A sinus tract is a narrow channel that forms within the body, typically connecting an area of infection or inflammation to a skin or mucous surface. This abnormal passageway allows for the drainage of fluid, such as pus, from an underlying abscess or infected site. It is important to distinguish a sinus tract from the air-filled nasal sinuses, as the term “sinus” in this context refers to a pathological channel, not the anatomical cavities in the skull.
Understanding a Sinus Track
A sinus tract presents as a tunnel-like structure, often lined with granulation tissue, serving as a pathway for inflammatory exudates to exit the body. This channel extends from a deep-seated infection to an opening on the skin or a mucous membrane. Common locations include areas around teeth from dental abscesses, near hair follicles in skin infections, or at sites of previous surgical procedures.
A sinus tract differs from a fistula. A fistula creates an abnormal connection between two epithelialized surfaces or hollow organs, or between a hollow organ and the skin. A sinus tract, however, connects an infected cavity or abscess to a single epithelial surface, such as the skin. The presence of a sinus tract often provides a release for pressure from an underlying infection, which can sometimes make the original source of infection less painful or even asymptomatic.
Common Causes of Sinus Tracks
A sinus tract often results from an underlying infection forming an abscess. Dental abscesses are a frequent cause, where bacteria infect a tooth’s pulp and spread to the surrounding bone, creating a pus-filled pocket that seeks an exit. Skin infections, such as those from infected hair follicles or sebaceous cysts, can also form a draining sinus tract if not contained.
Foreign bodies lodged in tissues, like splinters or non-absorbable suture material, can act as persistent irritants, leading to chronic inflammation and sinus tract formation. Complications following surgical procedures, including inadequate drainage or retained necrotic tissue, may also contribute to their development. Chronic inflammatory conditions, where ongoing inflammation prevents proper healing, can also lead to persistent draining channels.
Recognizing the Signs and Symptoms
Recognizing a sinus tract involves observing changes on the skin or mucous membranes. A common indication is a persistent opening or small hole on the surface that discharges fluid periodically or continuously. This discharge can vary, ranging from thick pus to clear or bloody fluid, and sometimes carries a foul odor.
Localized swelling and tenderness around the affected area are common symptoms. The skin overlying the tract may appear red or inflamed. While the underlying infection can sometimes be asymptomatic due to drainage, pain may be present, especially if the tract becomes blocked or the infection flares up.
Diagnosis and Treatment Approaches
Diagnosing a sinus tract typically begins with a thorough physical examination, inspecting the affected area and probing the opening to assess its depth and direction. Imaging studies are often used to visualize the tract’s extent and identify the underlying source of infection. X-rays can reveal bone involvement, such as in cases of osteomyelitis, while detailed imaging like CT scans or MRIs provide a view of soft tissue involvement and abscesses.
A fistulogram involves injecting a radiopaque contrast material into the tract and taking X-ray images to precisely map its pathway and any branching extensions. The primary goal of treatment is to address the root cause of the sinus tract. This often involves drainage of any underlying abscesses to remove accumulated pus and relieve pressure.
Antibiotics are commonly prescribed to manage the bacterial infection. If a foreign body is maintaining the tract, its surgical removal is necessary. When the tract is chronic or does not heal with conservative measures, surgical excision of the entire sinus tract may be performed to ensure complete eradication and prevent recurrence.