Pinna Perichondritis

Excerpt

Pinna perichondritis is the inflammation of the perichondrial layer surrounding the auricular cartilage. This condition is often a more severe infection than, but frequently mistaken for, pinna cellulitis, which shares its risk factors. Penetrating ear trauma, such as transcartilaginous ear piercing, is the most common cause of this disease. Nonmedical personnel perform most ear piercings, with infection ensuing if sterile conditions are not maintained.

Abscesses arise from neglected infection, resulting in perichondrial detachment that devascularizes the underlying cartilage. The condition may lead to cartilage necrosis and pinna shape alteration. Inflammation may develop from blood collecting within the space between the perichondrium and cartilage and within the cartilaginous layer. Cauliflower ear deformity is a potential complication arising from inflammatory fibrocartilaginous proliferation (see Image. Severe Cauliflower Ear Deformity). Bacterial perichondritis can also progress to a severe soft tissue or systemic infection if left untreated.

Auricle Histology

The auricle, or external ear pinna, is composed of elastic cartilage encased in a dense perichondrium containing elastic fibers. Auricular skin hosts sparse hairs, sebaceous glands, and eccrine sweat glands. The auricle's skin has keratinized stratified squamous epithelium that tightly adheres to the perichondrium, except in the posterior aspect where fatty subcutaneous and skeletal muscle layers exist.

The perichondrium serves crucial functions. This fibrous covering provides structural support to the auricle's elastic cartilage, maintaining ear shape and integrity. The pinna's cartilage is avascular and thus depends on the highly vascularized perichondrium for oxygen and nutritional support. Chondroblasts within the inner perichondrium facilitate the repair and growth of cartilage tissue. This fibrous layer also acts as an attachment site for the overlying skin. Perichondrial pathology, such as inflammation or infection, can lead to complications like auricular deformity or abscess formation, highlighting the importance of maintaining the integrity of this fibrous layer.