A preauricular sinus or cyst a common congenital malformation resulting from a developmental defect of the first and second pharyngeal arches. It is estimated to occur in about 1-5% of the population. It can occur on one or both sides. In rare circumstances, similar-looking pits around the ear may be part of a genetic condition where other organs may be affected such as branchio-oto-renal syndrome.
A preauricular sinus usually appears as a pit or dimple in front of the auricle of the ear. Sometimes, it may form a cyst due to blockage of the sinus and accumulation of debris. Most people with preauricular sinuses do not experience any problems. However, they may develop symptoms such as thick or foul-smelling discharge, swelling or even infection with the production of pus.
Preauricular sinuses that are symptomatic require treatment. Definitive treatment involves complete excision of the sinus or cyst to minimise the risk of recurrence. If, however, the preauricular sinus is infected, initial treatment of the infection with antibiotics and drainage of pus (where present) may first be required before definitive excision is performed.