For most people, sinusitis is just a temporary infection that clears up on its own. But sometimes, if left untreated, it can spread and lead to complications that are painful and even dangerous. Read on to discover the most common complications of untreated sinusitis and the importance of taking timely and proper care.

What is sinusitis?

Sinuses are the air-filled spaces found behind your forehead, nose, cheeks, and eyes. When these spaces get inflamed or irritated, it can lead to sinusitis or sinus infection. Sinusitis could be due to bacterial infections, viral infections, or allergies, leading to blockages and fluid buildup. When sinus tissues become inflamed or swollen, they block the normal flow of mucus, which usually helps trap dust, germs, and other particles, and moves them out of the sinuses. This blockage can cause mucus to build up, creating an environment where bacteria can grow.

This can cause some symptoms, such as:

• A blocked or stuffy nose
• Greenish nasal discharge
• Postnasal drip (mucus draining down the throat)
• Facial tenderness, especially around the upper part of the nose and under the eyes.
• Toothaches
• Headaches behind the forehead
• Coughing
• Fever
• Fatigue
• Bad breath (halitosis)

Why is it dangerous to leave sinusitis untreated?

Leaving sinusitis untreated can be dangerous because the sinuses are located close to the brain and eyes, which can increase the risk of severe complications. 

Otolaryngologist (a healthcare specialist who treats conditions affecting the ears, nose and throat) Raj Sindwani, explains that sinusitis usually clears up on its own, but if it persists, it's important to consult a doctor. If the infection is bacterial, antibiotics may be considered. 

Sinusitis affects many people and can be classified into different types depending on how long the symptoms last:¹

• Acute sinusitis lasts up to 4 weeks
• Subacute sinusitis spans 4 to 12 weeks
• Chronic sinusitis persists for over 12 weeks, sometimes continuing for months or years
• Recurrent sinusitis involves multiple episodes in a year

Chronic sinusitis can be caused due to underlying conditions like asthma, allergies, or a deviated septum, which require treating the root cause rather than using antibiotics. While not all acute sinus infections lead to chronic issues, keeping an eye on your symptoms and how long they last can help prevent complications and lead to quicker recovery.

Possible complications of untreated sinusitis

Complications from sinus infections are rare, occuring in about 1 in every 1,000 cases.²

Eye complications

Most complications affect the eye socket because it's separated from the sinuses by a thin bone. These complications can include:³

• Preseptal cellulitis: Swelling around the eyelids, often with redness and warmth
• Orbital cellulitis: Infection in the muscles and fat around the eye, causing redness, swelling, bulging, and potential vision loss
• Subperiosteal abscess: Pus buildup in the eye socket, leading to swelling, redness, and reduced eye movement

Bone complications

An infection in the frontal sinuses can lead to a serious and potentially life-threatening condition called osteomyelitis. This is a severe infection that causes inflammation in the bones.⁴

Brain complications 

Some sinus cavities are close to the brain and could spread to the brain if left untreated. Although this is rare, it can be serious and even life-threatening, so it’s important to address it quickly. Some of the complications that can happen to the brain from most common to least common include:⁵ 

• Subdural empyema: a collection of pus that forms between the outer layer (dura mater) and the middle layer (arachnoid mater) of the tissues surrounding the brain
• Intracerebral abscess: Buildup of pus caused by an infection in the brain and subsequent swelling could put pressure on the brain
• Extradural abscess: An extradural abscess is a buildup of pus that forms between the skull and the outermost layer of tissue covering the brain (dura mater)
• Meningitis: An inflammation of the brain’s protective membranes
• Cavernous sinus thrombosis: A blood clot in spaces behind the eyes, causing swelling, bulging, severe eye pain, vision problems, and difficulty moving the eyes
• Superior sagittal sinus thrombosis: Blood clot forms in a major vein in the brain called the superior sagittal sinus. This can block blood flow and lead to swelling and pressure in the brain⁶ 

Respiratory complications

Chronic sinusitis can cause or worsen respiratory problems, such as asthma, chronic obstructive pulmonary disease (COPD), and bronchiectasis. Research indicates that nearly all asthma patients also suffer from rhinitis (inflammation of the nasal passages), and those with rhinitis are three times more likely to develop asthma.

