S. intermedius most com'n, but G - orgs may be involved and more resistant to Tx
-One foot--> FB's (awns), trauma, ostiomyelitis, fungal
-Multiple feet--> Hypothyroidism, Demodecosis, Atopy, food allerg., immunodef, hookworms, Pelodera, FB's
Interdigital Pyoderma- Dx
-Rule out underlying causes w/ skin scraping, fungal culture, skin biopsy, FB exploration, Radiography
Interdigital Pyoderma- Tx
-Tx w/ syst ABX for 6-8wks or 2 wks past clinical resolution
-Topical Abx/chorhex may help
-Chronic cases may me difficult to tx and require debridement, and or fusion podoplasty
GSD Pyoderma- General
-Hereditable dz of GSD's
-Underlying immunodeficiency
-Results in inflamm that is out of proportion to the underlying cause
GSD Pyoderma- Cx
-Rump, thighs, back, ventral abd, chest most affected
-Papules, pustules--> crusts, ulcers, fistulae
GSD Pyoderma- Tx
-Tx underlying dz if ID'd
-Clip and clean matted/ulcerated lesions
**Systemic ABX for 8-12 wks
-ABX shampoo
-Chronic ABX Tx may be needed
Acral lick Dermatitis and furunculosis- General
AKA- Lick Granuloma
-Chronic lesions carry poor prognosis for resolution
Acral lick Dermatitis and furunculosis- Etiology
-Single lesions = Boredom, local trauma, jt pain
-Multiple lesions = Atopic derm or hypothyroidism
-Often 2ndrly infected w/ Stapylococcus/other bact
Acral lick Dermatitis and furunculosis- Signalment
-Lg Breeds
-Middle age to old dogs
Acral lick Dermatitis and furunculosis- Tx
** Long term Tx, 6-12wks ABX
-Behavior modification
-Amytriptyline, fluoxetine, CLOMIPRAMINE, variable efficacy
-No single modality works in most cases
SQ Abscesses- General
-Frequent in cats, uncom'n in dogs
SQ Abscesses- Etiology
-Bite wounds (Pasturella multocida)
-Non-healing may result from immunosup, Y. pestis, mycobacterial infxn, Actinomyces, Nocardia spp
SQ Abscesses- Dx
Cx w/ evidence of skin puncture is characteristic
**serology to check FeLV/FIV status**
Bacterial pseudomycetoma- General
-AKA Botryomycosis, cutan. bact. granuloma
Bacterial pseudomycetoma- Etiology
-2ndry to penetrating wound most com'n
-Staph most com'n
-Pseudomonas, Proteus, Strep, Actinobacillus less com'n
Bacterial pseudomycetoma- Cx
Single/multiple nodules w/ draining fistulae
Bacterial pseudomycetoma- Dx
Skin biopsy
Histopath shows granulomatous to pyogranulomatous inflammation surrounding tissue granules composed of bact and eosinophilic material
-Bact C & S
Bacterial pseudomycetoma- Tx
-Surgical excision
-Systemic ABX
Opportunistic Mycobacterial Granuloma- General
-AKA= Atypical mycobacterial granuloma
-Uncom'n in cats
-Rare in dogs
-Guarded prognosis
Opportunistic Mycobacterial Granuloma- Etiology
-Facultative pathogens found in soil
-Ubiquitous organisms (Mycobact. fortuitum, M. chelonei, M. phlei, M. smegmatis)
Opportunistic Mycobacterial Granuloma- Cx
-SQ nodules, ulcers, draining tracts and fistulae
-Most com'n location is the inguinal rgn in cats
-Dogs--> nodules on pinnae
Opportunistic mycobacterial granuloma- Dx
-Demonstrate acid fast orgs
-C & S= alert lab of your suspicion, difficult to grow
Opportunistic mycobacterial granuloma- Tx
-Surgical excision when practical
-Enrofloxacin, Doxycycline
**Months of tx usually necessary (4-6wks past clinical cure)
Plague- General
-Cats/rodents much more susceptible
-30-40 spp of wild rodents as natural reservoirs
-Transmitted b/t rodents/fleas
-Bubonic, pneumonic, septicemic forms
Plague- Etiology
-Yersinia pestis
-G Neg, fac anaerob, nonmotile, bipolar staining coccobacillus
-Rocky mtn states and Hawaii
Plague- Cx
-Febrile (105-106F)
-Submand, retropharyng, cervical LN's abscess and drain (bubo formation)
-Bubonic form may progress to septicemic form and pulmonic form (least com'n)
Plague- Dx
-Cytology of exudates and aspirates: monomorphic population of Gram Neg bipolar coccobacilli
