Introduction and Pathophysiology

A common condition encountered in small animal practice, the aural hematoma is one seen across a variety of species and may be associated with an array of underlying causes or trauma. Management of the hematoma itself will be the author’s primary focus of this chapter, though care should be taken to evaluate the history and underlying etiology or contributing factors to each case in an effort to minimize complications and local recurrence.

The aural hematoma most often develops following trauma to the auricle, or pinna, resulting in vascular damage and subsequent hemorrhage within the subcutaneous space of its ventral/concave surface (Figure 8.1). Aural hematomas may be unilateral or bilateral in presentation. Direct trauma to the pinna, such as from an animal bite, may result in the initial hematoma formation in the dog or cat, though most cases are the result of self‐trauma associated with some other underlying pathology or infection. More often, the repeated trauma of the pinna slapping against the sides of the head, associated with pruritus and head shaking, creates the lesion. Etiologies associated with otic pruritus and head shaking include parasitic infestations (Otodectes sp.), bacterial or fungal infections, chronic otic foreign bodies (grass awns), or underlying allergic disorders, such as atopy, flea allergy dermatitis, or food adverse reactions. Less common etiologies may include inflammatory polyps, otic neoplasms, coagulopathies, or endocrine disorders.¹

While the size and shape of the pinna may play a role in the size and extent of the lesion formed, aural hematomas can be seen in all ear types of dogs and cats. Left unattended, the general progression of the lesion and associated clinical signs will often result in enlargement of the initial hematoma (associated with head shaking) followed by varying degrees of auricular scarring and contracture. In humans, this crumpled appearance of the ear is referred to as a “cauliflower ear,” which is an aural hematoma between the cartilage and perichondrium of the pinna often secondary to trauma. Untreated hematomas in animals are also at higher risk for abscess formation or cellulitis. Failure to treat these lesions most often results in prolonging the discomfort experienced by the patient and a poor cosmetic outcome for the conformation of the pinna (Figure 8.2).

Treatment options for aural hematoma include both conservative, medical management strategies and surgical techniques, which are further described within this chapter.