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Overview

What Is Sinusitis?

Sinusitis is inflammation or swelling of the lining of the sinuses, the air-filled spaces around the nose, cheeks, eyes, and forehead. Swelling can block the small openings that normally let mucus drain into the nose, causing mucus and pressure to build up. Sinusitis often follows a cold or another respiratory infection, but allergies and other problems can also contribute. It may be temporary and improve within weeks, or it can become chronic and last for months or recur frequently.

Symptoms

Sinusitis Symptoms

Sinusitis symptoms can vary depending on the cause and how long the inflammation lasts. Common symptoms include nasal blockage, facial discomfort, and changes in mucus, although not everyone has the same combination.

  • Facial pressure or pain may occur around the cheeks, eyes, nose, or forehead.
  • Nasal congestion can make it difficult to breathe through the nose.
  • Thick nasal drainage may be clear, white, yellow, or green.
  • A reduced sense of smell (hyposmia) may occur.
  • A cough can develop when mucus drains down the throat.
  • Headache may occur with pressure or congestion.
  • Fever can occur, particularly with some infections.

Important distinction

Symptoms can overlap

A cold can cause congestion and drainage, while allergies often cause itching, sneezing, and watery discharge. COVID-19 can also cause congestion, cough, fever, or loss of smell, so symptoms alone cannot confirm sinusitis or distinguish it from another illness. Testing or a medical assessment may be appropriate when symptoms are severe, persistent, or unusual.

Causes

What Causes Sinusitis?

Sinusitis develops when inflammation and swelling interfere with normal mucus drainage from the sinuses. This commonly happens after a viral upper-respiratory infection, such as a cold, but allergies, irritants, and structural blockage can have a similar effect. Trapped mucus can create an environment where inflammation continues and, in selected cases, bacteria grow.

  • Viral infections, including common colds, are the most frequent triggers.
  • Bacterial infection can develop in some cases, especially when symptoms are severe, persistent, or worsen after initial improvement.
  • Allergies can inflame the nasal and sinus lining and interfere with drainage.
  • Nasal polyps can block sinus openings and contribute to ongoing inflammation.
  • A deviated septum or other structural blockage can make drainage difficult.
  • Smoke, air pollution, and other irritants can inflame the nose and sinuses.

Risk Factors

Risk Factors for Sinusitis

Risk-factor typeExamples
Modifiable or exposure-relatedSmoking or secondhand smoke, air pollution, workplace irritants, and poorly controlled allergies
Medical or inflammatoryAsthma, allergies, immune-system problems, recurrent respiratory infections, and chronic nasal inflammation
Anatomical or non-modifiableNasal polyps, a deviated septum, narrow sinus openings, or other structural drainage problems
Pattern-relatedPrevious episodes of sinusitis or symptoms that repeatedly return

Allergies and asthma can keep the nasal passages inflamed, while nasal polyps or a deviated septum may physically limit drainage. Smoking, secondhand smoke, and other irritants can worsen swelling, and frequent respiratory infections provide more opportunities for sinus inflammation. People with recurring symptoms may be at greater risk of chronic sinusitis and should discuss possible underlying causes with a clinician.

Complications

Sinusitis Complications

Most sinusitis improves without serious complications. However, prolonged or severe infection can rarely spread from the sinuses to nearby tissues, particularly around the eyes or, more rarely, the brain and its coverings. Persistent or worsening symptoms deserve medical assessment.

  • Repeated sinus infections can interfere with daily life and may require evaluation for an underlying cause.
  • Ongoing inflammation can contribute to chronic sinusitis.
  • An infection may spread to tissues around the eye (orbital infection).
  • A severe infection can rarely affect nearby facial bones (osteomyelitis).
  • In very rare cases, infection can involve tissues around the brain or cause other intracranial complications.

Seek prompt care

Rare complications need urgent attention

Seek prompt medical care for vision changes, swelling around an eye, severe headache, confusion, a stiff neck, or marked facial swelling. These symptoms may indicate that an infection is spreading beyond the sinuses.