Plague- Tx
Gloves/mask should be worn
-Tx should begin BEFORE laboratory confirmation
Fungal sections Objectives
1. Be able to discuss the three species of dermatophytes which most commonly infect small animals.
2. Describe three clinical presentations of feline dermatophytosis.
3. Describe how to reach a diagnosis of Malassezia dermatitis.
4. Know the geographic distribution of the systemic mycoses.
5. Know which fungal infections carry the greatest risk of zoonosis.
Superficial Mycoses
Dermatophytosis- General
-Overdiagnosed d/t over-reliance of Wood's light examination
Dermatophytosis- Etiology
-Fungal infxn of the s. corneum, hair, and/or claw by:
-Microsporum, Trichophyton, or Epidermophyton spp.
Dermatophytosis- 3 most com'n org's
Microsporum canis
M. gypseum
T. mentagrophytes
Microsporum canis
-Most often acquired from cats
-Spindle-shaped macroconidia w/ thick walls and 6+ cells
-White to buff, cottony colony
Microsporum gypseum
-Most often acquired from soil
-Ellipsoidal macroconidia w/ THIN walls and 4-6 cells
-Beige, granular colonies
Trichophyton mentagrophytes
-Most often acquired from rodents or enviro
-Numerous grape-like clusters of microconidia, few cigar-shaped macroconidia, spiral hyphae
-White to cream, powdery to granular colony
Dermatophytosis- signamlent
-Long haired cats
-Yorkies, dalmatians
-Poor nutrition, immunosuppressed at incr risk
Miliary Dermatitis
Characterized by multiple, small, crusted papules and pruritis
-RARELY caused by M. canis, much more com'n from Flea allergies
Dermatophytosis- Cx- Dogs
-Annular lesions w/ alopecia, follicular papules, scale and crust most com'n
-Folliculitis, furunculosis and scarring alopecia seen w/ T. mentagrophytes
Nodule w/ purulent exudate
Dermatophytosis- Dx
-Wood's Light
-Trichography (ectothrix spores)
-Skin biopsy (not as sensitive as DTM)
Dermatophytosis- Tx
-Environmental deconamination
-spores viable for 18mos
-1:10 or 1:20 bleach
-Destroy Bedding/grooming aids
-Topical-- CLOTRIMAZOLE, miconazole, terbinafine
-Shampoos--chlorhex, miconazole
-Rinses-- Lime sulfur
-Microsized (Fulvicin U/F)
-Ultramicrosixed (Gris-PEG)
Malassezia Dermatitis- General
-Yeast dermatitis
-Com'n in dogs, rare in cats
Malassezia Dermatitis- Etiology
M. pachydermatis (syn Pityrosporum canis)is a normal inhabitant of K9 skin/ears
-Other factors may predispose to overgrowth, various dermatites, FAD, etc
Malassezia Dermatitis- Cx
-Generalized or regional
-Lichenification and hyperpigmentation if chronic
-Paronychia and claw infxns w/ brown discoloration and waxy accum on claws and nail biting
Malassezia Dermatitis- Dx
Skin surface cytology
-Direct impression
-Acetate tape impression
-Cotton-tipped swab
Skin biopsy less sensitive b/c outer half of s. corneum lost during processing
Malassezia Dermatitis- Topical Tx
Ointments: Clotrimazole, miconazole, terbinafine
Shampoos and rinses: Chlorhex, miconazole
Malassezia Dermatitis- Systemic Tx
Itraconazole, fluconazole
***Griseofulvin is NOT effective***
Candidiasis- General
AKA- Moniliasis, Thrush
-Normal inhabitants of alimentary, upper resp, genital mucosa
Candidiasis- Signalment
-Dogs w/ Diabetes mellitus, Cushing's, Hypothyroidism, neoplasia, taking immunosuppressive drugs
Candidiasis- Cx
-Grey plaques/ulcers in mucocutaneous jxns, ear canal, intertriginous areas, interdigital areas
-Papular to pustular lesions
Candidiasis- Dx
-Cutaneous cytology
-Narrow-based budding org's
Candidiasis- Tx
-Correct underlying dz
-Control moisture by clipping and cleaning, when approp.
