The presence of eosinophils in the mucous lining of the nose and paranasal sinuses has been demonstrated for many people, and this has been termed eosinophilic mucin rhinosinusitis (EMRS). Cases of EMRS may be related to an allergic response, but allergy is not often documented, resulting in further subcategorization into allergic and nonallergic EMRS.A more recent, and still debated, development in chronic sinusitis is the role that fungi play in this disease. Whether fungi are a definite factor in the development of chronic sinusitis remains unclear, and if they are, what is the difference between those who develop the disease and those who remain free of symptoms. Trials of antifungal treatments have had mixed results.Recent theories of sinusitis indicate that it often occurs as part of a spectrum of diseases that affect the respiratory tract (i.e., the "one airway" theory) and is often linked to asthma.Both smoking and secondhand smoke are associated with chronic rhinosinusitis.Other diseases such as cystic fibrosis and granulomatosis with polyangiitis can also cause chronic sinusitis. Pathophysiology
Biofilm bacterial infections may account for many cases of antibiotic-refractory chronic sinusitis. Biofilms are complex aggregates of extracellular matrix and interdependent microorganisms from multiple species, many of which may be difficult or impossible to isolate using standard clinical laboratory techniques. Bacteria found in biofilms have their antibiotic resistance increased up to 1000 times when compared to free-living bacteria of the same species. A recent study found that biofilms were present on the mucosa of 75% of people undergoing surgery for chronic sinusitis.
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include:

Business and management
Business process, activities that produce a specific service or product for customers
Business process modeling, activity of representing processes of an enterprise in order to deliver improvements
Manufacturing process management, a collection of technologies and methods used to define how products are to be manufactured.