Pre-auricular sinus: an uncommon presentation.

An infected pre-auricular sinus presenting as a post-auricular swelling is commonly misdiagnosed as an infected dermoid or sebaceous cyst. It may even mimic a mastoid abscess leading to further unwarranted investigations and interventions. We present a case of a 25-year-old Malay man who was initially diagnosed with recurrent infected dermoid cyst. At presentation, a right post-auricular inflamed swelling was noted with an overlying old incision and drainage scar. An auricular pit was found at the crus of helix. Using a blunt probe inserted along the sinus tract pus was drained without the need for further surgical incision. Six weeks after the acute episode, patient underwent excision of the pre-auricular sinus with no evidence of recurrence at three months follow up. Awareness by the attending physician of this 'variant type' of pre-auricular sinus at patient's first presentation may negate the need for unnecessary incision and drainage which may subsequently impact the outcome of surgical excision and reduce the risk of recurrence.