eMedicine Specialties > Dermatology > Pediatric Diseases

Preauricular Sinuses

Author: Noah S Scheinfeld, MD, JD, FAAD, Assistant Clinical Professor, Department of Dermatology, Columbia University; Consulting Staff, Department of Dermatology, St Luke's Roosevelt Hospital Center, Beth Israel Medical Center, New York Eye and Ear Infirmary; Private Practice
Coauthor(s): Valerie Nozad, DO, Staff Physician, Beth Israel Medical Center, Department of Internal Medicine, University Hospital for the Albert Einstein College of Medicine; Jeffrey Weinberg, MD, Director, Clinical Research Center, Department of Dermatology, St Luke's; Assistant Clinical Professor, Department of Dermatology, Columbia University College
Contributor Information and Disclosures

Updated: Mar 18, 2008

Introduction

Background

Preauricular sinuses are common congenital malformations first described by Heusinger in 1864. They 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, they 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, they 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 like to be hereditary. In unilateral cases, the left side is more commonly affected.

A few resources that may be helpful include the eMedicine article Preauricular Cysts, Pits, and Fissures, the Medscape Otitis Media Resource Center, and the Medscape CME courses Diagnostic Methods to Treat Ear Pain in Primary Care Setting and Antibiotics Not Recommended to Prevent Middle Ear Effusion in Children.

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 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 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 is estimated to be 4-10%.

Mortality/Morbidity

• Preauricular sinuses have no associated mortality.
• Morbidity 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 in African Americans and Asians is 1-10%.

Sex

Both men and women are affected equally.

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 this malformation 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 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 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 may develop scarring and disfigurement.
• Infants of diabetic mothers are at increased risk for the oculo-auriculo-vertebral sequence, which includes sinuses.¹

Physical

The preauricular sinus usually presents as a small dell adjacent to the anterior margin of the ascending limb of the helix. 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 Lissner² 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,³ 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, 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.

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