566 DISEASES/DISORDERS
Special stains of histopathologic samples: help identify causative agent.
Surgical excisional biopsies: much more accurate than punch biopsy specimens in
most cases; punch biopsies do not provide a sample deep enough to make the diag-
nosis.Histopathologic lesions: required to make a diagnosis of panniculitis; determine sep-
tal, lobular, or diffuse inflammatory infiltrate by neutrophils, histiocytes, plasma cells,
lymphocytes, eosinophils, or multinucleated giant cells; identify necrosis, fibrosis, or
vasculitis (Figures 38.11–38.13).THERAPEUTICS
Single lesions: cured with surgical excision.
Multiple lesions: require systemic medications.
Positive culture results require appropriate antifungal, antibacterial, or antimycobac-
terial treatment.
Sterile nodular panniculitis: systemic treatment with steroids; prednisolone
(2.2 mg/kg daily) until lesions completely regress (3–6 weeks); after remission, grad-
ually taper dosage over 2 weeks; may need slower taper to minimize chance of recur-
rence; many patients cured; some patients require low-dose alternate-day treatment
to maintain remission.Oral vitamin E: may control mild cases.
Oral azathioprine 1 mg/kg or 50 mg/m^2 PO q24h then tapered: alternative when
steroids are contraindicated.
Cyclosporine 5–10 mg/kg PO q24h: alternative for sterile idiopathic panniculitis.
Cycline antibiotics: tetracycline 250 mg PO TID for dogs<10 kg; 500 mg PO TID
dogs>10 kg; doxycycline 10 mg/kg PO q24h; minocycline 5 mg/kg PO BID; often
administered with niacinamide 250 mg PO for dogs<10 kg and 500 mg PO for dogs
>10 kg.COMMENTS
Monitor CBC, platelet count, chemistry profile, and urinalysis if immunosuppressive
agents or long-term glucocorticosteroids are used.
Infectious cases may require long-term therapy with high doses of medications.
Sterile idiopathic nodular panniculitis often responds rapidly to high doses of corti-
costeroids.
Young animals have a more rapid and complete recovery than older animals; older
patients may require a maintenance protocol.