Diagnosis

How Sinusitis Is Diagnosed

Clinicians diagnose sinusitis mainly from the symptom pattern, how long symptoms have lasted, and a physical examination. They may ask about recent colds, allergies, repeated episodes, fever, and symptoms that could point to another condition. Examination can include looking inside the nose for swelling or drainage and checking for facial tenderness. Routine imaging is usually not needed for uncomplicated symptoms.

  • Nasal endoscopy may be used when symptoms persist, recur, or need a closer view of the nasal passages and sinus openings.
  • An allergy assessment may help identify triggers when symptoms suggest allergic inflammation.
  • A mucus or sinus culture may be considered for severe, persistent, recurrent, or treatment-resistant infections.
  • CT imaging may be used for chronic or complicated disease, suspected structural blockage, or planning specialist treatment.
  • Other testing may be considered when the symptoms suggest a cold, migraine, dental problem, COVID-19, or another condition.

Treatment & Management

Sinusitis Treatment and Management

First-line symptom relief

  • Use saline nasal irrigation with sterile, distilled, or previously boiled and cooled water and clean equipment.
  • Drink fluids to help maintain hydration and support normal mucus clearance.
  • Use humidified air or breathe in steam carefully to reduce dryness and irritation.
  • Rest as needed while your body recovers from the infection or inflammation.
  • Use an appropriate pain or fever medicine according to the label and your clinician’s advice.

When further treatment is needed

Antibiotics do not help most viral cases and should be used only when a clinician believes a bacterial infection is likely or confirms another reason for them. Depending on the cause, sinusitis treatment may include nasal corticosteroids, allergy treatment, or other clinician-directed medicines. Persistent or chronic sinusitis may require evaluation by an ear, nose, and throat specialist, especially when nasal polyps or structural blockage are present. In selected cases, surgery may improve drainage when medicines and other measures have not controlled the problem.

Prevention

Can Sinusitis Be Prevented?

  • Wash your hands regularly and avoid close contact with people who have respiratory infections when possible.
  • Avoid tobacco smoke and limit exposure to dust, fumes, and other nasal irritants.
  • Manage allergies according to a clinician’s treatment plan.
  • Use safe water and clean equipment for any nasal-rinse practice.
  • Follow prescribed treatment plans when sinusitis or nasal inflammation keeps recurring.
  • Ask about recommended vaccines and other measures that reduce respiratory infection risk.

Prevention focuses on reducing triggers and recurrence because some sinusitis episodes follow respiratory infections that cannot be completely avoided. Managing allergies, avoiding smoke, and treating ongoing nasal inflammation may lower the chance of repeated symptoms, but no approach prevents every episode.

Outlook and Prognosis

Outlook for Sinusitis

Acute sinusitis often improves over days to weeks as a viral infection or temporary inflammation settles. Chronic sinusitis can take longer to control and may require treatment for allergies, nasal polyps, asthma, structural blockage, or another contributing condition. Symptoms that keep returning or do not improve should be reassessed rather than treated repeatedly without identifying the cause.

When Should You See a Doctor

When Should You See a Doctor for Sinusitis?

  • Arrange medical care when symptoms last longer than expected, worsen, or return repeatedly.
  • Seek advice for severe facial pain, a high or persistent fever, or symptoms that interfere substantially with daily activities.
  • Have a young child assessed when symptoms are concerning, severe, or difficult to manage at home.
  • Talk with a clinician if you have an immune-system condition or another concern that could increase the risk of complications.
  • Ask for evaluation when symptoms do not improve with recommended sinusitis treatment or keep coming back.

Urgent symptoms

Get immediate medical help

Get immediate medical help for swelling around the eye, vision changes, severe headache, confusion, stiff neck, marked facial swelling, or rapidly worsening illness. These signs may indicate a serious infection that needs urgent treatment.

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