Sinusitis is an inflammation of the nasal passages and can be acute or chronic. This summary focuses on acute sinusitis, although the signs and symptoms are similar between the 2 conditions.
Acute sinusitis, or more accurately acute rhinosinusitis, is an inflammation of the mucosal lining of the nasal passage and paranasal sinuses lasting up to 4 weeks. Per the 2012 National Health Interview Survey, about 12% of non-institutionalized adults are diagnosed with acute sinusitis each year. Incidence rates are higher for women and adults between the ages of 45 and 74. Factors that increase the risk for acute sinusitis include age (older individuals and young children are more frequently affected), smoke and other air pollutants, asthma, allergies, dental disease, swimming, and air travel and other changes in atmospheric pressure. Other contributing factors include smoking and infections. Moreover, acquired or congenital immunosuppression, cystic fibrosis, gastroesophageal reflux disease, AIDS, and poorly controlled diabetes can increase the risk for acute invasive fungal sinusitis.
The challenge in diagnosing acute bacterial rhinosinusitis (ABRS) is differentiating this entity from viral upper respiratory tract infection (URI). While most viral URIs have a better-defined presentation (fever and constitutional symptoms for 24-48 hours, peak or respiratory symptoms by days 3-6, and then improvement), rhinosinusitis due to bacterial causes may differ in initial presentation and course; high fever and purulent nasal discharge occur for at least 3-4 consecutive days at the start of illness.
The Infectious Diseases Society of America recommends that clinicians look for 3 typical clinical presentations to aid in the diagnosis of acute bacterial rhinosinusitis.
Persistent symptoms for >10 days without improvement.
Severe symptoms (high fever ≥39°C [102°F]; purulent nasal discharge) for ≥3-4 consecutive days at the start of illness.
Worsening symptoms, characterized by typical viral URI symptoms that appear to be improving followed by sudden onset of worsening symptoms after 5-6 days ("double-sickening").
Although considered the classic presentation in adults, the complete triad of headache, facial pain, and fever is uncommon. Primary symptoms include these as well as nasal obstruction, nasal discharge, anosmia, cough, dental pain, fatigue, and malodorous breath.
In children the most common signs are cough, nasal discharge, fever, and bad breath.
It can be challenging to differentiate acute bacterial sinusitis from viral sinusitis, especially in the first few days. Most viral URIs are characterized by fever and constitutional symptoms for 24-48 hours, with peak or respiratory symptoms by days 3-6, and then improvement.
Chronic sinusitis is usually defined by duration >12 weeks.
Rhinitis, whether allergic or non-allergic (medication induced, occupational, vasomotor, etc), can be differentiated from acute bacterial sinusitis by presentation and duration of symptoms, seasonal variation, and temporal relationships to known irritants; may require further evaluation by an ear-nose-throat (ENT) or allergy specialist.