28 External Ear Conditions

28.1 Pinna

The pinna is embryologically formed, from six cartilage hillocks of His, which fuse to form the convoluted shape of the human pinna. It comprises skin over perichondrium on a cartilage skeleton. It acts as a ‘funnel’ to focus sound waves into the external ear canal; it also has some sound localisation properties as the incident sound wave is distorted by the folds of the pinna in a direction-dependent way.

There are a number of common pathologies affecting the pinna that may be discussed in an examination setting:

28.2 Protruding or Prominent Ears

This is a common occurrence although no formal figures exist for prevalence; many individuals with significant abnormalities will have no complaints while others will have significant complaints from even minor abnormalities. Like all aspects of aesthetics, much of the complaint will relate to the psychology of the patient or his/her parents.

The commonest abnormalities are a poorly developed antihelical fold or an overly developed and prominent, deep conchal bowl.

Many different surgical techniques exist to correct deformity. All rely on exposing and making alterations to the cartilage skeleton. In small babies, with modest deformity, the ‘EarBuddies’ can be used as a non-surgical alternative. A specially designed ‘scaffold’ is applied and taped to the baby’s pinna for a period of time (weeks to months) which encourages the pinna to grow and adopt the appropriate shape. In adults with poorly developed antihelical folds ‘Earfold’ nitinol implants are gaining popularity, with the advantage of being inserted under local anaesthetic.

28.3 Trauma

In such a prominent position on the side of the head, the pinna is frequently subject to both blunt and sharp trauma. With such a good blood supply, lacerations heal exceptionally well, even skin flaps which appear to have a very tenuous pedicle. Exposed or damaged cartilage should be trimmed, and the skin carefully sutured.

After blunt trauma, blood can gather between the cartilage and the perichondrium. This is therefore called a subperichondrial haematoma. As the cartilage derives its nutrient supply from the perichondrium, failure to treat this can lead to cartilage resorption and fibrosis with the consequent ‘cauliflower ear’ deformity seen frequently in boxers and rugby players.

Small haematomas may be managed by single or serial aspiration under sterile conditions. Larger and more persistent haematomas may require formal incision and drainage, followed by through and through compression sutures (classically over a suitably sized button, or semirigid dressing material) left in place for several days to prevent recurrence.

28.4 Perichondritis

This is an inflammation of the skin and perichondrium of the external ear. It is usually caused by a bacterial infection, secondary to local trauma, such as burns, bites, piercings, aspiration of haematoma or surgical incisions, but it may follow a local infection such as otitis externa. The commonest organisms are Pseudomonas aeruginosa or Staphylococcus aureus. It is distinguished from relapsing polychondritis by the absence of cartilage involvement elsewhere.

Treatment is usually with appropriate, high-dose antibiotics. Abscess formation will require incision and drainage. Resistant cases may require debridement to remove any devitalised tissues.

28.5 Skin Lesions

The skin of the pinna is not immune to any of the common dermatological problems. However, its exposed position makes it particularly prone to the effects of sun damage, and so skin cancer in the form of both basal cell and squamous cell carcinomas is common. The reader is referred to the Chapters 97 and 98 on skin cancers for further information.

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