In dogs, the lesions reported as eosinophilic granulomas histologically resemble the eosinophilic granuloma of cats, with marked collagen degeneration surrounded by a granulomatous and eosinophilic infiltrate. These lesions may be seen as ulcerated or vegetative masses in the oral cavity or, less commonly, as plaques, nodules, or papules on the lips and other areas of the body. Any breed may be affected, but Siberian Huskies and Cavalier King Charles Spaniels may be at greater risk.
Most lesions respond to corticosteroids, and therapy is usually oral prednisone or prednisolone (0.5–2 mg/kg/day initially, tapering the dosage throughout 20–30 days). Lesions recur in some dogs, in which case low-dose, every-other-day corticosteroid therapy is indicated.
Canine eosinophilic furunculosis is a closely related disease. It has been reported in many breeds but typically is seen in long-nosed large breeds or curious small breeds (eg, terriers) with potential access to wasps, bees, ants, spiders, etc. It is thus felt to be due to arthropod bites or stings. Consistent with this, the disease may be very rapid in onset, leading to nasal/muzzle swelling, exudation, and pain. Large, swollen erythematous lesions on the muzzle are the most common lesions, but in some dogs similar lesions may be seen on the head, periocularly and around the pinna. Impression smears often show eosinophils. While diagnosis is usually done on a clinical basis, histologic confirmation will show lesions similar to that of the canine eosinophilic granuloma but with more eosinophilic infiltration into the epidermis and follicular wall, a furunculosis, and fewer areas of eosinophilic debris-coated collagen. Treatment is as described for feline eosinophilic granuloma.
Last full review/revision May 2013 by Stephen D. White, DVM, DACVD