Introduction
Background
Preauricular sinuses are common congenital malformations first described by Heusinger in 1864. Preauricular sinuses are frequently noted on routine physical examination as small dells adjacent to the external ear, usually at the anterior margin of the ascending limb of the helix. However, preauricular sinuses have been reported to occur along the lateral surface of the helicine crus and the superior posterior margin of the helix, the tragus, or the lobule. Anatomically, preauricular sinuses are lateral and superior to the facial nerve and the parotid gland.
Preauricular sinuses are inherited in an incomplete autosomal dominant pattern, with reduced penetrance and variable power of expression. They can arise spontaneously. The sinus may be bilateral in 25-50% of cases, and bilateral sinuses are more likely to be hereditary.1 In unilateral cases, the left side is more commonly affected.
Also see the related eMedicine article Preauricular Cysts, Pits, and Fissures.
Pathophysiology
During embryogenesis, the auricle arises from the first and second branchial arches during the sixth week of gestation. Branchial arches are mesodermal structures covered by ectoderm and lined with endoderm. These arches are separated from each other by ectodermal branchial clefts externally and by endodermal pharyngeal pouches internally. The first and second branchial arches each give rise to 3 hillocks; these structures are called the hillocks of His. Three hillocks arise from the caudal border of the first branchial arch, and 3 arise from the cephalic border of the second branchial arch. These hillocks should unite during the next few weeks of embryogenesis. Preauricular sinuses are thought to occur as a result of incomplete fusion of these hillocks.
Preauricular sinuses are usually narrow, they vary in length (usually they are short), and their orifices are usually minute. They may arborize and follow a tortuous course in the immediate vicinity of the external ear. The preauricular sinuses are usually found lateral, superior, and posterior to the facial nerve and the parotid gland. In almost all cases, the duct connects to the perichondrium of the auricular cartilage. They can extend into the parotid gland.
Frequency
United States
In one study, the incidence of preauricular sinuses in the United States is estimated to be 0-0.9% and the incidence in New York State is estimated to be 0.23%.
International
In Taiwan, the incidence of preauricular sinuses is estimated to be 1.6-2.5%; in Scotland, 0.06%; and in Hungary, 0.47%. In some parts of Asia and Africa, the incidence of preauricular sinuses is estimated to be 4-10%.
Mortality/Morbidity
- Preauricular sinuses have no associated mortality.
- Morbidity associated with preauricular sinuses includes recurrent infections at the site, ulceration, scarring, pyoderma, and facial cellulitis. Specifically, the following conditions may occur: abscesses at and anterior to the involved ear, chronic and recurrent drainage from sinus orifices, malar ulceration, otitis externa, and unilateral facial cellulitis.
- Surgical treatment has its own associated morbidity, with the possibility of postoperative recurrence.
Race
The incidence of preauricular sinuses in whites is 0.0-0.6%, and the incidence of preauricular sinuses in African Americans and Asians is 1-10%.
Sex
Both men and women are affected equally by preauricular sinuses.
Age
Preauricular sinuses arise in the antenatal period and are usually present at birth, but they can become apparent later in life.
Clinical
History
- Most people with preauricular sinuses are asymptomatic. Only one third of persons are aware of their malformations. In one study of 31 patients, once the lesions became apparent, about 9.2 years (on average) passed before they sought medical care.
- Some patients with preauricular sinuses present with chronic intermittent drainage of purulent material from the opening. Draining sinuses are prone to infection. Once infected, these sinuses rarely remain asymptomatic, often developing recurrent acute exacerbations.
- Patients with preauricular sinuses may present with facial cellulitis or ulcerations located anterior to the ear. These ulcerations are often treated without recognition of the primary source, and the preauricular sinus remains unnoticed.
- Subsequent to infection, a patient with preauricular sinuses may develop scarring and disfigurement.
- Infants of diabetic mothers are at increased risk for the oculo-auriculo-vertebral sequence, which includes sinuses.2
Physical
The preauricular sinus usually presents as a small dell adjacent to the anterior margin of the ascending limb of the helix, as noted in the image below.
Small dell adjacent to the ear demonstrates the preauricular sinus.
Unless they are actively infected or have previously been infected with subsequent scarring, they are only small openings in the external ear. If associated conditions are present, one might see external ear anomalies, such as flop ears. Physical examination may reveal associated branchiogenic fistulas and/or hearing loss.
