Definition and Epidemiology

Auricular disorders are conditions that affect the external ear. The incidence and prevalence of the individual conditions vary. The auricular disorder may be a secondary issue or may be discovered during the physical examination. Auricular disorders may be benign conditions associated with other disease processes, may be related to cultural practices such as body piercing, or may be a symptom of a serious illness that requires immediate referral and treatment.

Certain disease processes are associated with specific abnormalities of the auricle. Patients with Addison disease may have calcification of the cartilage. The nodules of Hansen disease may appear on the earlobe and may initially be noticed as multiple nodules on the ear and face. Patients with chronic arthritis may have hard nodules develop in the auricle. These rheumatoid nodules are usually accompanied by similar nodules on the hands, elbows, knees, or heels. Auricular pain, erythema, and edema can be associated with relapsing polychondritis, a rheumatologic disorder that affects the cartilage of the ears, nose, and laryngobronchial system.^1,2 Relapsing polychondritis is often related to other disorders (e.g., systemic vasculitis or systemic lupus erythematosus) but can be related to nonrheumatologic disorders also (e.g., primary biliary cirrhosis, Hashimoto thyroiditis, or myelodysplasia).² Hearing loss, cardiac abnormalities, and glomerulonephritis are associated with relapsing polychondritis, which, although not common, can affect people of all ages.²

A more common auricular disorder is tophi: painless, hard or gritty, and irregular uric acid crystal deposits in the auricle. They form in relation to high uric acid levels. Pressure exerted on tophi may result in the expulsion of a white crystalline substance.

Injuries and infections are the more common auricular disorders seen in primary care offices. A hematoma of the auricle occurs in response to blood disorders or trauma. A bluish-tinged hematoma can develop in the pinna after an injury. This type of lesion may be accompanied by laceration and require incision and drainage by an ear, nose, and throat surgeon. If the lesion is not drained, the resultant deformity is commonly referred to as cauliflower ear.³

Other common auricular problems include infections and tears related to earlobe and helix piercing. Keloids, hypertrophic scar tissue that is not cosmetically acceptable but is otherwise benign, can also occur at the pierced site.⁴ Keloids occur more often in dark-skinned people.⁴ Multiple helix piercing can cause a perforation-like appearance.

Chondrodermatitis nodularis helicis is a benign, chronically inflamed lesion, usually found on the helix or antihelix.⁵ The lesion most often affects elders, men more often than women, and is painful and possibly crusting. A shave biopsy is necessary to distinguish the lesion from carcinoma.⁵ Photodynamic therapy (PDT), cryotherapy, intralesional steroid injection, electrodessication, and nodular excision are potentially successful treatment modalities.⁵

Malignant otitis externa is a severe form of otitis externa. It results in a severely edematous, erythematous, and tender auricle. It can quickly dissect through fascial planes and lead to a life-threatening infection of the head and face. It is most likely to occur in patients with diabetes and in those who have compromised immune systems. The causative organism is usually Pseudomonas aeruginosa, especially in people with diabetes.⁶

Skin cancer is probably the most common significant auricular disorder seen in primary care. Basal cell carcinoma (BCC) is the most common form of skin cancer found on the auricle and the least likely to be malignant. It is a slowly growing cancer often found in sun-exposed areas, such as the top of the auricle.⁷ BCC is found more often in older persons, in fair-skinned patients, and in patients who have a history of sun exposure. A shiny, irregular, painless lesion, this form of cancer rarely metastasizes, but in some cases BCC can be invasive and thus concerning.⁷ Squamous cell carcinoma (SCC) is also commonly found on the auricle, usually in fair-skinned patients and in patients with a history of sun exposure. The typical lesion has a raised, crusted border around a center ulcer. SCC is a more serious form of skin cancer, although still relatively benign compared with melanoma. SCC can potentially metastasize to regional lymph nodes and cause death.⁷

Pathophysiology

The auricle is the external ear structure that is composed chiefly of cartilage covered by skin. It is firm and elastic. It is divided into three parts: the top portion is the helix, the midsection is the antihelix, and the lower portion is the lobe. The function of the outer ear is to aid in receiving sound waves from the environment.