Laboratory Studies
Culture samples may be obtained during drainage procedures.
Imaging Studies
Imaging is not indicated for routine preauricular cysts and sinuses.
Imaging is indicated in patients who present with pits or fistulas located in atypical regions, those with cartilage duplication around the external auditory canal that extends into the parotid, and those with recurrent parotid swelling. Sedation may be necessary in uncooperative or frightened children.
CT scans with contrast offer better bone definition, while MRI with contrast shows superior soft tissue delineation.
Ultrasonographic imaging may help the physician differentiate cysts, abscesses, and solid masses in this region, but it may not allow for complete analysis of the finer detail in small tracts and deeper fistulae.
Patients who have preauricular cysts or pits and a branchial cleft cyst should undergo renal ultrasonography to rule out branchio-oto-renal syndrome.
Other Tests
Audiogram is not indicated in isolated preauricular cysts, pits or tags. This was backed up by a study by Wu et al, which suggested that in children with isolated preauricular lesions but no previous otologic surgery or hearing-loss risk factors, there may be no need for audiologic assessment, apart from regular hearing screening. Nonetheless, the investigators did report that eustachian tube dysfunction appeared to be more greatly associated with such patients. The study found that of 99 pediatric patients with preauricular lesions, 12 had abnormal hearing, including five with conductive hearing loss resulting from eustachian tube dysfunction. [7]
Diagnostic Procedures
Needle aspiration may be performed in patients with infected lesions that have not responded to oral antibiotic therapy.
Histologic Findings
Findings associated with ear pits include diffuse interstitial dermatitis, abundant foreign body reaction, and ruptured follicular cyst, epidermal cyst, and epidermal sinus tract.
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Preauricular ear tag. Image courtesy of Jack Yu, MD.
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Multiple tags in a child with oculoauriculovertebral dysplasia. Note the hemifacial atrophy, retrognathia, and lower set ear. Image courtesy of Jack Yu, MD.
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Uninfected preauricular pit. Image courtesy of Ed Porubsky, MD.
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Close-up image of preauricular pit. Image courtesy of Ed Porubsky, MD.
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Infected preauricular cyst with swelling and erythema toward the cartilage of the ear.
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A preauricular sinus tract is probed with a blunt needle, and methylene blue dye is injected. Note the region in front of the pit, where previous abscess formation, spontaneous drainage, and residual scarring and granulation have occurred. This circumstance requires a more complex procedure. Removal of the entire sinus tract and the granulation disease is essential. Image courtesy of Ed Porubsky, MD.
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Preauricular sinus tract, cyst, and granulation removed. The skin was closed with slight undermining and no tension. Sutures are removed 7-10 days later.
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Keloid scar formed several months after removal of preauricular sinus tract. Intralesional steroids and close observation are indicated.
