A fungal sinus infection, or mycotic sinusitis, is an inflammation of the paranasal sinuses caused by fungal elements. This condition is distinct from common viral or bacterial sinusitis, requiring the actual presence of fungi within the sinus cavities for diagnosis. Symptoms vary widely and are categorized primarily as non-invasive (fungus remains on the surface) or invasive (fungus penetrates and destroys tissue). Understanding these categories is important because they have different prognoses and require unique treatment approaches.
Symptoms of Non-Invasive Fungal Infections
Non-invasive fungal sinusitis is the most common type, generally affecting individuals with healthy immune systems. These conditions, including Allergic Fungal Rhinosinusitis (AFRS) and Fungus Ball (Mycetoma), involve a localized fungal accumulation or reaction. Symptoms often resemble chronic bacterial sinusitis, persisting for months and typically including persistent nasal congestion and obstruction.
In Allergic Fungal Rhinosinusitis, symptoms result from an allergic reaction to the fungi. This often leads to the formation of nasal polyps and thick, tenacious discharge. This discharge, known as “allergic mucin,” is sticky and may appear green, brown, or black due to fungal elements. Patients frequently experience mild facial pressure or headache, along with a reduced or total loss of the sense of smell (anosmia).
Fungus Ball (mycetoma) is a dense clump of fungal hyphae forming a mass, usually within a single sinus cavity. Symptoms are frequently unilateral, affecting only one side of the face. They are caused by the physical blockage of the sinus drainage pathway, resulting in a dull pressure that is difficult to relieve.
Identifying Acute Invasive Fungal Sinusitis
Acute invasive fungal sinusitis is a rapidly progressing, life-threatening condition requiring immediate medical intervention. This form is typically seen in severely immunocompromised individuals, such as those with uncontrolled diabetes or hematologic malignancies. The infection is highly aggressive because the fungi invade and destroy blood vessel walls, leading to tissue death (necrosis) in the nose and sinuses.
Symptoms escalate quickly, often over hours or days, and include a rapid onset of high fever and severe, debilitating facial pain. A characteristic sign is the appearance of a black, necrotic tissue crust, known as an eschar, found on the nasal septum or hard palate. As the infection spreads beyond the sinuses, patients may develop eye-related symptoms. These include proptosis (protruding eyeball), swelling around the eyes, or diplopia (double vision), due to the fungus invading the orbit.
Neurological symptoms quickly follow, such as numbness over the cheek (paresthesia) or changes in mental status. This reflects the spread of infection toward the brain. This rapid destruction and vascular spread distinguish this form as a medical emergency with a high risk of mortality.
Recognizing Chronic Invasive Fungal Infections
Chronic invasive fungal sinusitis is generally restricted to individuals with compromised immunity, but its progression is significantly slower than the acute form. The fungus gradually invades tissue over several months, making symptoms less dramatic. Patients may experience persistent, low-grade fever and chronic pain or pressure within the face, often mimicking a refractory chronic bacterial sinus infection.
This slow progression allows for subtle, long-term tissue destruction, eventually manifesting as gradually worsening eye problems. Symptoms like decreased visual acuity or reduced eye mobility may develop slowly as the fungus erodes the bone. These issues, collectively known as orbital apex syndrome, involve the superior structures of the orbit.