Acute sinusitis, also known as acute rhinosinusitis, is a common condition that affects millions of people worldwide. It occurs when the cavities around the nasal passages (sinuses) become inflamed and swollen, leading to a build-up of mucus and difficulty in breathing through the nose. While often short-lived, acute sinusitis can cause significant discomfort and impact daily life. Understanding its symptoms and causes is essential for prompt diagnosis and effective treatment.
What is Acute Sinusitis?
Acute sinusitis is the inflammation of the paranasal sinuses, typically resulting from a viral infection associated with the common cold. The term “acute” refers to a condition that appears suddenly and lasts for a short duration—usually less than four weeks. It differs from chronic sinusitis, which lasts for more than 12 weeks and may involve persistent inflammation.
Types of Sinuses Involved
Humans have four pairs of sinuses:
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Maxillary sinuses (cheekbones)
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Frontal sinuses (forehead)
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Ethmoid sinuses (between the eyes)
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Sphenoid sinuses (behind the eyes)
Acute sinusitis can affect one or more of these sinus cavities.
Symptoms of Acute Sinusitis
The symptoms of acute sinusitis can range from mild to severe and may mimic those of a common cold or allergy, but they typically persist longer and may worsen over time.
Most Common Symptoms:
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Facial pain or pressure
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Pain may be localized to the cheeks, forehead, or between the eyes.
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Pain worsens when bending over or lying down.
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Nasal congestion
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Blocked nasal passages due to inflamed tissues.
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Difficulty breathing through the nose.
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Nasal discharge
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Thick, yellow or green mucus from the nose or draining down the back of the throat (postnasal drip).
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Headache
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Often described as a deep, throbbing pain in the affected sinus area.
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Reduced sense of smell and taste
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Cough
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Often worse at night due to postnasal drip irritating the throat.
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Fever
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May occur if the sinusitis is caused by a bacterial infection.
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Tooth pain or ear pressure
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Especially common when maxillary sinuses are involved.
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Fatigue
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General sense of tiredness and discomfort.
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Bad breath (halitosis)
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Caused by stagnant mucus in the sinuses.
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Duration of Symptoms
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Acute sinusitis typically lasts less than 4 weeks.
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If symptoms persist beyond 10 days without improvement, it may indicate a bacterial infection rather than a viral one.
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If the symptoms recur frequently (e.g., more than four times a year), the condition may be diagnosed as recurrent acute sinusitis.
Causes of Acute Sinusitis
Acute sinusitis can be caused by several factors, including infections, allergies, and structural issues in the nasal passages.
1. Viral Infections (Most Common Cause)
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Up to 90% of acute sinusitis cases are caused by viruses.
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Often follows a cold or upper respiratory tract infection.
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Viral sinusitis typically improves on its own within 7 to 10 days.
2. Bacterial Infections
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Responsible for about 5–10% of cases.
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Bacteria invade the sinuses after a viral infection compromises the sinus lining.
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Common bacterial culprits include:
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Streptococcus pneumoniae
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Haemophilus influenzae
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Moraxella catarrhalis
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3. Fungal Infections
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Rare in healthy individuals.
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More common in people with compromised immune systems.
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Can lead to severe forms such as invasive fungal sinusitis.
4. Allergies
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Allergic rhinitis (hay fever) can cause inflammation and blockage of the sinus passages.
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Chronic exposure to allergens such as dust mites, pollen, or pet dander may trigger sinusitis.
5. Nasal Polyps
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Noncancerous growths in the nasal passages can obstruct the sinuses and lead to infections.
6. Deviated Nasal Septum
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A crooked or displaced septum can restrict airflow and block sinus drainage.
7. Respiratory Tract Conditions
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Conditions such as asthma or cystic fibrosis may increase the risk of sinus inflammation.
8. Environmental Factors
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Exposure to smoke, pollution, chemical irritants, or changes in air pressure (such as during flying or diving) can also trigger sinus inflammation.
9. Dental Infections
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Infections in the upper teeth can spread to the maxillary sinuses due to their proximity.
Risk Factors
Certain individuals are more prone to developing acute sinusitis, including:
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People with frequent colds or respiratory infections.
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Individuals with allergies or asthma.
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Smokers and those exposed to secondhand smoke.
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People with weakened immune systems.
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Children attending daycare or school.
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People with structural abnormalities in the nasal cavity.
Complications (Rare but Serious)
While acute sinusitis usually resolves without complications, in rare cases it can lead to:
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Chronic sinusitis – when inflammation lasts more than 12 weeks.
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Orbital cellulitis – an infection of the eye socket.
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Meningitis – if the infection spreads to the brain or spinal cord.
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Osteomyelitis – infection of the surrounding bones.
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Vision problems – due to pressure or infection affecting the optic nerve.
When to See a Doctor
Seek medical attention if:
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Symptoms persist longer than 10 days without improvement.
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You have a high fever (above 102°F or 39°C).
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Severe facial pain or swelling occurs.
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Vision changes or confusion develop.
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You have repeated episodes of acute sinusitis.
Diagnosis
Doctors typically diagnose acute sinusitis based on a physical exam and medical history. Additional tests may include:
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Nasal endoscopy – using a thin tube with a camera to view inside the sinuses.
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CT scan – to assess sinus anatomy and detect blockages or complications.
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Allergy testing – if allergic triggers are suspected.
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Culture tests – to identify bacterial or fungal infections.
Summary
Acute sinusitis is a common and typically short-term inflammation of the sinuses, often caused by viral infections but sometimes triggered by bacteria, allergies, or structural issues. Recognizing the symptoms—such as facial pain, nasal congestion, and thick mucus—can help in timely treatment and prevent complications. Most cases resolve on their own or with minimal intervention, but persistent or severe cases may require medical evaluation and targeted therapy.