Many people with COPD and bronchiectasis also experience sinus issues. Treating chronic sinusitis can help improve asthma symptoms, especially in cases where standard treatments are ineffective. This suggests that problems in the upper and lower airways are often linked and might be related to the same underlying condition.⁷

When is it time to get treatment? 

If you get sinusitis, you should keep track of your sinus infection’s duration and progression. If it doesn’t improve within seven to ten days, consult a healthcare provider. The Centers for Disease Control and Prevention (CDC) also recommends seeing a doctor if:

• You have severe facial pain or headache
• Your symptoms persist for more than ten days without improvement
• Your symptoms worsen after initially improving
• You have a fever lasting more than 3–4 days
• You have had multiple sinus infections in the past year

A healthcare provider can diagnose sinusitis by reviewing your symptoms, medical history, and examining your ears, nose, and throat for signs of swelling, drainage, or blockage. They may use different tools and tests, such as:

• Nasal endoscopy: Using a small camera to look inside your nose
• Nasal swabs: Collecting a fluid sample from your nose to check for viruses or bacteria
• Imaging: A computed tomography scan may be used to get a clearer view of your sinuses
• Allergy testing: If sinusitis is chronic, allergy tests may be done to identify possible triggers
• Biopsy: In rare cases, a tissue sample from your nose might be taken for further testing

How is sinusitis treated?

A healthcare provider may suggest several treatment options based on the type and severity of sinusitis. 

Antibiotics 

Antibiotics are commonly used to treat bacterial sinus infections. The duration of treatment typically ranges from 3 to 28 days, depending on the specific antibiotic. Since the sinuses are deep within the bones and have limited blood supply, people with more severe or persistent sinusitis may require longer courses of antibiotics.

Antibiotics work by eliminating the bacteria causing the infection, but they do not provide immediate relief from symptoms. Over-the-counter medications can be used to alleviate discomfort. Additionally, patients should consider antibiotics if symptoms persist beyond 7–10 days, as overuse can lead to antibiotic resistance.

Nasal decongestant sprays 

These sprays can reduce nasal swelling and improve drainage, but should only be used for three to four days. Patients shouldn’t overuse these sprays to avoid "rebound congestion’’, a condition where nasal passages swell.

Antihistamines

Antihistamines can prevent inflammation caused by allergies, which can help manage the symptoms that cause swollen nasal and sinus passages.

Using a combination of drugs 

Over-the-counter decongestants and antihistamine combinations should be used when prescribed by an allergist. This is because some drugs contain ingredients which can thicken mucus.

Topical nasal corticosteroids 

Prescription nasal sprays can reduce inflammation in the nasal passages and sinuses. They can also prevent the recurrence of nasal polyps, and provide long-term relief without the risk of dependency.

Nasal saline washes

Saline rinses can help clear the nasal passages

Surgery

If medications do not work, surgery may be recommended. An otolaryngologist usually performs these procedures to correct anatomical defects, remove nasal polyps, or clear blocked passages. The surgery can be done using local or general anaesthesia, and patients typically return home the same day.

Summary

Sinusitis is a common condition where the sinuses become inflamed, usually due to infections or allergies. This can lead to symptoms such as a congested nose, high fever, and greenish mucus. While sinusitis often resolves on its own, untreated sinusitis can result in serious complications. These complications can include eye issues like cellulitis or abscesses, bone infections such as osteomyelitis, and even serious brain conditions like meningitis or abscesses.

Chronic sinusitis can also worsen respiratory problems like asthma or COPD. Therefore, it's important to monitor symptoms. You should seek a healthcare provider if sinusitis persists for more than 10 days, worsens, or causes severe pain. Treatment may involve antibiotics, decongestants, or surgery, depending on the severity of the condition.