Pinna Perichondritis

Etiology

Pinna perichondritis has various triggers, but penetrating auricular cartilage trauma is the most commonly cited in the literature.[3][4] The increasing popularity of transcartilaginous ear piercings has been implicated as the cause of the rising perichondritis cases in the past decade. Transcartilaginous ear piercings carry a greater risk of infection and abscess formation than lobule piercings.[5] The infection risk increases after exposing the wound to freshwater or hot tubs immediately after the piercing.[6] Less common pinna perichondritis causes include untreated middle or external ear infections that spread to the pinna and cartilage, iatrogenic injury, immunosuppression, and other forms of minor trauma, such as ear scratching, insect bites, and acupuncture. A significant proportion of patients with this condition have no identifiable cause.

The most common organism isolated in pinna perichondritis cases is Pseudomonas aeruginosa, which has a predilection for infecting damaged cartilage. This bacterial species is responsible for up to 100% of piercing-related infections and is often associated with ear perichondrial abscess formation.[7] Other causative organisms include Staphylococcus aureus, Escherichia coli, and Proteus spp, with Staphylococcus being the most common organism when abscess does not form.[8] Fungal infection has been occasionally reported and may be linked to perioperative prophylactic antibiotic administration for otologic surgery.[9] Perichondritis may also arise from viral infections like herpes zoster and monkeypox that create skin vesicular lesions, which establish a bacterial entry route into the deep pinna structures.[10] Less common etiologies include retained ear wick after placement for otitis externa and recurrent infection of a congenital intraauricular sinus tract.

Epidemiology

Pinna perichondritis is uncommon. The condition's incidence is unknown, though it has been reported that the number of cases doubled between 1990 and 1998 in England. This increase seems to parallel the rising popularity of cartilaginous ear piercings among adolescents and young adults.[11] A 2015 systematic review revealed that women are more than 7 times as likely as men to develop complications from transcartilaginous ear piercing. This outcome is attributed to the relative frequency of ear piercings between sexes rather than a physiological difference. The mean age of patients developing complications from transcartilaginous ear piercing is 19 years.

Another study revealed that treatment delay of more than 5 days significantly increased the likelihood of hospitalization, as did Pseudomonas aeruginosa compared to Staphylococcus aureus infection. Pseudomonas accounted for 87% of the cases in the study. Perichondritis after scapha piercing was associated with long-term ear deformity in 100% of patients, contrasting with the 43% occurrence rate in patients with helical piercings (see Image. Auricle Surface Anatomy).

Pathophysiology

Trauma can cause cartilage microfractures, separating the perichondrium from the underlying cartilage. Cartilaginous tissue is subsequently devascularized, leading to necrosis and space formation for blood or pus accumulation.[11] The cartilage's scanty blood supply makes it especially susceptible to infection even with careful implementation of the aseptic technique during ear piercing.[12] Chondritic infection can spread to the perichondrium and overlying skin, resulting in perichondritis, cellulitis, and abscess formation. 

If neglected, significant necrosis and hematoma can arise and produce cosmetic deformity. Blood collection in the cartilage fracture lines can cause an inflammatory reaction, inducing fibrocartilage deposition and the development of the auricular deformity colloquially called the "cauliflower ear."[13][14] 

Histopathology

Van Wijk et al's 2008 cadaveric study revealed that ear-piercing techniques caused perichondrial tearing from the cartilage, leading to microfractures, blood and pus accumulation, and abscess formation. Greater injury occurred at the exit sites, similar to a gunshot wound, with no significant disparity between hypodermic needles and piercing guns observed. However, cadaveric models may not correlate with in vivo tissue injury patterns with 100% accuracy.[15]

History and Physical

History

Pinna perichondritis is a clinical diagnosis. Therefore, taking a focused history and performing a thorough physical examination are essential. Individuals with pinna perichondritis often present with significant pain, swelling, and erythema localized to the external ear, with purulent discharge in severe cases. Fever and cervical node swelling may occur if the infection spreads beyond the outer ear. A recent history of ear or lateral facial trauma may be elicited, eg, from piercing, acupuncture, abrasions, burns, lacerations, or insect bites. Clinicians should ask about relevant symptoms such as hearing loss, otorrhea, and cranial nerve abnormalities, which may indicate a different diagnosis, such as otitis externa, otitis media, or mastoiditis. Particular attention should be paid to comorbidities in the patient’s past medical history, such as diabetes and immunosuppression, which can increase the likelihood of infections.

Physical Examination

Physical examination should include a comprehensive ear exam with inspection, palpation, and otoscopy. Auricular perichondritis typically presents with an erythematous, swollen, hot, and tender pinna (see Image. Pinna Perichondritis). Examination may reveal soft tissue abscess or necrosis. Palpation typically demonstrates a tender pinna. The mastoid process and preauricular and postauricular regions should also be examined for tenderness. The lobule is classically spared in perichondritis and chondritis, differentiating these conditions from pinna cellulitis, which tends to involve the entire auricle.[16][17] Notably, perichondritis and cellulitis are caused by different microbiological agents. Any area affected by pinna cellulitis should be marked at presentation to monitor treatment response.

Systemic symptoms, such as pyrexia or an erythematous extension beyond the pinna, suggest that the infection has spread beyond the external ear. Careful otoscopy should be performed, with the unaffected ear examined first. The clinician should look for external ear canal debris, discharge, erythema, or swelling. These findings indicate otitis externa, primarily treated with external auditory canal debridement, topical antibiotics, and dry ear precautions. The tympanic membrane should also be assessed for an air-fluid level or perforation that can point to middle ear pathology. A cranial nerve assessment and cervical lymph node evaluation should be performed as indicated.

