Page 1509 - Clinical Small Animal Internal Medicine

164 Canine Sterile Papular and Nodular Skin Diseases 1447

PCR are necessary. This is particularly true for mycobac- frequently in certain breeds and within litters. Vaccine
VetBooks.ir teria and Leishmania. reactions have been postulated as the cause of juvenile
cellulitis, but the role of vaccine or other viruses in the
disease development remains unclear. A nonviral infec-
Therapy
tious etiology has also been considered but attempts to
Surgical excision can be curative for solitary nodules or isolate bacteria and fungi have not been successful.
plaques. Systemic treatment is often needed for multi-
ple lesions, including immunosuppressive doses of Signalment
glucocorticoids or other immunomodulating agents.
The use of tetracycline and niacinamide combination Most cases are young puppies less than 4 months old,
was shown to be effective for long‐term management in with a few reported cases in older dogs. No sex predi-
a case of SGPS. A trial with this combination is war- lection has been reported. Breeds that appear to be pre-
ranted before more potent immunosuppressive drugs disposed include golden retrievers, dachshunds, Gordon
are used. Tetracycline/niacinamide is used at 250 mg setters, and Weimeraners. Other breeds reported include
of each for dogs less than 10 kg, and 500 mg of each in the Labrador retriever, Siberian husky, miniature poo-
dogs more than 10 kg q8–12h. If tetracycline is una- dle, Chesapeake Bay retriever, Lhasa apso, and mixed‐
vailable, doxycycline at 5 mg/kg q12h can be used. If breed dogs.
shortage of doxycycline occurs, minocycline can be
substituted for doxycycline. Clinical Signs
Prednisone or prednisolone can be used at 2.2–4.4 mg/
kg q24h PO until resolution of the skin lesions (usually Early clinical signs consist of edematous moist dermati-
10–14 days), then the medication can be tapered to the tis affecting mainly the eyelids, lips, and muzzle. The
minimal effective dose (see treatment for sterile nodular affected skin rapidly develops papules and pustules.
panniculitis). Most cases require long‐term alternate‐day Lesions are characterized by severe edema, fistulation,
glucocorticoid therapy to avoid reoccurrence. Refractory and drainage with copious purulent discharge and crust
cases may require the addition of other immunomodulat- formation. Purulent otitis externa and conjunctivitis are
ing agents like ciclosporin or azathioprine. also common; the pinnae are often severely swollen and
may develop ulcerative lesions. Affected skin is usually
painful. Submandibular and prescapular lymphadenopa-
Prognosis
thy is commonly present. Concurrent neurologic signs
The prognosis is good. The condition may resolve spon- and orthopedic problems have been reported preceding
taneously or take a waxing and waning course. Most cases or associated with the signs of juvenile cellulitis. The
required prolonged use of immunomodulatory drugs. patient may be lethargic and depressed and older dogs
may present with more severe systemic signs and pyrexia.

Juvenile Cellulitis
Diagnosis
Canine juvenile cellulitis, also known as juvenile pyo- Clinical differential diagnoses include angioedema in
derma, puppy strangles, or juvenile sterile granuloma- acute cases and as lesions progress; staphylococcal pyo-
tous dermatitis and lymphadenitis, is an uncommon derma, demodicosis, and adverse cutaneous drug reac-
lymphocutaneous disease. It is characterized by a sterile tion should also be considered. Other less likely
granulomatous or pyogranulomatous dermatitis and differential diagnoses include neoplasia (cutaneous lym-
lymphadenitis and usually affects young puppies. phoma, mast cell tumor) or infectious causes such as
nocardiosis, actinomycosis, mycobacterial infections,
and subcutaneous opportunistic mycoses. Diagnosis is
Pathogenesis
often based on characteristic clinical presentation, but
The cause of juvenile cellulitis is unknown. Cytologic can be confirmed by cytologic or histopathologic find-
examination of aspirates of affected lymph nodes and ings. Tests may include fine needle aspirates of lymph
skin lesions does not reveal infectious agents, and cul- nodes, impression smears or skin scraping, cytology or
ture results of intact lesions are always negative for bac- skin biopsy. Cytology from fine needle aspirates of
terial and fungal growth. In addition, the condition affected lymph nodes reveals a sterile granulomatous or
responds dramatically to treatment with glucocorticoids, pyogranulomatous inflammation. Histopathologic find-
suggesting an immune dysfunction. There may be a ings usually reveal granulomatous or pyogranulomatous
heritable component as it has been documented more dermatitis which may extend into the panniculus.