Sterile Nodular Diseases in Dogs and Cats I

Canine sterile nodular panniculitis (SNP) is a sterile inflammatory disease of the panniculus that is often confused with deep pyoderma because it can cause draining tracts with exudate that may be purulent and/or with necrotic fat. Nodular lesions and/or thickened skin may also be seen. The most commonly affected areas are the trunk and neck, and the most common skin lesions are dermal or subcutaneous nodules. Australian shepherd dogs, Brittany spaniels, Dalmatians, Pomeranians, and Chihuahuas may have a breed predisposition.
Diagnosis is made by biopsy of the nodules and/or associated draining tracts; fine needle aspirates are often undiagnostic. Histopathology showed neutrophilic and histiocytic inflammation in either a nodular, septal, or combination of these patterns. In some cases the inflammation may extend in to the dermis.1 Because infectious disease organisms (bacteria, mycobacteria, fungi, protista, protozoa) can cause a nodular panniculitis, special stains and/or cultures are highly recommended before commencing treatment. [...]