Sinusitis: Symptoms, Causes & Treatment Guide

What Are the Paranasal Sinuses?

The paranasal sinuses are air-filled cavities in the skull bones surrounding the nose. They produce mucus that helps humidify inhaled air and trap airborne particles. The four pairs of sinuses are the maxillary sinuses (in the cheekbones), frontal sinuses (in the forehead), ethmoid sinuses (between the eyes), and sphenoid sinuses (behind the nose).

The paranasal sinuses are located near the nose and connect to the nasal cavity through small openings. These air-filled spaces in the skull bones serve several important functions in the respiratory system and facial structure. Understanding their anatomy helps explain why sinusitis develops and causes the symptoms it does.

The sinuses are lined with the same type of mucous membrane found in the nasal cavity. This membrane contains tiny hair-like structures called cilia that help move mucus toward the nasal passages for drainage. When functioning normally, this system keeps the sinuses clean and healthy. However, when the drainage pathways become blocked, problems can develop.

The mucus produced by the sinuses plays a vital role in respiratory health. It humidifies the air we breathe, preventing the delicate lung tissues from drying out. Additionally, the mucus traps dust, bacteria, viruses, and other airborne particles, providing an important first line of defense against respiratory infections.

The Four Types of Sinuses

Each pair of sinuses has a specific location and characteristics. The maxillary sinuses are the largest, located in the cheekbones below the eyes. They are prone to infection because their drainage openings are positioned at the top rather than the bottom, making natural drainage difficult.

The frontal sinuses are located in the forehead above the eyes. Infections here often cause headaches and pain in the forehead area. The ethmoid sinuses are a collection of small air cells located between the eyes, and they develop earliest in life. The sphenoid sinuses are the deepest, located behind the nose in the center of the skull.

Sinus size varies considerably between individuals. In newborns, the sinuses are very small or not yet developed. They grow gradually throughout childhood and adolescence, typically reaching their full size during the teenage years. The ethmoid sinuses develop first, while the frontal sinuses are usually the last to fully develop.

What Is Sinusitis and How Does It Develop?

Sinusitis (rhinosinusitis) is inflammation of the paranasal sinuses, most commonly developing as a complication of a cold. When nasal membranes swell from a viral infection, the sinus drainage pathways become blocked, allowing fluid and mucus to accumulate. If bacteria then grow in this environment, symptoms can worsen.

Sinusitis typically begins when a viral upper respiratory infection, such as the common cold, causes the mucous membranes in the nose and sinuses to swell. This swelling narrows or blocks the small openings through which the sinuses normally drain into the nasal cavity. When these drainage pathways are obstructed, mucus and fluid accumulate in the sinuses rather than draining away normally.

The accumulated fluid creates an ideal environment for bacteria to grow. Although most sinusitis cases remain viral and resolve on their own, approximately 2-10% develop secondary bacterial infection. When bacterial infection occurs, symptoms often become more severe and may require antibiotic treatment.

It's important to understand that having fluid visible on imaging or experiencing symptoms does not automatically indicate bacterial infection. The vast majority of people with sinusitis symptoms have viral infections that will improve without antibiotics. This distinction is crucial because overuse of antibiotics contributes to antibiotic resistance, a growing global health concern.

Acute vs Chronic Sinusitis

Sinusitis is classified based on how long symptoms persist. Acute sinusitis lasts less than 4 weeks and is the most common form. It usually develops after a cold and resolves with or without treatment. Subacute sinusitis lasts 4-12 weeks and represents a transitional stage. Chronic sinusitis is defined as symptoms persisting for 12 weeks or longer despite treatment attempts.

Recurrent acute sinusitis describes a pattern of four or more acute episodes per year, with symptom-free periods between episodes. Each form may have different underlying causes and requires different treatment approaches.

Sinusitis in Children

While colds and runny noses are extremely common in children, sinusitis requiring treatment is less common in younger children. This is partly because their sinuses are still developing. When children do develop sinusitis, it most commonly affects the ethmoid sinuses, which can cause swelling and redness around the nose and eyes.

What Are the Symptoms of Sinusitis?

The main symptoms of sinusitis include facial pain or pressure (often worse on one side), nasal congestion, thick discolored nasal discharge, reduced or lost sense of smell, and postnasal drip. Additional symptoms may include headache, tooth pain in the upper jaw, fatigue, fever, and bad breath.