-Topical antifungals
-Systemic antifungals
Subcutaneous Mycoses
-Often introduced via trauma, grow in living tissue
-Eumycotic mycetoma
Eumycotic mycetoma- General
-Tropical dz
-Rare in US
Eumycotic mycetoma- Etiology
-Most com'nly caused by Pseudoallescheria boydii
-Gains entry via wound contamination
Eumycotic mycetoma- Cx
-Solitary nodules, draining tracts and tissue grains
-Head/limbs most affected
Eumycotic mycetoma- Dx
Fungal culture
Eumycotic mycetoma- Tx
-Surgical excision or limb amputation
-Poor prognosis
Phaeohyphomycosis- General
-AKA Chromomycosis
-Pigmented hyphae
Phaeohyphomycosis- Etiology
-Many dematiaceous soil saprophytes are capable of causing this
-Bipolaris spiciferum
-Xylohypha bantiana
Phaeohyphomycosis- Dx
Cytology and histopath
-Granulomatous to pyogranulomatous dermatitis and panniculitis
Phaeohyphomycosis- Tx
-Poor prognosis w/ recurrence com'n
-Amphotercin B
-Wide surgical excision
Zygomycosis- General
-Mucormycosis, entomopthoromycosis
Zygomycosis- Etiology
-RARE in dogs & cats
-Multiple fungi cause this
-Rhizopus, Mucor, Absidia, Conidiobolus, Basidiobolus
Zygomycosis- Cx
-Solitary or multiple ulcerated, draining nodules on extremities
Zygomycosis- Tx
-Surgical excision or debulking along w/ antifungal therapy
Sporotrichosis- General
-Exudates and tissues from cats are infective
Sporotrichosis- Etiology
-Sporothrix schenckii
-Mycelial form in environment, yeast form in tissue
-Gains entry via wound
-Dogs- splinters and thorns
-Cats- Contaminated claws
Sporotrichosis- Cx
-Cutaneous, cutaneolymphatic, disseminated froms may occur concurrently
-Lesions begin distally and travel up
-Cats dvlp abscesses and cellulitis under puncture wound
-Dissemination often evident at necropsy
Sporotrichosis- Dx
**Suspect this dz when an abscess or wound responds poorly to tx**
-Fluorescent Ab testing
Sporotrichosis- Tx- Dogs
-Supersaturated solution of potassium iodide (SSKI) is the tx of choice
-If iodism is a concern, use ketoconazole or itraconazole
Sporotrichosis- Tx- Cats
Itraconazole is Tx of choice since cats are more susceptible to SSKI and Ketoconazole SE's
-Monitor for hepatotoxicity, anorexia, vomiting, wt. loss
Rhinosporidiosis- General
RARE in dogs
NOT reported in cats
Rhinosporidiosis- Etiology
Rhinosporidium seeberi
Difficult to culture
Mucous Mb trauma may predispose to infxn
Rhinosporidiosis- Tx
Surgicl excision of polyps is often curative
-Dapsone or Ketoconazole may help w/ recurrence
Systemic Mycoses (Cutaneous manifestations)
Hematogenous and lymphatic spread of deep or systemic mycoses may lead to skin infxn
Primary cutaneous infxn is extremely rare
Blastomycosis- General
UNCOMMON in dogs
VERY RARE in cats
-MS, OH, MO river valleys
-NOT zoonotic by aerosol from infected pets, but humans have gotten infected at the same time as pets
Blastomycosis- Etiology
Blastomyces dermatitidis, a dimorphic saprophyte
-Inhalation of spores from mycelial growth in enviro
**Infection established in the lungs**
Blastomycosis- Signalment
1-5 yo, male, outdoor, hunting dogs most com'nly affected
Blastomycosis- Cx
-Skin lesions in 20-40% of infected dogs
-Planum nasale, face, and nail beds most com'n sites