Relapsing polychondritis should be entertained if a patient presents with nasal, joint, tracheobronchial, and bilateral pinna inflammation. The syndrome is an autoimmune condition typically treated with oral steroids.[18]

Evaluation

Routine blood tests are not usually indicated in simple pinna perichondritis. However, substantial edema or erythema of the surrounding area, an abscess, or necrosis warrants laboratory testing, including complete blood count, basic metabolic panel (or complete, depending on clinical presentation), C-reactive protein, blood cultures, and coagulation profile. These tests should be included as part of a sepsis screen in an unstable patient. Culture swabs should be taken from the affected area and any discharge present or obtained from incision and drainage. Imaging is not indicated unless intracranial pathologies, such as malignant otitis externa, are suspected.

Treatment / Management

Antibiotic therapy is the treatment mainstay for pinna perichondritis. Management depends on the presence of an abscess and its severity. Outpatient oral fluoroquinolones often suffice for cases without abscesses. Levofloxacin is an example that has antistaphylococcal and antipseudomonal activity. The presence of an abscess requires both surgical drainage and fluoroquinolone treatment. Abscesses are approached similarly to an auricular hematoma, with incision, irrigation, a pressure dressing, and potentially drain placement.[19]

Patients with abscesses are more likely to have Pseudomonal infections and require hospitalization for intravenous antibiotic administration. Preferred options include third and fourth-generation cephalosporins, aminoglycosides, and fluoroquinolones. However, fluoroquinolones have been historically avoided in the pediatric population due to the risk of developing arthralgia and tendon rupture. However, a 2011 meta-analysis of fluoroquinolone use in children demonstrated a low incidence of musculoskeletal side effects, which all resolved on medication withdrawal. No studies showed associated growth disturbances, suggesting that a short fluoroquinolone course is safe for pediatric patients.[20] Pinna perichondritis is painful. Thus, adequate analgesia should also be provided.(A1)

Incision and drainage of auricular abscesses and seromas may be performed with minimal scarring and cosmetic impact. A curvilinear incision along the medial helical aspect of the anterior pinna is typically adequate for draining abscesses, which typically involve the scaphoid fossa. This approach allows effective pus drainage without creating conspicuous scars (see Image. Incision and Drainage of an Auricular Hematoma). An incision may also be made with similarly unobtrusive scarring at the conchal bowl's outer edge along the medial antihelical margin. Pressure should be applied once the fluid collection is cultured and drained to prevent reaccumulation, similar to auricular hematoma management.

The cartilage window technique has been employed for subperichondrial abscesses, but through-and-through mattress suturing appears to be more effective for preventing pus reaccumulation. The cartilage window technique involves making a skin incision as previously described and then removing a roughly 1 x 1 cm cartilage piece with its overlying perichondrium from the area of the fluid collection while preserving the underlying perichondrium. The skin can then be primarily closed or left to granulate by secondary intention with or without drain or packing placement.[21] Mattress suturing is substantially less involved and requires nothing more than running a through-and-through stitch back and forth across the affected area to keep the skin and perichondrium apposed to the underlying cartilage. An absorbable suture, such as a 4-0 plain gut on a small Keith needle, is typically used. Cotton dental rolls or clothing buttons may also be employed to pressure the ear, typically held in place by mattress sutures.[22][23](B2)

Cases unrelated to auricular trauma but arising from conditions like otitis externa, herpes zoster oticus, and relapsing polychondritis require treatment of the primary pathology.

Auricular deformity may develop in some patients despite appropriate perichondritis management. Reconstruction, if required, should be delayed 6 to 12 months after infection resolution to improve surgical exposure and optimize healing.[24] The reconstruction type employed depends on the deformity observed, but treatment is generally performed according to cauliflower ear management principles (see Image. Surgical Repair of Cauliflower Ear).[25]

Ideally, the native cartilage is unfurled and sutured into place. However, auricles that have lost normal contour may require grafting using contralateral conchal cartilage—with costal cartilage being an acceptable alternative—to restore normal height and projection. Severe deformities may warrant replacing most or all of the auricular cartilage with a costal cartilage framework. Postauricular flaps may be used if additional skin is required due to soft tissue contraction.[26][27]

Differential Diagnosis

Clinicians should be aware of the various pathologies that can cause a painful, inflamed pinna. The differential diagnosis should thus include the following:

• Auricular abscess
• Auricular cellulitis
• Auricular hematoma
• Dermatological conditions affecting the ear, eg, eczema, psoriasis, and contact reaction
• Erysipelas
• Hemangioma
• Herpes zoster oticus
• Leprosy
• Lymphoma
• Monkeypox
• Otitis externa
• Relapsing polychondritis
• Skin cancer
• Sunburn

A thorough clinical and diagnostic evaluation can differentiate these conditions from pinna perichondritis and help determine the appropriate management strategy.

Prognosis

The symptoms of pinna perichondritis should subside in 2 to 3 days with prompt diagnosis and antibiotic therapy, though pain and tenderness can persist for a month or longer. The condition may cause a cosmetic deformity, depending on the severity of the infection and cartilaginous damage. However, Sosin et al's 2015 systematic review reveals that the presence of an abscess at presentation does not significantly alter the outcomes.

Complications

Perichondritis may lead to cartilage necrosis, minor cosmetic deformity, or a cauliflower ear if left untreated. Scapha perichondritis increases ear deformity risk compared to helical involvement and is more likely when the infection is left untreated for more than 5 days. The infection may spread within the cartilage in some cases, although bacterial chondritis is managed similarly to perichondritis.[28] The infection can also spread beyond the pinna and cause systemic illness due to toxic shock syndrome or endocarditis, necessitating intravenous antibiotics and hospital admission.[29][30]