A preauricular cyst, also called a preauricular sinus or pit, is a small tunnel-like tract that sits just in front of the ear, usually appearing as a tiny dimple or pinhole near where the outer ear meets the face. It forms before birth during ear development and is present from day one of life, though many people never realize they have one until it becomes infected or a doctor spots it during a routine exam. Most preauricular cysts cause no symptoms at all, but when they do flare up, they can become painful, swollen, and surprisingly stubborn to treat.
How Common They Are
Prevalence varies dramatically depending on where you look and who you study. In Europe and the United States, the rate runs between roughly one and nine people per thousand.1PubMed Central. Surgical treatment of recurring preauricular sinus: supra-auricular approach But those averages mask big ethnic differences. A study of over 1,100 children found that Asian children had the highest prevalence at about 6.6%, followed by African American children at 4.5%, Middle Eastern children at 3.4%, and Caucasian children at 1.2%.2PubMed. Prevalence and ethnic variation of pre-auricular sinuses in children A separate study from Singapore broke it down further among Asian subgroups, finding that Chinese subjects had a prevalence of about 1.4%, Malay subjects about 0.7%, and Indian subjects about 0.2%.3JAMA Otolaryngology–Head & Neck Surgery. Preauricular Sinus: Clinical Course and Associations The condition is present at birth, but parents often notice it only incidentally, and many adults carry one their whole lives without it ever being diagnosed.
Why They Form
During the sixth week of fetal development, the external ear starts to take shape from six small bumps of tissue called the hillocks of His, which gradually fuse together. A preauricular sinus forms when the fusion is incomplete, leaving behind a small tract or pocket lined with skin. That pocket can run deeper than it looks from the surface. Histological studies show that the tract usually sits extremely close to the ear cartilage, with more than half of specimens showing the lining of the tract less than half a millimeter from the cartilage itself.4PubMed. The histologic relationship of preauricular sinuses to auricular cartilage In many cases, the tract is essentially fused to the tissue surrounding the cartilage.5PubMed. Causes and prevention of revision surgery for preauricular sinus: A histopathological analysis That intimate relationship with the cartilage is one reason surgery can be tricky and incomplete removal is common.
Genetics and Family Patterns
Preauricular sinuses can appear randomly in a family with no history, or they can clearly run from parent to child. When inherited, the pattern follows what geneticists call incomplete autosomal dominant transmission with reduced penetrance, meaning only one copy of the gene variant is needed to cause the trait, but not everyone who carries it will actually develop a visible pit.6PubMed. The preauricular sinus: a review of its clinical presentation, treatment, and associations There is no meaningful difference in rates between males and females.7PubMed. Auricular fistula: a review of its clinical manifestations, genetics, and treatments
One interesting pattern: bilateral pits (appearing on both ears) are much more likely to be hereditary than unilateral ones. A study comparing parents and children found a strong association between a parent having bilateral sinuses and their child having them too, but no such link for unilateral sinuses.8PubMed. Analysis of incidence and genetic predisposition of preauricular sinus Between a quarter and half of all preauricular sinuses are bilateral, and bilateral involvement raises the odds that the trait was inherited rather than sporadic.9PubMed. The preauricular sinus: a review of its clinical presentation, treatment, and associations So if you notice pits in front of both ears on your child, it is worth asking whether anyone else in the family has them.
Do Preauricular Pits Mean Kidney or Hearing Problems?
This is one of the most common worries parents face when a pediatrician spots a preauricular pit on a newborn. The concern stems from branchio-oto-renal (BOR) syndrome, a genetic condition in which preauricular pits appear alongside hearing loss, ear malformations, and kidney abnormalities.10PubMed Central. Novel EYA1 Variants Causing Branchio-Oto-Renal Syndrome BOR syndrome is real and serious, but it involves multiple abnormalities at once, not just a pit by itself.
For an isolated preauricular pit with no other findings, the evidence is reassuring. A study of infants with minor ear anomalies (including preauricular pits) found the rate of kidney abnormalities was no different from the general infant population, and the authors concluded that routine kidney imaging is not warranted unless the pit is accompanied by other malformations.11PubMed Central. Renal ultrasonography not required in babies with isolated minor ear anomalies Similarly, another study comparing patients who had preauricular pits or tags with a control group found no increased rate of kidney problems or hearing impairment, again concluding that special testing is unnecessary unless there is a family history or signs of a broader syndrome.12PubMed. Isolated preauricular pits and tags: is it necessary to investigate renal abnormalities and hearing impairment?