-Papules, plaques, nodules, ulcers, draining tracts, abscesses
-Multi-system involvement:
fever, dry harsh lung sounds, ocular lesions, lameness and bone involvement, wt loss
Blastomycosis- Dx
-Cytology of exudates shows round to oval yeast
-Fungal culture
-Radiograph chest, and lame limbs
Blastomycosis- Tx
-Itraconazole Tx of choice**
-Amphotericin B and Ketoconazole alternatives
-Fair prognosis if no brain involvement or bad lung dz
Coccidiodomycosis- General
-San Joaquin Valley Fever
-Valley Fever
-UNCOM'N (dogs) to RARE (cats)
-Southwestern US
Coccidiodomycosis- Etiology
Coccidiodes immitis, a soil-borne fungus
-Epidemics may follow wind, recent rain, or earthquakes
-Inhalation of arthroconidia
-Most asymptomatic
Coccidiodomycosis- Signalment
1-4 yo male dogs predisposed
Coccidiodomycosis- Cx
-Multi-system involvement:
fever, anorexia, wt. loss, depression
-Skin lesions 2ndry to disseminated dz
**Papules, nodules, ulcers and draining tracts usually over site of infxn in DISTAL long bone**
Coccidiodomycosis- Dx
Cytology and histology may work, but not com'nly
-Dx based on clinical signs, radiograph findings, and serology
-Fungal culture should be avoided
Coccidiodomycosis- Tx
Guarded prognosis w/ frequent relapses
-Ketoconazole, itraconazole, fluconazole, Amphotericin B
Cryptococcosis- General
-RARE in dogs
-UNCOMMON in cats
**Pigeon droppings serve as the main reservoir**
-NOT Zoonotic
Cryptococcosis- Etiology
Cryptococcus neoformans is a ubiquitous, saprophytic, round, yeast-like fungus
-Forms a capsule when growing in tissue, hindering Ag presentation
-Rte of infxn--Inhalation
Cryptococcosis- Signalment
-Siamese cats susceptible
-In dogs, young adults
-Doberman, Great Danes, American Cockers
Cryptococcosis- Cx
-Skin lesions in 40% of cats, 20% of dogs
-Nasal cavity involved in 80% of cats (polyps)
-Papules, nodules, ulcers, draining tracts
-Other signs: CNS, ocular, wt loss, mild fever
Cryptococcosis- Dx
-Cytology of nasal exudates, skin exudates, CSF, tissue impressions
-Fungal culture, histopath, serology
Cryptococcosis- Tx
-Long term tx - 7-10 mos
-Serial latex agglutination testing help to monitor response
-ITRACONAZOLE drug of choice
-Fluconazole for CNS involvement
-Ketoconazole- Use w/ CAUTION w/ cats
-Amphotericin B and Flucytosine used less com'nly d/t toxicity
Histoplasmosis- Etiology
Histoplasma capsulatum
-Survives best in soils w/ bat and bird excrement
-Inhalation probable route of inoculation
Histoplasmosis- General
UNCOMMON in dogs/cats
-Most cases in MI, MO, OH River valleys
Histoplasmosis- Signalment
-Young cats and dogs (<4yo)
-Pointers, Weim's, Brittany spaniels
Histoplasmosis- Cx
-Disseminated dz most com'n
-Skin infrequently affected
-Papules, nodules, ulcers, tracts
-Usually multiple lesions
-Face, nose, pinnae
-Depression, wt loss, anorexia, dyspnea
-Dogs--> Lg bowel diarrhea
Histoplasmosis- Dx
-Org's usually numerous in exudates and tissues
-Intracellular small, round yeast in mononuclear cells
-Basophilic center and light halo caused by shrinkage
-Fungal culture should be avoided (let the pro's do it)
-Serology unreliable
Histoplasmosis- Tx
-Fluconazole (CNS)
