Felis ISSN 2398-2950

Deep pyoderma

Introduction

• Bacterial infection affecting the dermis and possibly the subcutis, sometimes causing systemic illness; lesions can be local or generalized. Rare, except subcutaneous abscesses.
• Cause: predisposed by immunosuppression, eg FeLV or FIV infection demodicosis   Demodectic mange, endocrinopathy, trauma, may be idiopathic.
• Signs: papules, pustules, furuncles, discharging sinuses; bacterial infection of dermal and subcuticular tissues; scarring where lesions have healed.
• Diagnosis: history, clinical signs, microscopy, histopathology, bacteriology.
• Treatment: identification of cause, antimicrobial / antibiotic therapy.
• Prognosis: depends on cause.

Pathogenesis

Etiology

Generalized folliculitis, furunculosis

• See deep folliculitis and furunculosis.
• Bacterial, eg staphylococci, beta-hemolytic streptococci, Pasteurella multocida  Pasteurella multocida.
• Demodicosis Demodectic mange.
• Dermatophytosis Dermatophytosis.
• Drug eruptions.
• Endocrine abnormalities.
• Seborrhea Primary seborrhea.

Anaerobic cellulitis

• See cellulitis.
• Trauma, eg bites, puncture wounds.
• Foreign body.
• Surgery.
• Burns Burns.
• Neoplasia Skin: neoplasia.
• Indwelling catheter.

Subcutaneous abscesses

• Bite wounds.

Bacterial pseudomycetoma

• Trauma, eg bite wounds.
• Foreign body.
• Usually coagulase-positive staphylococci.
• Multiple organisms may be involved, eg Pseudomonas spp, Proteus spp, Streptococcus spp, and Actinobacillus spp.

Mycobacterial granuloma

• Cutaneous tuberculosis, Mycobacterium tuberculosis  Mycobacterium tuberculosis, M. bovis  Mycobacterium bovis.
• Feline leprosy, unknown cause, possibly M. lepraemurium  Mycobacterium lepraemurium.
• Opportunistic mycobacteria.

Actinomycosis

• Rare, several species implicated.

Actinobacillosis

• Rare, Actinobacillus lignieresii.

Nocardiosis

• Rare, Nocardia spp Nocardia spp.

Predisposing factors

General

• Immunosuppression (FeLV Feline leukemia virus disease, FIV Feline immunodeficiency virus disease), progestagen therapy.

Pathophysiology

• Superficial pyoderma   →   deeper into follicles (folliculitis)   →   rupture of follicular wall   →   pyogranulomatous perifolliculitis or furunculosis in dermis and subcutis   →   extension along tissue planes   →   fistulae on surface or cellulitis and panniculitis in subcutaneous and fatty tissues.
• Bacteria commonly involved include: staphylococci  Staphylococcus spp, Proteus spp , Pseudomonas spp Pseudomonas spp, E. coli  Escherichia coli.

Diagnosis

Treatment

Prevention

Outcomes