1A & 1B. The distribution of pustular skin lesions on the face of the dog in this case.
A 9-month-old neutered male Labrador retriever was referred to the Small Animal Teaching Hospital of the University of Prince
Edward Island for evaluation of a one-week history of pyrexia, a markedly swollen right tarsus, pronounced submandibular lymphadenopathy,
and progressive pustular to erosive, nonpruritic, crusting skin lesions. A week before referral, the owner had first noticed
an enlarged left submandibular lymph node and a pustule on the lip. When the dog had been presented to the referring veterinarian
the following day, it had been febrile (104.9 F [40.5 C]) and nonweightbearing on its right hindlimb because of a swollen
and painful right tarsus. Pustular lesions had erupted over its nose and ears.
2. Pustular and secondary erosive ulcerative lesions on the inner pinna and in the external auditory meatus.
The results of a complete blood count had revealed a slight monocytosis, and the results of a serum chemistry profile and
urinalysis had been unremarkable. Radiographic examination of the right hock had revealed soft tissue swelling. In-house cytologic
examination of joint fluid from the right tarsus had revealed no etiologic agents. The referring veterinarian had treated
the dog with intravenous fluids, antibiotics (ampicillin 18 mg/kg intravenously b.i.d.; trimethoprim-sulfadiazine 30 mg/kg
once a day; and cefoxitin sodium 18 mg/kg intravenously b.i.d.), and a nonsteroidal anti-inflammatory agent (flunixin meglumine
1 mg/kg orally once a day). The dog's condition had not changed over the next four days except for a temporary resolution
of its fever. The day before referral, the veterinarian had administered a single dose of prednisone (2 mg/kg orally). The
dog's vaccination status was current, and the dog had no history of travel outside of Nova Scotia.
Physical examination and differential diagnoses
3. Pustular and secondary erosive lesions on the dog's prepuce.
On physical examination, the dog was in fair body condition and weighed 60.3 lb (27.4 kg), but it was depressed, febrile (103.1
F [39.5 C]), and tachypneic (60 breaths/min). The dog had tacky mucous membranes and was estimated to be 5% dehydrated. We
noted pustular lesions on the concave aspect of both pinnae, in the external auditory canals, on the muzzle and chin, around
the eyes, and on the prepuce (Figures 1-3). Many of the pustules had ruptured and were oozing serosanguineous discharge. A serous bilateral ocular discharge and depigmentation
of the nasal planum were evident. The dog's prepuce was swollen, with ulcerative lesions at the mucocutaneous junction (Figure 3). Both submandibular lymph nodes were markedly enlarged, and the prescapular lymph nodes were mildly enlarged. Multiple freely
movable, mildly painful, fluctuant, subcutaneous nodules ranging in size from 1 to 2 cm in diameter were palpable on both
sides of the dog's thorax. The dog was nonweightbearing on its right hindlimb because of a markedly swollen, painful, and
warm right tarsus. All remaining joints were clinically normal.