-Ketoconazole less effective
Parasitic Skin Diseases I: Mites, Helminths, & Flies
1. Be able to describe the clinical features, diagnosis, and treatment of canine demodicosis.
2. Be able to recognize the mites affecting dogs and cats.
3. Understand why ivermectin is more toxic to certain individuals.
4. List three techniques for the collection of Cheyletiella mites.
Demodicosis- General
AKA-Follicular mange, Red mange
-Com'n in dogs
-RARE in cats
Demodicosis- Etiology in Dogs
-Demodex canis
-Normal resident of skin
-Juvenile onset assoc. w/ immune abnormalities and genetics
-Adult onset assoc. w/ Immuosuppression, metabolic dz, neoplasia
Demodicosis- Etiology in Cats
Demodex cati assoc'd w/ systemic dz (FIV, FeLV, diabetes mellitus, SLE)
-Plumper mite
Localized Demodicosis
-5 or less discrete lesions
-Periocular, perioral, limbs most com'nly affected
-Mild erythema, alopecia
Generalized Demodicosis
>5 patches, lg rgns, or generalized
-Any rgn of the body, esp feet
-Mild-severe erythema, alopecia
-Swelling, sinus tracts may dvlp
-May dvlp deep bact folliculitis/furunculosis
-Greasy and malodorous
Felin Demodicosis
-Periocular, head, neck alopecia
-Erythema, scale, crust
-Ceruminous otitis externa
-Pruritis variable, severe w/ D. gatoi
Demodicosis- Tx- dogs
-Localized, should resolve w/o tx
-Topical benzoyl peroxide gel or rotenone
-Repeat monthly skin scapings until 2 negatives
-Amitraz (Mitaban)- *ONLY approved tx
-Don't bathe b/t dips
-Milbemcyin (Interceptor)
Demodicosis- Tx- cats
-Often self-limiting
-Weekly lime-sulfur dips for 4 wks if generalized or D. gatoi
Canine Scabies- Etiology
-S. scabiei var. canis
-Front legs short w/ UNJOINTED pedicles and suckers
-Burrow in the s. corneum
Canine Scabies- Cx
-Pruritis severy by 3-4wks
-Positive pinnal-pedal reflex
-Ventral chest, abdomen, legs, elbows, pinnal margins
-Papules, alopecia and erythematous, excoriated crusted macules
Canine Scabies- Dx
-Superficial skin scrapings positive less than 50% of time
-When scabies suspected, but not seen, trial tx w/ Revolution
-Skin scrapings over large areas
Canine Scabies- Tx
**Tx ALL dogs in house**
-Selamectin (Revolution) every 2 wks for 3-4 tx's
-Ivermectin SQ wkly for 3-4wks
-Lime-sulfur dips
-In many cases the pruritis will worsen at first, by 14d improvement should be seen
Notoedric Mange- General
-AKA Feline scabies, Head mange
-HIGHLY contagious
Notoedric Mange- Etiology
-Notoedres cati (a sarcoptiform mite)
-Smaller than sarcoptes, look similar, w/ dorsal anus
Notoedric Mange- Cx
-Pinnae, face, neck, legs, feet, perineum mostly affected
Notoedric Mange- Dx
Skin scrapings reveal mites w/ UNJOINTED pedicles (shorter than sarcoptes) w/ suckers
Notoedric Mange- Tx
Ivermectin a good alternative
Cheyletiellosis- General
"Walking Dandruff"
-Dogs, cats, rabbits
Cheyletiellosis- Etiology
Dogs- C. yasguri
Cats- C. blakei
Rabbits- C. parasitivorax

Deck Info