Fungal sinusitis, also known as mycosis fungoides, is a disease in which a fungal infection occurs inside the sinuses, leading to the corresponding clinical manifestations. Generally speaking, the sinus mucosa has a self-purifying function, and the fungus is not easily colonized and developed. In recent years, the incidence of fungal sinusitis has been on the rise, and infected patients may be found during routine physical examinations, which may be related to the widespread use of antibiotics and environmental pollution.
The common causative agent of fungal sinusitis is mainly Aspergillus, accounting for more than 80%, and others are Candida, Trichophyton, and Schenicola. The above pathogenic fungi can be infected alone or in combination. Clinically, fungal sinusitis is divided into invasive fungal sinusitis and non-invasive fungal sinusitis. Invasive fungal sinusitis is characterized by fungal infection not only in the sinus cavity, but also in the mucosa and bone wall of the sinuses, as well as expansion into the peripheral structures and tissues outside the sinuses. Clinical manifestations include fever, massive purulent crusting, periorbital and cheek swelling, pain, protruding eyeballs, conjunctival congestion, ocular muscle paralysis, loss of vision, and retro-orbital pain. The disease is critical, progresses rapidly, and has a very high mortality rate; fortunately, the incidence is very low. Non-invasive fungal sinusitis is the most common form of the disease, which is slow to develop, with the infection limited to the sinus mucosa and can be cured with regular treatment. The following highlights the manifestations and treatment of this disease.
Non-invasive fungal sinusitis mostly starts unilaterally in the sinuses, with the highest incidence in the maxillary sinus, followed by the pterygoid sinus, septal sinus, and rarely in the frontal sinus. According to the type of pathology, there are two types of fungal sinusitis: fungal ball and allergic fungal rhinosinusitis. The former is more common in the elderly, and more women than men. Patients are usually immunocompetent. The clinical manifestations resemble chronic sinusitis, such as unilateral nasal congestion, runny nose, or foul odor. It may also not show any symptoms. Sinus CT shows uneven density increase in the sinus cavity and high density calcified spots or dots without bone destruction, some clinicians call this specific manifestation the “dirt” sign, which is very graphic. Allergic fungal rhinosinusitis occurs mostly in adults and young people with atopic constitution, often accompanied by nasal polyps and bronchial asthma. The disease has an insidious onset, progresses slowly, and involves more than one group of sinuses on one side. The clinical manifestations are related to the duration and extent of the lesion, with dilated sinus enlargement and compressive resorption of the sinus wall as the lesion develops in the sinuses. The clinical manifestation is a slowly progressive periorbital or maxillofacial bulge that is painless, fixed, hard and irregular in shape. CT of the sinuses shows a central hairy glassy or linear lesion with a stellate distribution of calcified dots, which is actually a high-density allergic mucin shadow.
When the history, signs and sinus CT examination are similar to the above manifestations, fungal sinusitis needs to be highly suspected and needs to be treated promptly at the ENT department. Non-invasive fungal sinusitis is usually treated by nasal endoscopic surgery to completely remove the lesion and the lesioned tissue, preserve the normal mucosa, and improve the ventilation and drainage of the sinuses. Postoperative treatment of sinusitis can be done in the perioperative period without oral or sedative antifungal drugs. Once the diagnosis of invasive fungal sinusitis is confirmed, surgery should be performed as soon as possible to remove fungal pathogens and necrotic and irreversible lesions in the nasal cavity and sinuses, and to apply strong antifungal medications.