Sinusitis produces a characteristic pattern of symptoms that typically develops during or shortly after a cold. Understanding these symptoms helps distinguish sinusitis from other conditions and identify when medical attention may be needed. The symptoms result from inflammation and fluid accumulation in the sinuses, as well as the body's immune response to infection.

The most distinctive symptom is facial pain or pressure, which is often described as a dull, constant ache rather than sharp pain. This discomfort typically worsens when bending forward or lying down, as these positions increase pressure in the sinuses. The location of pain often corresponds to which sinuses are affected - maxillary sinusitis causes cheek pain, frontal sinusitis causes forehead pain, and ethmoid sinusitis causes pain between the eyes.

Nasal symptoms are nearly universal in sinusitis. Congestion makes breathing through the nose difficult or impossible, and thick nasal discharge is common. The discharge may be clear, white, yellow, or green - contrary to popular belief, the color alone does not reliably indicate bacterial versus viral infection. Many people also experience postnasal drip, where mucus drains down the back of the throat, causing throat irritation and cough.

Common Sinusitis Symptoms

• Facial pain or pressure: Usually worse on one side, increases when bending forward
• Nasal congestion: Difficulty breathing through the nose
• Thick nasal discharge: May drain from nose or down back of throat
• Reduced sense of smell: Called hyposmia or anosmia if complete
• Tooth pain: Especially upper back teeth, due to proximity to maxillary sinuses
• Fever: More common with bacterial infection
• Fatigue and malaise: General feeling of being unwell
• Bad breath: From infected discharge

Symptoms in Children

Children with sinusitis may present differently than adults. In addition to the typical symptoms, children may develop swelling and redness around the eyes, particularly with ethmoid sinusitis. Young children may be irritable and have difficulty feeding. Cough, especially at night, is often a prominent symptom in children.

When Symptoms Suggest Something More Serious

While most sinusitis cases are mild and self-limiting, certain symptoms require urgent medical attention. These warning signs may indicate that infection is spreading beyond the sinuses or that a more serious condition is present.

When Should You See a Doctor for Sinusitis?

See a doctor if sinusitis symptoms persist beyond 10 days without improvement, if symptoms initially improve then worsen again, or if you have severe symptoms including high fever (above 39C/102F), severe facial pain, or signs of complications. Most cases resolve without medical intervention within 7-10 days.

The majority of people with sinusitis do not need to see a doctor. Symptoms typically improve within 7-10 days as the viral infection runs its course and the sinuses begin to drain normally again. Home care measures are usually sufficient to manage symptoms during this time.

However, certain situations warrant medical evaluation. The most important indicator is the duration and pattern of symptoms. If symptoms persist beyond 10 days without any improvement, medical evaluation is appropriate. Similarly, if symptoms initially improve but then worsen again (a pattern sometimes called "double sickening"), this may indicate bacterial superinfection.

The severity of symptoms also matters. Moderate symptoms lasting several days may not require medical attention, but severe symptoms - particularly high fever combined with intense facial pain - should prompt earlier evaluation. Your overall health status is also relevant; people with weakened immune systems or certain chronic conditions may need earlier medical attention.

When to Contact a Healthcare Provider

• Symptoms persist beyond 10 days without improvement
• Symptoms improve initially, then worsen significantly
• Fever above 39C (102F) with facial pain
• Severe symptoms that don't respond to home treatment
• Multiple episodes of acute sinusitis per year
• Symptoms accompanied by vision changes or severe headache

Urgent Symptoms Requiring Immediate Attention

Some symptoms indicate potentially serious complications that require urgent medical care. Swelling around the eye, particularly if accompanied by redness, pain, or vision changes, may indicate orbital cellulitis - a serious infection requiring immediate treatment. Severe headache with neck stiffness could indicate meningitis. Any neurological symptoms such as confusion or facial weakness require emergency evaluation.

What Can You Do at Home to Treat Sinusitis?

Effective home treatments for sinusitis include saline nasal irrigation (proven effective in clinical studies), using a humidifier or steam inhalation, sleeping with head elevated, staying well hydrated, and taking over-the-counter pain relievers. Decongestant nasal sprays can provide short-term relief but should not be used longer than 3-5 days.

