Skin: deep pyoderma

Introduction

• May be life-endangering dermatoses.
• Cause : predisposed by demodicosis , hypothyroidism , hyperadrenocorticism , trauma or immunosuppression, eg neoplasia or internal disease, may be idiopathic (especially German Shepherd pyoderma).
• Signs : papules, pustules, furuncles, discharging sinuses; bacterial infection of dermal and subcuticular tissues.
• Diagnosis : history, clinical signs, microscopy, histopathology, bacteriology.
• Treatment : antimicriobial/antibiotic therapy.
• Prognosis : varied according to bacterial infection.

Diagnosis

Clinical signs

• Deep folliculitis .
• Few infected follicles → discrete papular lesions.
• Many infected follicles → alopecia, tissue swelling and inflammation.
• Papules → pustules → hemorrhagic bullae → ulceration +/- fistulae → crusts.
• More common on pressure points and trunk.

• Pyotraumatic folliculitis .
• Mimics acute moist dermatitits with satellite lesions and no response to cleansing and glucocorticoid therapy.
• More common cheek and neck.
• Breeds affected - Rottweiler and Golden Retriever .

• Sudden onset painful, erythematous swelling on bridge of nose.
• Mainly dolichocephalic breeds.

• Papules, pustules, comedones and draining tracts.
• Chin and lips.
• Little pain.

• Acute: feet swollen, painful, discharge pus, paronychia.
• Chronic: nodules, ulceration, fistulae and furunculosis.

• Almost exclusively middle-aged German Shepherd Dog.
• Papules, pustules, furunculosis, hyperpigmentation and alopecia: dorsum, gluteal region, ventral abdomen and thighs.
• Advanced cases generalized, sparing head and front feet.

• Acral lick furunculosis .
• Distal limbs.
• Firm, raised, hairless, hyperpigmented at periphery, eroded or ulcerated centrally.

• Thickened skin: elbows, hocks, sternum.

Diagnosis

Differential diagnosis

• Acute moist dermatitis .
• Non-bacterial infectious skin diseases.
  • Dermatophytosis .
  • Demodicosis .
• Immune-mediated skin diseases.
  • Drug eruption.
  • Other bacterial skin disease .

Sequelae

Prognosis

• Good if predisposing factors treated.
• Bacteremia and sepsis are uncommon sequelae.

• Good if predisposing factors treated.

• Often spontaneous regression at puberty.
• May need topical corticosteriods to prevent recurrence.

• Variable degrees of scarring and sterile dermal granulomas remain, ? protect foot by restricting activity or wearing boots.

• Moderate in general.
• Many dogs require life-long antibiotic therapy.
• Tendency to recur.

• Large lesions heal leaving thin hairless epithelium which is easily traumatized and re-infected.
• Important to identify underlying disease.

Expected response to treatment

• Regression of clinical signs, usually within 8-12 weeks.

• Regression of clinical signs usually within 2-3 weeks.

• Formation of thin hairless epithelial layer with no further improvement on antibiotic therapy, usually within 8-12 weeks.

Sources

Publications

Refereed papers

• Carlotti D N, Guaguere E, Pin D, Jasmin P, Thomas E & Guiral V (1999) Therapy of difficult cases of canine pyoderma with marbofloxacin - a report of 39 dogs. JSAP 40 (6), 265-270.
• Scott D W et al(1998) Efficacy of clindamycin hydrochloride capsules for the treatment of deep pyoderma due to Staphylococcus intermedius infection in dogs. Can Vet J 39 (12), 753-756.
• Hill P B & Moriello K A (1994) Canine pyoderma. JAVMA 204 , 334-340.
• Mason I (1993) Selection and use of antibacterial agents in canine pyoderma. In Practice129-134.
• DeManuelle T C et al(1985) Determination of skin concentrations of enrofloxacin in dogs with pyoderma. Am J Vet Res 59 (12), 1599-1604.
• Thoday K L (1980) Canine pruritus; an approach to diagnosis - Stage II - Infestations and infections. JSAP 8 , 449-458.