In 2006, Saltzmann and Lissner3 reported an unusual case of familial punctal atresia with apparent genetic linkage to bilateral preauricular sinuses that lacked any comorbid syndromic features, which is usually not the case.
Choi et al,4 in 2007, noted that what is termed the preauricular sinus can occur in the postauricular area. Sinuses occurring in the postauricular areas seem to have a lower rate of recurrence after surgery (0%) than those in the preauricular area (2.2%).
- Associated conditions
- Conditions associated with preauricular sinuses include subcondylar impaction of a third molar, renal malformations,5 hearing loss, branchiogenic fistulas, commissural lip pits (3.8% of patients with these have preauricular sinuses), and external ear anomalies; however, these conditions rarely occur.
- Cleft palate, spina bifida, imperforate anus, renal hypoplasia or renal agenesis, reduplication of the duodenum, undescended testes, and umbilical hernias are reported associations.
- Preauricular sinuses are involved in the following syndromes: Treacher Collins syndrome; branchio-oto-renal (BOR) syndrome; hemifacial microsomia syndrome; a syndrome consisting of facial steatocystoma multiplex associated with pilar cysts and bilateral preauricular sinuses; and a syndrome that includes preauricular sinuses, conductive deafness, commissural lip pits, and external ear abnormalities. BOR syndrome consists of conductive, sensorineural, or mixed hearing loss; preauricular pits; structural defects of the outer, middle, or inner ear; renal anomalies; lateral cervical fistulas, cysts, or sinuses; and/or nasolacrimal duct stenosis or fistulas. Hemifacial microsomia syndrome can include preauricular sinuses, facial nerve palsy, sensorineural hearing loss, microtia or anotia, cervical appendages containing cartilage, and other defects.
- Associated facial pathology
- Preauricular sinuses can be associated with facial pathology. In one case, a preauricular sinus associated with a congential cholesteatoma resulted in a facial palsy by impinging on the facial nerves.
- Wound infections after rhytidectomy have also been associated.
- Calculi can develop in the preauricular sinuses, resulting in infection.
Causes
Preauricular sinuses are malformations that result from incomplete fusion of 2 of the 6 hillocks that arise from the first and second branchial arches.
More on Preauricular Sinuses |
 Overview: Preauricular Sinuses |
| Differential Diagnoses & Workup: Preauricular Sinuses |
| Treatment & Medication: Preauricular Sinuses |
| Follow-up: Preauricular Sinuses |
| Multimedia: Preauricular Sinuses |
| References |
| Next Page » |
References
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Wang R, Martinez-Frias ML, Graham JM Jr. Infants of diabetic mothers are at increased risk for the oculo-auriculo-vertebral sequence: A case-based and case-control approach. J Pediatr. Nov 2002;141(5):611-7. [Medline].
Saltzmann RM, Lissner GS. Familial absence of lacrimal puncta associated with preauricular sinuses. J Pediatr Ophthalmol Strabismus. Jul-Aug 2006;43(4):233-5. [Medline].
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Baatenburg de Jong RJ. A new surgical technique for treatment of preauricular sinus. Surgery. May 2005;137(5):567-70. [Medline].
Yeo SW, Jun BC, Park SN, et al. The preauricular sinus: factors contributing to recurrence after surgery. Am J Otolaryngol. Nov-Dec 2006;27(6):396-400. [Medline].
Tang IP, Shashinder S, Kuljit S, Gopala KG. Outcome of patients presenting with preauricular sinus in a tertiary centre--a five year experience. Med J Malaysia. Mar 2007;62(1):53-5. [Medline].
Dickson JM, Riding KH, Ludemann JP. Utility and safety of methylene blue demarcation of preauricular sinuses and branchial sinuses and fistulae in children. J Otolaryngol Head Neck Surg. Apr 2009;38(2):302-10. [Medline].
Coatesworth AP, Patmore H, Jose J. Management of an infected preauricular sinus, using a lacrimal probe. J Laryngol Otol. Dec 2003;117(12):983-4. [Medline].
Winkler AA, Stallmeyer MJ, Le TT. Report of a scalp arteriovenous malformation spontaneously hemorrhaging into a preauricular sinus. Ear Nose Throat J. Feb 2009;88(2):E17-20. [Medline].
Further Reading
Keywords
preauricular sinuses, preauricular sinus, congenital aural sinuses, preauricular fistula, congenital preauricular cysts, congenital ear pit, preauricular pits
