Puppy strangles

Puppy strangles is a disease of puppies, also referred to as puppy head gland disease, juvenile pyoderma and juvenile cellulitis. It is a relatively rare condition and so, may not initially be considered when puppies are first presented with what appears to be staphylococcal pyoderma.^[1]

Puppy with juvenile cellulitis at 7 weeks old.^[2]

Causes

The cause of juvenile cellulitis is unknown. Cytologic examination of aspirates of affected lymph nodes, pustules, abscesses, and joint fluid rarely reveal bacteria, and culture results of intact lesions are always negative for bacterial growth, suggesting a nonbacterial etiology.^[1]

Symptoms

Symptoms of juvenile cellulitis are dermatitis of the face, otitis externa, regional lymphadenopathy, lethargy, depression and limb lameness. It is common for symptoms to appear after the puppies' initial vaccination at about 6 weeks of age. Puppies with juvenile cellulitis are quiet, alert and responsive. Investigation into the limb lameness will reveal no abnormalities. Tests on the puppies' ears will reveal no ear mites. Heart and respiratory rates remain within normal range. As the condition worsens many papules become visible on both pinnae. Small pimples begin to develop on the puppies' face, and severe lethargy begins to set in. Eating and drinking remain unchanged, and there is no vomiting or diarrhea. Numerous pustules begin to develop on the muzzle, the pinnae and around the eyes. As the condition worsens, puppies become unwilling to walk or stand. Submandibular lymph nodes and prescapular lymph nodes become enlarged. Shoulders, elbows, and carpi can be bilaterally painful on flexion and extension.^[1]

Lesions may also appear on the feet, abdomen, thorax, vulva, prepuce, or anus. Lesions typically fistulate, drain, and crust. Marked pustular otitis externa is common, with the pinnae frequently being thickened and edematous. Affected skin is often painful but not pruritic. Approximately 50% of affected puppies are lethargic and depressed, as in this case. Pyrexia, anorexia, and sterile suppurative arthritis, manifesting as joint pain, are inconsistent findings. Leukocytosis with neutrophilia, and normocytic, normochromic anemia may also be seen.^[1]

Misdiagnosis

Puppies first present with what appears to be staphylococcal pyoderma. Definitive diagnosis requires cytologic and histopathologic evaluations. Cytologic examination of papulopustular lesions of juvenile cellulitis reveals pyogranulomatous inflammation with no microorganisms, and carefully performed cultures are negative. Biopsies of early lesions reveal multiple discrete or confluent granulomas and pyogranulomas consisting of clusters of large epithelioid macrophages with variably sized cores of neutrophils. Cytological analysis of joint fluid often reveals sterile suppurative arthritis.^[1]

Treatment

The condition responds dramatically to corticosteroids, suggesting an immune dysfunction. Large doses of glucocorticoids are the treatment of choice (2–3 mg/kg). When the puppy's condition has resolved, prednisone is tapered off slowly over a period of weeks. Early and aggressive therapy is indicated; otherwise scarring may be severe. If cytological or clinical evidence of secondary bacterial infection exists, bactericidal antibiotics such as cephalexin, cefadroxil, and amoxicillin clavulanate should be prescribed.^[1]

References