Distinguishing between sinusitis and other nasal conditions such as allergic rhinitis and the common cold can be difficult since the symptoms are often similar (Balkissoon 2010). Viral sinusitis is the most common form of sinus infection, and typically produces symptoms similar to those of the common cold that last approximately 10 days (Smith 2012; Leung 2008; Balkissoon 2010). However, symptoms of acute bacterial sinusitis typically last 10-30 days and are more severe than those of the common cold or viral sinusitis (NIAID 2012; Balkissoon 2010; Leung 2008).
Throbbing facial pain or pressure is a prominent feature in many cases of sinusitis. This symptom typically originates in the same location as the affected sinus (eg, in the forehead, cheeks, nose, or between the eyes). The pain associated with sinusitis is a result of increased pressure caused by trapped air and mucus, which pushes on the sinus mucous membrane and bony wall behind it. Sinus pain can also be caused by negative pressure within the sinuses, which occurs due to blocked sinus openings that do not allow air to enter, thus creating a vacuum space (NIAID 2012).
Sinusitis is also often marked by a change in the characteristics of nasal secretions, which progress from clear and watery to thick and opaque (eg, white, yellowish, greenish, or blood-tinged) (DeMuri 2009; NIAID 2012). The mucus becomes thick because it loses its water content while trapped in the sinus cavity. It also becomes saturated with inflammatory mediators (NIAID 2012) and appears discolored as it mixes with neutrophils, a type of white blood cell (Rosenfeld 2007).
Other symptoms linked to sinusitis include (AAFP 2008, 2011; NIH 2012; Mayo Clinic 2012b):
- Postnasal drip
- Sore throat
- Reduced sense of smell and taste
- Halitosis (ie, bad breath)
- Ear pain/pressure
- Nasal congestion and runny nose
- Cough (may be worse at night)
- Aching teeth
When symptoms of the common cold or viral sinusitis do not improve after 10 days or worsen after 5 days, bacterial sinusitis may be suspected (Balkissoon 2010; DeMuri 2009).
Sinusitis can be classified as follows (Radojicic 2010):
- Acute – Symptoms last less than 4 weeks
- Subacute – Symptoms last from 4 to 8 weeks
- Chronic – Symptoms last longer than 8 weeks
- Recurrent acute – Symptoms occur 3 or more times per year and last less than 2 weeks