Auricular hematomas are small-to-large, fluid-filled swellings that develop on the concave surface of the pinnae in dogs, cats, and pigs. The pathogenesis for development of the lesions is unknown, but trauma from head shaking or ear scratching due to pruritus is almost always involved.
In dogs, the condition is seen with atopic dermatitis and food allergy in which the ear canals are the primary sites of allergic inflammation, pruritus, and secondary infection. In pigs, sarcoptic mange, pediculosis, and meal in the ears (from overhead feeders) have been implicated as a cause of head-shaking that has led to auricular hematomas. Bites from other pigs also may be at fault.
Treatment is surgical to allow drainage. After draining and flushing, several mattress sutures can be placed to eliminate the "pocket." Drainage and glucocorticoid instillation are successful in ~50% of cases. Drainage is best obtained with a butterfly connection or an IV catheter. Glucocorticoids are instilled to fill the cavity without causing skin distention. A short course of a low anti-inflammatory dosage of oral glucocorticoids is commonly added to this treatment. Addressing the underlying problem is important to prevent recurrence.