The practical upshot: if your baby has a preauricular pit and nothing else unusual about their ears, face, or physical exam, there is no strong reason to order a kidney ultrasound or extra hearing tests beyond the standard newborn screening. If there are additional ear or facial anomalies, a family history of hearing loss, or other signs of a genetic syndrome, that changes the picture and further evaluation is appropriate.
What Happens When They Get Infected
Many people with a preauricular sinus go their entire lives without any trouble. The pit might occasionally produce a tiny amount of white or clear discharge, which is normal shedding of skin cells from the lining. The problems start when bacteria colonize the tract and cause an infection, leading to redness, swelling, pain, and sometimes a full-blown abscess in front of the ear.
The bacterial culprits are varied. One study found that Staphylococcus species were the most commonly identified pathogens, accounting for about 28% of cases, followed by Enterococcus, Streptococcus, Klebsiella, and anaerobic bacteria.13Korean Journal of Otorhinolaryngology-Head Neck Surgery. Bacterial Species Analysis and Proper Antibiotic Choices of Preauricular Fistular Abscess Another study found that most infections involved multiple organisms at once, with anaerobes, Staphylococcus aureus, and normal respiratory tract flora topping the list.14PubMed. Outcomes of single-stage excision in infected preauricular sinus: a retrospective cohort study The mixed-organism nature of these infections is worth knowing because it means a single narrow-spectrum antibiotic may not be enough.
Once a preauricular sinus gets infected for the first time, it tends to become a recurring problem. Each round of infection leaves behind scar tissue that distorts the original tract, making future infections more likely and eventual surgery more difficult.15Archives of Craniofacial Surgery. A Surgical Technique for Congenital Preauricular Sinus This cycle of infection, antibiotics, temporary relief, and re-infection is the main reason people end up in a surgeon’s office.
Managing Infections Before Surgery
The first step for an acute infection is usually oral antibiotics, sometimes combined with drainage if a fluid collection has formed. There is a genuinely useful finding here about how you drain the infection. A retrospective review compared patients who had their infected cysts treated with incision and drainage (cutting open the abscess) versus those treated more conservatively with antibiotics alone or fine-needle aspiration (using a syringe to draw out the pus). The patients who had incision and drainage had a recurrence rate of about 19%, while those managed with antibiotics or needle aspiration had a recurrence rate of only about 3%.16JAMA Otolaryngology–Head & Neck Surgery. Association of Recurrence of Infected Congenital Preauricular Cysts Following Incision and Drainage vs Fine-Needle Aspiration or Antibiotic Treatment
That is a notable difference. The thinking is that cutting open the area creates additional scarring that makes the definitive surgical excision later more complicated and less complete. In practice, most infected sinuses are initially treated with antibiotics, with needle aspiration reserved for cases where a clear fluid collection needs to be drained, and formal incision and drainage used only when gentler measures fail.17PubMed. Comprehensive management of infected preauricular sinuses/cysts The goal is to calm down the infection enough to allow definitive surgery under better conditions.
Surgical Approaches and Recurrence
Surgery is recommended for preauricular sinuses that cause repeated infections. Asymptomatic pits that never get infected generally do not need to be removed. The challenge with surgery is that the tracts can branch unpredictably beneath the skin, and missing even a small offshoot means the sinus will grow back.
