Bovine Dermatology

Question 1

What are the differentials for pruritic skin in cattle?

Answer 1

• Ectoparasites
• Photosensitization
• Fungal/bacterial infections
  
  • Fusarium, Aspergillus, leptospirosis
• Pseudorabies
• Dermatophytosis

Question 2

What is Pediculosis? cause, appearance, etc

Answer 2

• Caused by Lice
  
  • Biting - Mallophaga
    
    • Damalinia bovis
  • Sucking - anoplura
    
    • Haematopinus eurysternus
    • Linognathus vinus
• Distribution:
  
  • Neck & tail to generalized
  • Sucking lice also have facial distribution (muzzle/ears)
• Appearance:
  
  • Excoriation -
    
    • alopecia
    • ulcers
    • dryness/scale
• Sequelae:
  
  • Hide damage
  • weight loss
  • anemia
  • trichobezoar formation
• Dx: look for lice
• Tx:
  
  • Suckers - Injectable avermectin

Question 3

What are the causes of Mange in cattle?

Answer 3

• Mites:
  
  • Choriptes bovis
    
    • Leg mange, Foot and tail
    • Surface, non-burowing
    • have funnel feet
  • Psoroptes ovis
    
    • Sheep scab mite
    • Body mange
    • Surface, non-burrowing
    • Whisker legs
  • Sarcoptes scabiei
    
    • Head mange
    • surface, burrowing
    • look “stumpy”
    • Zoonotic
  • Demodex bovis & ghanesis
    
    • Hair follicles & glands
    • Most host-specific
    • Non-pruritic (nodular)

Question 4

Which causes of mange are most host specific?

Answer 4

Demodex >> chorioptes > sarcoptes > psoroptes

Question 5

Which causes of mange are the itchiest?

Answer 5

psoroptic & sarcoptic >> chorioptic >> Demodex

Question 6

how is mange diagnosed

Answer 6

• Skin scrape
• Dermatohistopathology - rarely picks up mites, shows characteristic lesions

Question 7

What is Chorioptic mange? distribution, appearance, etc

Answer 7

• Most common
• Surface, non-burrowing
• Risk factors:
  
  • stalled animals in winter
  • stocking density
  • dairy
• Distribution:
  
  • lower hind limbs
  • perineum
  • tail
  • scrotum
  • dead skin cells
• Appearance
  
  • papule
  • erythema
  • scale
  • crusts
  • ulcers
  • alopecia
• Sequelae
  
  • weight loss
  • Secondary skin infection
  • decreased production
• DX: skin scrape

Question 8

What is Psoroptic mange?

Answer 8

• Debilitating pruritis
• Surface, non-burrowing
• Control is challenging
• Risk factors:
  
  • Beef
  • cold months
• Distribution
  
  • Withers & tail to generalized
• Appearance:
  
  • Crusted popular lesions
  • lichenification
• Sequelae
  
  • irritability
  • weight loss
  • secondary skin infection
  • decreased production
  • Death (>40% of body)
• Dx:
  
  • skin scrape
  • Histopath: Hyperplastic eosinophilic dermatitis

Question 9

What is Sarcoptic mange?

Answer 9

• Debilitating pruritis
• Surface, burrowing
• Distribution:
  
  • face, pinna & neck to generalized +/- udder cleft
• Appearance:
  
  • papule, scaling, crusting, ulceration
  • alopecia, lichenification, and hyperkeratosis
• Sequelae:
  
  • lymphadenopathy
  • weight loss
  • ill thrift
  • pyoderma
• Dx: Deep skin scrape

Question 10

What is Demodectic mange

Answer 10

• Skin follicles, sebaceous and sweat glands
• Dame to neonate transmission
• Not pruritic
• Distribution:
  
  • face
  • shoulder
  • brisket
  • neck
• Appearance - nodular
• Sequelae - secondary pyoderma

Question 11

Does a negative skin scrape rule out mange?

Answer 11

NO

Question 12

How is mange treated/managed

Answer 12

• Topical acaricides 10-14 day intervals; 4-6x
  
  • lime sulfur, doramethrin, deltamethrin, coumaphos, diazinon, malathion, toxaphene
• Injectable Ivermectin - limited efficacy
• Isolate infected animals
• Decontaminate environment bedding
• Notify officials

Question 13

What are the differentials for masses and bumps in cattle?

Answer 13

• Papilloma
• Squamous cell carcinoma
• Demodectic mange
• Dermtophitosis
• Pemphigus Foliaceus
• Cutaneous lymphoma
• Stephanofilariasis
• Pseudocowpox
• Insect bite hypersensitivity

Question 14

What is Papillomatosis

Answer 14

• Caused by Bovine papilloma virus - 2 (BPV-2)
• Affects skin, reproductive, urinary, and GI
• Distribution:
  
  • head, neck, & withers
  • teats
  • penis
• Appearance:
  
  • white/tan/gray protruding masses with dry/horny surface
• Sequelae:
  
  • decreased hide quality
    
    • undesirable at shows
• Tx:
  
  • self-limiting
  • manual removal
  • cryotherapy

Question 15

What is Squamous Cell Carcinoma?

