How does allergic fungal sinusitis (AFRS) cause bone destruction?

Allergic fungal sinusitis (AFRS) is characterized by a hypersensitivity reaction to the presence of fungi in the sinuses. The correct choice highlights that the disease process involves the growth of expansile fungal hyphae along with the production of allergic mucin. This combination leads to a significant inflammatory response within the sinus cavities.

The fungal hyphae can infiltrate and expand within the sinus tissue, and the associated allergic mucin can contribute to the formation of a thick, gelatinous mass that can obstruct normal sinus drainage and airflow. As these masses grow, they can cause direct pressure on adjacent structures, including the bone. This pressure, combined with the inflammatory response elicited by the fungal elements and the associated mucin, can lead to bone remodeling and destruction over time.

Understanding this mechanism is essential for recognizing how AFRS differs from other types of sinusitis, as it emphasizes the role of a non-invasive fungal infection in its pathophysiology, rather than a direct invasion of pathogens or secondary complications arising from reduced blood flow. Therefore, recognizing the dynamic interplay between fungal growth and inflammatory processes is crucial in understanding the disease's progression and the resultant bone changes.