A challenging case: A febrile dog with a swollen tarsus and multiple skin lesions


A challenging case: A febrile dog with a swollen tarsus and multiple skin lesions

The condition that these clinicians suspect in this Labrador is considered a late-onset manifestation, even though the dog is only 9 months old.

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.