H70.813 Postauricular fistula, bilateral

Name of the Condition

• Postauricular fistula, bilateral

Summary

Postauricular fistula, bilateral, is a congenital or acquired abnormal tract connecting the skin behind both ears to deeper structures, such as the mastoid bone or middle ear. It may present as small openings, sinuses, or cysts and can be associated with chronic discharge or recurrent infections. The condition is typically benign but may require intervention if symptomatic.

Causes

Postauricular fistula is most commonly congenital, resulting from incomplete closure of the branchial cleft during embryonic development. Acquired cases may arise from chronic infections, trauma, or surgical complications. The tract forms a direct pathway between the skin and underlying structures, facilitating drainage or infection.

Risk Factors

• Congenital predisposition (family history)
• Chronic ear infections (otitis media)
• Previous ear surgery or trauma
• Immunocompromised states
• Poor hygiene or recurrent skin infections

Symptoms

• Small openings or pits behind both ears
• Persistent or intermittent discharge
• Swelling or redness around the fistula
• Pain or tenderness
• Recurrent infections or abscess formation
• Possible hearing changes if the fistula connects to the middle ear

Diagnosis

Diagnosis is typically made through physical examination, noting the characteristic openings behind both ears. Imaging studies, such as CT scans, may be used to assess the tract's depth and connection to underlying structures. Cultures of discharge can identify infectious organisms.

Treatment Options

Treatment depends on symptoms. Asymptomatic cases may require no intervention. Symptomatic cases may involve antibiotics for infections, incision and drainage of abscesses, or surgical excision of the fistula tract to prevent recurrence.

Prognosis and Follow-Up

Prognosis is generally good with appropriate treatment. Recurrence is possible if the tract is not fully excised. Follow-up may include monitoring for infection or complications, especially if surgery was performed.

Complications

• Recurrent infections or abscess formation
• Chronic discharge
• Scarring or cosmetic concerns
• Rarely, extension to deeper structures like the middle ear

Lifestyle & Prevention

Maintain good ear hygiene to reduce infection risk. Avoid trauma to the area behind the ears. Prompt treatment of ear infections may help prevent acquired cases.

When to Seek Professional Help

Seek care if there is persistent discharge, pain, swelling, recurrent infections, or signs of abscess formation. Early evaluation can prevent complications.

Tips for Medical Coders

Document the bilateral nature of the fistula clearly in the medical record. Ensure the diagnosis is supported by clinical findings, such as physical examination or imaging. Note any associated infections or interventions, as these may impact coding specificity.