A sinus infection can affect only one side of your face. While many sinus infections, such as those caused by viruses like the common cold, often affect both sides, specific factors can lead to an infection localized to a single sinus cavity. This unilateral presentation is commonly observed in bacterial sinus infections.
Understanding Unilateral Sinusitis
The human head contains several pairs of air-filled paranasal sinuses. These include the frontal sinuses above the eyes, the ethmoid and sphenoid sinuses between and behind the eyes, and the largest, the maxillary sinuses, under the eyes and behind the cheeks. Each sinus is a distinct compartment. An infection in one cavity does not automatically spread to others. This anatomical separation explains why inflammation and infection can be confined to one side of the face.
Specific Causes of One-Sided Sinus Infections
Several factors can lead to a one-sided sinus infection. Infections originating from the upper teeth are a common cause, particularly impacting the maxillary sinus due to its close proximity to tooth roots. Dental issues like periapical abscesses, gum disease, or procedures such as extractions can allow bacteria to spread directly into the sinus, accounting for up to 30% of unilateral maxillary sinusitis cases. These infections are often resistant to initial antibiotic treatments because they involve multiple types of bacteria, particularly anaerobic ones.
Anatomical variations in nasal passages can predispose individuals to one-sided infections by obstructing drainage. A deviated septum, where the wall separating the nostrils shifts to one side, can narrow a nasal passage and impede mucus flow. Similarly, an enlarged concha bullosa (an air-filled pocket within a nasal turbinate) can block a single sinus opening, leading to mucus buildup and infection.
Fungal infections are another cause of unilateral sinusitis, often localizing to a single sinus cavity. A “fungal ball” (mycetoma) forms when inhaled fungal spores clump in a sinus, most commonly the maxillary. These typically affect one side and may not cause symptoms until they obstruct the sinus. Allergic fungal sinusitis, another type, is an allergic reaction to fungi that can also present unilaterally.
Rarely, a foreign body lodged in the nasal cavity or sinus can cause a localized infection. This is more common in children, but can occur in adults (e.g., with dental packing material). Such obstructions trap mucus and lead to bacterial growth, often resulting in foul-smelling, one-sided nasal discharge. Tumors or cysts, though less common, can also block a single sinus’s drainage pathway, creating an environment for infection.
Recognizing Symptoms of Unilateral Sinusitis
Symptoms of a one-sided sinus infection often reflect its localized nature. Individuals typically experience facial pain or pressure predominantly on one side, perhaps around an eye, cheek, or forehead. This discomfort can be throbbing and may worsen when bending over or moving the head suddenly.
Unilateral nasal congestion or discharge is another common indicator. The affected nostril may produce thick, discolored mucus (often yellow or green), differentiating it from generalized allergies or colds. Pain in the upper teeth on the same side is also frequently reported, especially when the maxillary sinus is involved due to its proximity to dental roots. A headache predominantly on one side, or a sense of fullness and pressure in one ear, can also indicate a unilateral sinus infection.
Diagnosis and Treatment Approaches
Diagnosing a one-sided sinus infection begins with a medical history and physical examination. A healthcare provider will ask about symptoms and may palpate facial areas over the sinuses for tenderness. They may also use a light to examine nasal passages for inflammation or blockages.
Imaging studies are crucial for confirming diagnosis and identifying the underlying cause. A computed tomography (CT) scan of the sinuses provides detailed images, revealing fluid buildup, mucosal thickening, anatomical abnormalities (like a deviated septum or concha bullosa), foreign bodies, or the extent of fungal infection or tumor. Nasal endoscopy, using a thin, lighted tube with a camera, allows direct visualization of nasal passages and sinus openings, helping identify blockages or infection sources.
Treatment varies depending on the identified cause. For bacterial infections, antibiotics are prescribed. Fungal infections, especially fungal balls, often require antifungal medications, though surgical removal of the fungal mass is frequently necessary. Symptomatic relief can be achieved with decongestants (to reduce swelling), nasal sprays (to improve drainage), and pain relievers.
When anatomical issues, foreign bodies, or persistent blockages are the root cause, surgical intervention may be recommended. Functional Endoscopic Sinus Surgery (FESS) uses an endoscope to open sinuses, remove diseased tissue, correct structural problems, or extract foreign objects. This procedure aims to restore normal sinus drainage and ventilation. Seek medical attention if symptoms are severe, worsening, or persist beyond a typical cold, especially if localized to one side, as this could indicate a condition requiring specific medical management.