Acute Sinusitis (Sinus Infection)

What happens in acute sinusitis

The sinuses are four pairs of air-filled spaces in the face bones: the maxillary (cheeks), frontal (forehead), ethmoid (between the eyes) and sphenoid (deep behind the nose). They are lined with mucus-producing tissue and drain through narrow openings into the nose.

When a cold or allergy makes this lining swell, the openings block. Mucus builds up, pressure rises and the trapped mucus can become infected. Doctors often say rhinosinusitis, because the nose lining is always involved too.

How sinusitis is classified by duration

Symptoms

The AAO-HNS guideline defines acute sinusitis as up to 4 weeks of cloudy or colored nasal discharge plus nasal blockage, facial pain, pressure or fullness, or both. Other common symptoms:

• reduced or lost sense of smell
• post-nasal drip and cough, often worse at night
• frontal headache or pain around the eyes
• pain in the upper teeth
• ear fullness
• tiredness and mild fever
• bad breath

Facial pain typically worsens when bending forward.

Coryza vs sinus infection

Coryza, the runny nose of a common cold, and sinusitis overlap, because nearly every cold inflames the sinuses to some extent.

Viral vs bacterial sinusitis

Mucus color does not tell viral from bacterial infection. Doctors use the pattern of illness. Acute bacterial sinusitis is likely when:

1. Persistent: symptoms last 10 days or more without improving.
2. Severe: high fever of 39 °C (102.2 °F) or above with pus-like discharge or facial pain for 3 to 4 days in a row at the start.
3. Double sickening: symptoms improve, then worsen again with new fever, headache or discharge.

The main bacteria are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis.

Causes and risk factors

• Viral colds, by far the most common trigger
• Allergic rhinitis, which keeps the lining swollen
• Structural blockage: a deviated septum, nasal polyps or enlarged adenoids in children
• Dental infection of the upper back teeth, which can spread into the maxillary sinus, often with a foul smell
• Smoking and secondhand smoke
• Swimming and diving, and air travel with congestion
• Weakened immunity, cystic fibrosis and diabetes

Diagnosis

Acute sinusitis is diagnosed from your symptoms and a brief examination of the nose, throat, ears and face. Tests are not routinely needed. CT scans are not recommended for uncomplicated acute sinusitis, because they show sinus changes in almost every cold. Imaging is reserved for suspected complications, such as spread to the eye or brain, or for chronic or recurrent cases. Nasal endoscopy by an ENT specialist can be used for persistent or recurrent symptoms.

Treatment

Symptom relief (all cases)

• Saline nasal irrigation: rinsing with a squeeze bottle or neti pot clears mucus. Use distilled, sterile, or boiled and cooled water, never plain tap water.
• Steroid nasal sprays (fluticasone, mometasone, budesonide): reduce swelling and may shorten symptoms.
• Pain relievers: acetaminophen (paracetamol) or ibuprofen at the label dose.
• Decongestant nasal sprays for no more than 3 days, to avoid rebound congestion. Oral decongestants are not suitable for people with high blood pressure, heart disease or glaucoma.
• Warm compresses, steam, rest and fluids.
• Antihistamines help only if allergies are contributing.

Antibiotics

Most people with acute sinusitis do not need antibiotics. For likely bacterial sinusitis in adults, guidelines allow either watchful waiting with a safety-net prescription for 7 days, or starting antibiotics. When used, amoxicillin or amoxicillin-clavulanate is first-line, typically for 5 to 7 days in adults and 10 days in children. Alternatives exist for penicillin allergy.

When to see an ENT specialist

Referral is considered for recurrent or chronic sinusitis, complications, suspected polyps or tumors, or symptoms on one side only. Endoscopic sinus surgery is an option for chronic or recurrent disease that does not respond to medical treatment.

Complications

Complications are rare but serious:

• Orbital cellulitis and abscess: eye swelling, pain, bulging and vision changes, more common in children
• Meningitis and brain abscess
• Frontal bone infection with forehead swelling (Pott's puffy tumor)
• Cavernous sinus thrombosis, a clot in a vein behind the eyes

Prevention

• wash hands and get yearly flu vaccines
• treat allergies with steroid sprays and antihistamines
• avoid smoke
• use saline rinses during colds if you are prone to sinusitis
• keep indoor air comfortably humid

Frequently asked questions

How long does a sinus infection last?

Most viral acute sinusitis improves within 7 to 10 days and clears within 2 to 3 weeks. Bacterial sinusitis usually improves within a few days of antibiotics. Symptoms lasting longer than 4 weeks are subacute, and beyond 12 weeks are chronic sinusitis.

How can I tell if my sinus infection is bacterial or viral?

Doctors use timing rather than mucus color. Bacterial infection is likely if symptoms last 10 days or more without improving, begin with high fever and severe symptoms for 3 to 4 days, or get better and then worse again. Otherwise, the infection is usually viral.

What is the difference between coryza and a sinus infection?

Coryza is the runny, sneezy nose of a common cold and usually settles within a week. A sinus infection causes more blockage, thick discharge, facial pain or pressure and reduced smell, and often lasts longer. Most colds involve some sinus inflammation, which usually clears on its own.

Do I need antibiotics for sinusitis?

Usually not. Most acute sinusitis is viral, and antibiotics do not help viruses. Even for likely bacterial sinusitis, many adults recover without them. Antibiotics are considered for persistent, severe or worsening symptoms, or for people with a weakened immune system.

What is the fastest way to relieve sinus pressure?

Saline nasal rinses, a steroid nasal spray, warm compresses on the face, steam, and acetaminophen or ibuprofen give the quickest relief. A decongestant spray can help for up to 3 days. Rest and fluids support recovery.