Answer 15

• Malignant neoplasia of Keratinocytes
  
  • “Cancer eye”
• Risk factors:
  
  • UV light
  • altitude
  • non-pigmented skin
  • tropical climate
• Distribution:
  
  • Ocular - lateral limbus/lower lid/3rd eyelid/medial canthus
  • Branding keratoma, back, pinna, limbs
• Premalignant appearance:
  
  • white hyperplastic plaque/papilloma
• Malignant appearance:
  
  • Proliferative or ulcerative
  • invasive, irregular nodular, pink, erosive, foul odor, necrotic
• Dx:
  
  • patient factors, gross appearance
  • Histopathology
• Tx:
  
  • surgical excision
  • laser therapy
  • Cryotherapy

Question 16

What is Dermatophilosis “rain scald”

Answer 16

• Agent: Dermatophilus congolensis
  
  • G+ aerobe, non-acid-fast, branching, filamentous
  • Infective stage: Zoospores
• Disease triad: Carrier + moisture + skin abrasions
  
  • Risk factors for decreased resistance:
    
    • prolonged rain / hosing
    • immunosuppresion
    • bugs
    • UV light
    • excessive grooming
• Transmission: Chronic carriers, flies, ticks, fomites
  
  • fall and winter months
• Distribution:
  
  • dorsum, distal extremities, muzzle
  • generalized
• Appearance:
  
  • thick crusts with moist concave skin beneath
  • +/- pain
• Sequelae:
  
  • generalized disease
  • superficial folliculitis
• Dx:
  
  • Grossly
  • Impression smear/cytology
    
    • railroad track cocci
  • Histopathology - layer cake
    
    • parakeratoic stratum corneum
    • dried serum
    • degenerating neutrophils
• Tx:
  
  • Keep dry
  • Oxytetracycline LA-200 (20 mg/kg IM)
  • PPG
  • Remove crusts, wash w/ betadine
    
    • Contagious!

Question 17

What is Staphnofilariasis?

Answer 17

• Nonseasonal
• Stephanofilaria stilesi - parasitic infection
• Intermediate hosts:
  
  • haematobia (biting fly)
  • Musca (house fly, face fly, etc)
• Districution:
  
  • ventral abdomen
• Appearance
  
  • hperkeratosis
  • alopecia

Question 18

What are the differentials for papular, pustular, vesicular and focal skin lesions?

Answer 18

• Ectoparasites - mange
• Dermatophilosis
• Pyoderma/Impetigo
• Dermatophytosis

Question 19

What is Impetigo?

Answer 19

• Agent: Stachylococcal sp
  
  • Subcorneal pustules not involving the hair follicle
• Risk factors:
  
  • dirty ewuipment
  • immunosuppresion
  • stress from parturition
• Distribution:
  
  • Ventrum - udder, abdomen, perineum, inguinal
  • face
• Appearance:
  
  • pustules to crusts
• Sequelae: Mastitis

Question 20

What is Furunculosis?

Answer 20

• Bacterial infection of the follicle that breaks through the follicular wall
  
  • Corynebacterium pseudotuberculosis
• Appearance:
  
  • hemorrhagic, raised raw lesion
  • exudative/hemorrhagic, painful
• Tx:
  
  • keep dry
  • Oxytet

Question 21

What are the differentials for scaling & alopecic skin?

Answer 21

• Ectoparsites - pediculosis, mange
• Dermatophytosis
• Photosensitization

Question 22

What is Dermatophytosis?

Answer 22

• Ringworm
• Fungal agent: Trichophyton verrucosum, T. mentagrophytes
• Risk factors:
  
  • young
  • immunosuppresseion
  • overcrowding
  • poor nutrition
  • warm/humid environment
• Transmission: direct, fomites
• Icubation: 1-6 weeks
• Distribution
  
  • keratinized skin - eyes, face, axilla, girth
  • generalized
• Appearance:
  
  • superfical or deep circular cursts
  • alopecia, scale wart-like
• Dx:
  
  • fungal culture
  • Trichography
  • Histopath - mimics acantholysis of PF
  • Woods lamp will NOT fluoresce
• Tx:
  
  • azole topicals
  • LimePlus dip
  • self limiting - 1-4 months

Question 23

What is Photosensitization

Answer 23

• Causes:
  
  • Primary - plants containing pyrrolizidine alkaloids
  • Secondary:
    
    • fungal/bacterial infections
      
      • Fusarium, Aspergillus, lepto
    • Neoplasa
      
      • lymphoma, heptic carcinoma
    • Chemical toxicitites
• Distribution:
  
  • unpigmented skin
  • white haired regions, face, dorsum
  • Eyes, coronary band, teat
• Apearance:
  
  • sever sunburn
  • Hyperesthesia; blistering, alopeciea
  • Erythema of unpigmented regions
  • pruritis
• Other syndromes:
  
  • Conjunctivitis
  • lameness
  • mastitis