Preauricular pit

Preauricular Pit

A preauricular pit—also known as a preauricular sinus or cyst—is a common congenital malformation characterized by a small pit or opening in the skin near the external ear, specifically located just anterior to the ascending limb of the helix. While the exact cause of preauricular pits is not fully understood, they are believed to arise from the incomplete fusion of the six hillocks of His, which contribute to the formation of the external ear during embryonic development.

Etiology and Genetics

The development of preauricular pits is thought to be influenced by genetic factors, as they can occur in families with a history of this condition, suggesting a possible autosomal dominant inheritance pattern with incomplete penetrance. However, sporadic cases are also common. The condition has been associated with various genetic syndromes, including Branchio-oto-renal syndrome and Treacher Collins syndrome, although most individuals with preauricular pits are otherwise healthy and have no other anomalies.

Clinical Presentation

Preauricular pits are typically present at birth and can occur on one or both sides of the head. They are usually asymptomatic but can become infected, leading to the formation of an abscess or cyst. In such cases, symptoms may include pain, swelling, and discharge from the pit. Chronic infections can lead to the formation of a sinus tract or cystic enlargement, necessitating medical intervention.

Diagnosis

The diagnosis of a preauricular pit is primarily clinical, based on the characteristic appearance and location of the pit. Imaging studies, such as ultrasound or MRI, may be necessary if there is concern about an underlying cyst or sinus tract, especially in cases of recurrent infection.

Treatment

Treatment of a preauricular pit is not necessary unless it becomes infected or symptomatic. In cases of infection, initial management typically involves antibiotics. If infections are recurrent or if there is a cystic enlargement, surgical excision of the pit and any associated tract or cyst may be recommended to prevent further complications.

Prognosis

The prognosis for individuals with a preauricular pit is generally excellent. Surgical intervention, when required, is usually successful in preventing recurrent infections and other complications.

Epidemiology

Preauricular pits are relatively common, with reported incidences varying widely among different populations and ethnic groups. They are more frequently observed in certain populations, such as those of African or Asian descent, and are slightly more common on the right side. The condition can occur in isolation or as part of a syndrome involving other anomalies.