Are there different types of sinusitis?

Classification by Location

There are several pairs of sinuses, including the frontal, ethmoid, maxillary and sphenoid sinuses.
The ethmoid sinuses can also be further broken down into anterior and posterior.
Sinusitis can be classified by the sinus cavity which it affects:

Maxillary sinusitis - can cause pain or pressure in the maxillary (cheek) area (e.g., toothache, headache)
Frontal sinusitis - can cause pain or pressure in the frontal sinus cavity (located behind/above eyes), headache
Ethmoid sinusitis - can cause pain or pressure pain between and/or behind eyes, headache
Sphenoid sinusitis - can cause pain or pressure behind the eyes, but often refers to the vertex of the head

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. All forms of sinusitis may either result in, or be a part of, a generalized inflammation of the airway so other airway symptoms such as cough may be associated with it.

By duration

Sinusitis can be acute (going on less than four weeks), subacute (4-12 weeks) or chronic (going on for 12 weeks or more).

All three types of sinusitis have similar symptoms, and are thus often difficult to distinguish.

Acute sinusitis

Acute sinusitis is usually precipitated by an earlier upper respiratory tract infection, generally of viral origin. Virally damaged surface tissues are then colonized by bacteria, most commonly Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Staphylococcus aureus. Other bacterial pathogens include other streptococci species, anaerobic bacteria and, less commonly, gram negative bacteria.

Another possible cause of sinusitis can be dental problems that affect the maxillary sinus.

Acute episodes of sinusitis can also result from fungal invasion. These infections are most often seen in patients with diabetes or other immune deficiencies (such as AIDS or transplant patients on anti-rejection medications) and can be life threatening. In type I diabetes, ketoacidosis causes sinusitis by Mucormycosis.

Chronic sinusitis

Chronic sinusitis is a complicated spectrum of diseases that share chronic inflammation of the sinuses in common. The causes are multifactorial and may include allergy, environmental factors such as dust or pollution, bacterial infection, and/or fungus (either allergic, infective or reactive). Non allergic factors such as Vasomotor rhinitis can also cause chronic sinus problems.

Symptoms include: Nasal congestion; facial pain; headache; fever; general malaise; thick green or yellow discharge; feeling of facial 'fullness' worsening on bending over; aching teeth.
Very rarely, chronic sinusitis can lead to Anosmia, the inability to smell or detect odors.

In a small number of cases, chronic maxillary sinusitis can also be brought on by the spreading of bacteria from a dental infection.

Fungus

A more recent, and still debated, development in chronic sinusitis is the role that fungus may play. Fungus can be found in the nasal cavities and sinuses of most patients with sinusitis, but can also be found in healthy people as well. It remains unclear if fungus is a definite factor in the development of chronic sinusitis and if it is, what the difference may be between those who develop the disease and those who do not.