Treating Otohematomas in Dogs with Intra-Lesional Corticotherapy
Authors: Pachaly José Ricardo , Quessada Ana Maria , Belettini Salviano Tramontin , Borges Talita Bianchin , Sala Pollyana Linhares , Tramontin Rafael Santos , Souza Marcos Vinicius Feltrim , Voltarelli-Pachaly Evandra Maria 
Published: June 2021

Background: Otohematoma is common in dogs and is characterized by blood accumulation between the skin and cartilage of the outer ear. While the etiology is related to trauma, most cases have a predisposing condition. Treatment must drain the hematoma and maintain appropriate skin apposition to the ear cartilage. Treatment can be surgical, but there are also conservative options such as puncture drainage, followed by intralesional injection of glucocorticoids. This alternative method is less invasive than surgery, with an equivalent success rate. This study aimed to describe intralesional injection of corticosteroids for the treatment of dogs with otohematoma at a veterinary clinic.Materials, Methods & Results: Otohematoma was diagnosed and treated in 23 dogs (14 males and 9 females, weighing 9.6 ± 2.7 kg) at a reference private veterinary clinic. The dogs were chemically restrained, and their ears were cleaned with chlorhexidine. The lower face of each ear with otohematoma was then punctured with a needle coupled to a syringe to drain the liquid. Following drainage, the equipment was removed and the collected liquid volume was measured. A 0.5 mg/kg dose of methylprednisolone acetate was prepared and diluted in saline (0.9% NaCl) to a volume equivalent to 1/10 of the previously drained content volume from the otohematoma. The prepared solution was then injected into the drained ear. Additionally, each patient was treated for the original cause of the otohematoma, according to conventional protocols. Eight animals (34.78%) had bilateral otohematoma and 15 (65.22%) presented with unilateral lesions. Leukocytosis was observed in most patients. Other laboratory alterations present in the studied dogs were thrombocytopenia, leukopenia, and anemia. Twenty (86.96%) patients presented with otitis externa. All patients were reassessed one week after the initial treatment, and 19 (82.60%) fully recovered. The remaining 4 (17.40%) required a new procedure to drain a small accumulation of liquid. Patients were then reassessed on the 15th day when full recovery was observed in 2 (8.7%). The remaining two (8.7%) underwent new drainage on the 15th day, accompanied by a new infusion of corticosteroids, returning recovered on the 21st day.Discussion: Consistent with the previous reports, unilateral otohematomas were more frequently observed in the present study. In most animals, the cause of otohematoma was otitis externa. This disease causes intense itching that leads to autotrauma, resulting in the rupture of vessels and accumulation of fluid between the skin and cartilage of the ear. Leukocytosis detected in the majority of patients was related to external otitis. The other hematological changes observed are common in the disease. The objectives of otohematoma therapy in dogs are to identify and eliminate the source of auricular pruritus, provide adequate drainage of the hematoma content, and maintain the appropriate apposition between the skin and cartilage in the ear. In all 23 patients in this study, these aims were met, culminating in favorable outcomes. The described method led to recovery for most patients (82.60%) in the first week and a success rate of 100% by the end of 21 days. These results observed in animal patients are similar to those seen in humans, where drainage leads to total regression of the disease. Glucocorticoids were chosen for treatment of otohematoma because of their anti-inflammatory effects. Additionally, methylprednisolone acetate, an ester whose absorption was very slow, was used to allow for a longer anti-inflammatory effect.