Download Infectious skin diseases

Defense mechanisms
•Physical barrier
•Chemical and biochemical barrier
•Biologic barrier
•Innate immunity
•Acquired immunity
E. Simko WCVM
Infectious skin diseases - viral
Poxviruses
Macules, papules, vesicles, pustules, crusts
Orthopoxvirus
Parapoxvirus
Capripoxvirus
Leporipoxvirus
Suipoxvirus
Avipoxvirus
E. Simko WCVM
Infectious skin diseases - viral
Contagious ecthyma (Parapoxvirus)
High morbidity and low mortality
Bovine papular stomatitis
Pseudocowpox (parapoxvirus)
Zoonosis (milker's nodules)
Bovine herpes mammillitis virus
E. Simko WCVM
Infectious skin diseases - viral
Other viral infections:
Canine distemper
Nasodigital hyperkeratosis (hard pad disease)
Foot-and-mouth disease (picornavirus)
Vesicular stomatitis (rhabdovirus)
Swine vesicular disease (picornavirus)
Vesicular exanthema (calicivirus)
E. Simko WCVM
Infectious skin diseases - viral
Diagnosis of viral infections:
• History
• Gross and histopathology
• Immunohistochemistry
• Electron microscopy
• Viral isolation
E. Simko WCVM
Infectious skin diseases
Superficial folliculitis
Deep folliculitis
• Furunculosis
• Adenitis
E. Simko WCVM
Infectious skin diseases - Bacterial
Pathogenesis: bacterial proliferation in epidermis
triggers superficial neutrophilic inflammation
• Superficial pustular dermatitis (impetigo)& folliculitis
Coagulase-positive Staphylococcus
• Dermatophilosis (Bo, Ov, Eq, rare in Ca, Fe)
Dermatophilus congolensis
• Exudative epidermitis of pigs (greasy pig disease)
Staphylococcus hyicus
E. Simko WCVM
Infectious skin diseases - Bacterial
Deep bacterial infections secondary to follicular
hyperkeratosis, immunosuppression, trauma et cet
• Staphylococcal folliculitis and furunculosis (Ca)
• Subcutaneous abscesses (P. multocida) (Fe)
• Granulomatous dermatitis M. lepraemurium (Fe)
E. Simko WCVM
Infectious skin diseases - Bacterial
• Footrot - Bacteroides nodosus +/- F. necrophorum
Benign (scald) and virulent form
• Necrobacillosis - F. necrophorum +/- B. melaninogenicus
Ovine and bovine interdigital dermatitis
• Bovine digital dermatitis (strawberry foot)
Associated with spirochetes
• Viral diseases (BVD, MCF, F&M…)
E. Simko WCVM
Infectious skin diseases - Bacterial
• Septicemia / endotoxemia
S. suis, Salmonella, Erysipelas
• Clostridial infections
(more details in muscle)
E. Simko WCVM
Infectious skin diseases
Dermatophytosis (ring worm)
• Microsporum and Trichophyton
• Zoonosis
• Fungi invade and damage keratinized tissues initiating
inflammation resulting in folliculitis/furunculosis
• Fungi die in the central areas of inflammation and are
viable peripherally forming peripheral red rings.
E. Simko WCVM
Infectious skin diseases - Mycotic diseases
Malassezia (M. pachydermatis)
Blastomycosis
Cryptoccocosis
E. Simko WCVM
Infectious skin diseases
Diagnosis of bacterial and mycotic dz
• Scraping
• Cultures
• Gross and histopathology
Nota bene !!!
• Pyoderma is usually secondary disease obscuring
primary disorders
• Therefore, treat it first and than submit skin biopsy
E. Simko WCVM
Infectious skin diseases
Diseases are due to direct effect of parasites
and/or hypersensitivity reaction
Diagnosis:
Scraping
Gross and histopathology
E. Simko WCVM
Infectious skin diseases - Ectoparasites
• Demodex canis live in the lumina of hair follicles
• Transmission occurs during nursing
• In juvenile dogs and immunocompromised adults
• Lesions: localized (face and/or forelegs) or
generalized scaling, erythema and alopecia
• Sarcoptes scabiei - highly contagious
• Mites burrow through the stratum corneum and
cause intense pruritus (hypersensitivity reaction)
E. Simko WCVM
Keratinization disorders
Seborrheic Disease Complex
• Abnormal cornification or sebaceous glands function
• Change from nonpathogenic to pathogenic bacteria
• Dry or greasy form
• Primary or secondary
E. Simko WCVM
Morphology of skin lesions - Primary or Secondary
E. Simko WCVM
Nutritional disorders
Zinc and Copper Deficiency
• Abnormal keratinization and pigmentation
Vitamin A
Vitamin E
E. Simko WCVM
Neoplastic skin diseases
Skin is a common site of neoplasms in most animals
• Epithelial tumors
• Mesenchymal tumors
• Melanocytic tumors
Diagnosis
• Fine needle aspirate
• Biopsy
E. Simko WCVM
Neoplastic skin diseases
E. Simko WCVM