The two main surgical strategies differ in how aggressively they go after the tissue around the sinus. Simple sinectomy traces and removes the visible tract itself, while the supra-auricular approach takes a wider margin of tissue, including a cuff of cartilage and skin around the base of the sinus. The results favor the wider approach convincingly. A review of over 1,200 surgically removed sinuses found a recurrence rate of about 1.2% with the supra-auricular approach compared to about 8% with sinectomy, along with fewer complications overall.18PubMed Central. Supra-auricular versus Sinusectomy Approaches for Preauricular Sinuses A separate comparative study found an even starker contrast: simple sinectomy had a 28% recurrence rate versus about 3% for the supra-auricular technique.19Indian Journal of Otology. Preauricular Sinus: A Comparative Study between Different Surgical Approaches
Some older literature reports recurrence rates for simple sinectomy as high as 22% to 42%, which is strikingly poor for a supposedly curative procedure.20Archives of Craniofacial Surgery. A Surgical Technique for Congenital Preauricular Sinus The supra-auricular approach was first proposed in 1990 and has gradually become the preferred method among ear, nose, and throat surgeons precisely because of its lower failure rate.21PubMed Central. Surgical treatment of recurring preauricular sinus: supra-auricular approach
Factors That Raise the Risk of the Sinus Coming Back
Even with good surgical technique, certain factors push recurrence rates up. One study found that performing the procedure under local anesthesia rather than general anesthesia was a significant risk factor, roughly sevenfold higher odds of recurrence.22PubMed. The preauricular sinus: factors contributing to recurrence after surgery The likely explanation is that local anesthesia makes it harder to achieve full surgical exposure and more tempting to hurry, so small branches of the tract get left behind.
A history of prior infection also matters. Repeated infections cause scarring that obscures the normal tissue planes, making it harder for the surgeon to distinguish sinus lining from surrounding scar tissue. The branching pattern of the tract itself is a core difficulty. Unlike a simple tube, many preauricular sinuses fork into multiple branches, and each terminal branch needs to be found and removed. If even one is missed, regrowth is likely.
Timing relative to active infection is another question surgeons have debated. The traditional teaching was to wait until infection fully resolved before operating. However, at least one study found no meaningful difference in outcomes between patients operated on during an active infection (after conservative measures failed) and those operated on after the infection cleared.23International Journal of Pediatric Otorhinolaryngology. Surgical results of infected preauricular sinus: No need for delay This suggests that delaying surgery for months after an infection may not always be necessary, though the decision still depends on the individual situation.
Variant Locations
The “classic” preauricular sinus opens just in front of where the upper ear meets the head, typically near the ascending part of the outer ear cartilage. But not all of them appear in that textbook spot. Some sinuses have their opening on or near the ear canal, and rarer cases show up on the earlobe itself.24PubMed. Variant Types of Preauricular Sinuses: Classifications, Clinical Presentation and Management There are even posterior variants, where the sinus tract sits behind rather than in front of the ear canal.25The Laryngoscope. The variant type of preauricular sinus: postauricular sinus
These variant locations are worth knowing about because they can be misdiagnosed. A pit on the ear canal might be mistaken for a clogged pore or a skin cyst, and a postauricular sinus can be confused with other causes of swelling behind the ear. The treatment principles are the same, but the surgical approach needs to account for the actual anatomy of the tract, which may run in unexpected directions compared to the classical type.
Art History and the Preauricular Pit
In a quirky bit of medical history, the preauricular sinus was apparently noticed by artists centuries before doctors formally described it. Paintings by the Dutch master Hieronymus Bosch, produced in the late 1400s and early 1500s, depict figures with small pits in front of the ear. The first clinical descriptions are attributed to Heusinger and Virchow in the mid-1800s, but the condition had what one review calls a history of “forgetful rediscovery,” with multiple physicians independently describing it over the decades as if it were new each time.26PubMed Central. Preauricular Sinus: A Tale of Forgetful Rediscovery The condition is common enough and mild enough that it kept slipping through the cracks of medical literature, only to be “discovered” again by the next generation.
Living with an Asymptomatic Pit
If you or your child has a preauricular pit that has never been infected, the standard recommendation is simply to leave it alone. The vast majority of pediatric ear, nose, and throat specialists surveyed on this topic would observe an asymptomatic pit without intervention. Only a small minority would recommend prophylactic removal. Keeping the area clean and dry, avoiding the temptation to squeeze or probe the opening, and watching for early signs of infection (redness, swelling, tenderness, discharge that looks cloudy or smells unusual) are the main practical steps. If an infection does develop, early treatment with antibiotics rather than aggressive drainage gives the best chance of controlling it and keeping your surgical options open should you eventually need the sinus removed. There is no evidence that a preauricular pit that never causes symptoms will cause problems later in life, so watchful waiting is not just the easy path; it is the medically sound one.