Perichondritis

Perichondritis (from the Latin perichondritis) is an inflammation of the perichondrium — a layer of dense connective tissue that envelops and nourishes the cartilage. As the cartilage lacks its own blood supply, its viability depends entirely on the integrity and function of the perichondrium.

This condition poses the greatest risk when it spreads to the auricle or the larynx. Inflammation of the perichondrium disrupts the nutritional support to the cartilage. This may lead to necrosis, liquefaction, and, consequently, irreversible ear deformity or life-threatening airway obstruction due to edema and stenosis (in the case of laryngeal involvement).

Aetiology and pathophysiology

Most commonly, perichondritis has an infectious etiology and develops when bacteria penetrate the space behind the perichondrium. Pseudomonas aeruginosa is the most frequent causative agent, followed by Staphylococcus aureus.

The primary causes include:

• Trauma: The leading factor.
  • Direct injuries such as contusions (especially accompanied by hematoma), lacerations, and insect bites.
  • Piercing of the cartilaginous portion of the auricle — one of the most common causes in young adults.
  • Burns and frostbite.
• Spread of infection: Inflammation may extend to the perichondrium from the skin in severe cases of otitis externa or furunculosis.
• Systemic diseases: In rare cases, perichondritis may be non-infectious and autoimmune in nature, as seen in relapsing polychondritis.

Impaired perichondrial integrity or a hematoma beneath it promotes bacterial proliferation. Progressive edema compresses local vessels, resulting in ischemia and, eventually, cartilage necrosis.

Clinical Significance

Clinical manifestations may vary by location but consistently include pronounced pain and swelling.

• Perichondritis of the auricle:
  • Symptoms: Acute, diffuse pain, redness, and swelling of the entire auricle. A hallmark diagnostic feature is an unaffected earlobe, which lacks cartilage and is not involved in the inflammatory process.
  • Diagnosis: Primarily clinical. Fluctuation may be noted if pus accumulates beneath the perichondrium.
  • Treatment: The condition requires systemic antibiotics, typically fluoroquinolones active against Pseudomonas aeruginosa. If an abscess develops, necrotic cartilage must be promptly incised, drained, and removed.
  • Outcome: If not treated timely, the cartilage liquefies, and the auricle becomes shriveled, resembling a “cauliflower ear”.
• Laryngeal perichondritis: The condition presents with neck pain, hoarseness, pain during swallowing, and — most critically — progressive respiratory distress (referred to as stridor), necessitating emergency hospitalization.

Differential Diagnosis

Infectious auricular perichondritis must be distinguished from erysipelas, which also presents with marked erythema and edema but typically involves the earlobe. It should also be differentiated from otitis externa and non-infectious relapsing polychondritis. In the former, inflammation is primarily confined to the external auditory canal. In the latter, bilateral, recurrent cartilage involvement is observed, affecting not only the ears but also the nose, joints, and airways.