Self-care measures form the foundation of sinusitis treatment for most cases. These approaches help relieve symptoms, promote natural drainage, and support the body's healing process. Many of these methods have been validated in clinical studies and are recommended in medical guidelines. The goal is to reduce inflammation, thin mucus, and restore normal sinus drainage.

Consistency with self-care measures often matters more than any single treatment. Using multiple approaches together - such as nasal irrigation combined with adequate hydration and rest - typically produces better results than relying on any single intervention. Most people notice improvement within a few days of starting comprehensive self-care.

Saline Nasal Irrigation

Saline nasal irrigation is one of the most effective and well-studied treatments for sinusitis symptoms. This technique involves flushing the nasal passages with a salt water solution, which helps remove thick mucus, reduce inflammation, and wash away irritants and infectious agents. Multiple clinical trials have demonstrated its effectiveness.

You can perform nasal irrigation using a neti pot, squeeze bottle, or bulb syringe. Always use distilled, sterile, or previously boiled and cooled water - never tap water, which may contain harmful organisms. Commercial saline packets or isotonic saline solutions are available at pharmacies. Irrigation can be performed 1-2 times daily during acute sinusitis.

Additional Self-Care Measures

• Sleep with head elevated: Use an extra pillow to reduce sinus swelling during sleep
• Stay active when possible: Being upright and moving around helps reduce nasal and sinus swelling
• Avoid smoking: Smoke irritates mucous membranes and impairs ciliary function
• Use steam: Inhaling steam from a bowl of hot water or shower can help loosen mucus
• Stay hydrated: Adequate fluid intake helps thin mucus secretions
• Apply warm compresses: A warm, damp towel over the face may relieve pain

Over-the-Counter Medications

Decongestant nasal sprays (such as oxymetazoline or xylometazoline) can quickly reduce nasal swelling and improve breathing. However, they should be used for no more than 3-5 days, as prolonged use can cause rebound congestion (rhinitis medicamentosa) where the medication actually worsens congestion.

Pain relievers such as acetaminophen (paracetamol) or ibuprofen can help manage facial pain, headache, and fever. Follow package directions and consider any contraindications for your individual health situation.

Corticosteroid nasal sprays can help reduce inflammation, particularly if allergies contribute to your symptoms. These are available over-the-counter in many countries and can be used longer-term than decongestant sprays.

Is Sinusitis Contagious?

Sinusitis itself is not contagious, but the viruses that cause it (such as cold viruses) spread easily between people through respiratory droplets. When someone with viral sinusitis coughs or sneezes, they can spread the virus to others, who may then develop a cold that could progress to sinusitis. Bacterial sinusitis is generally not contagious.

This is an important distinction that many people find confusing. The sinus inflammation itself cannot be transmitted from person to person. However, the underlying viral infection that typically causes acute sinusitis is highly contagious. When an infected person coughs, sneezes, or even talks, they release tiny droplets containing virus particles that others can inhale or pick up from contaminated surfaces.

If you contract a cold virus from someone with sinusitis, you may develop cold symptoms - and your cold may or may not progress to sinusitis depending on various factors including your individual anatomy, immune function, and whether you have risk factors like allergies. Not everyone who catches the same cold virus will develop sinusitis; many will have only mild cold symptoms.

Good hand hygiene remains the most effective way to prevent the spread of respiratory viruses. Wash hands frequently, avoid touching your face, and stay home when you're sick to avoid spreading infection to others.

How Is Sinusitis Diagnosed?

Sinusitis is typically diagnosed based on symptoms and physical examination. The doctor will examine the nose, mouth, throat, and ears to look for signs of inflammation and discharge. Imaging tests like CT scans are usually reserved for cases that don't respond to treatment, are recurrent, or when complications are suspected.

In most cases, sinusitis can be diagnosed based on the characteristic pattern of symptoms and a physical examination. The doctor will ask about your symptoms, their duration, and their severity. They will examine your nasal passages, looking for signs of inflammation, swelling, and discharge. The examination may include looking at the back of your throat for postnasal drip and checking your ears, as the symptoms can sometimes overlap with middle ear conditions.

For uncomplicated acute sinusitis, no additional tests are typically needed. The diagnosis is made clinically, meaning it is based on your symptoms and the doctor's examination findings rather than on laboratory or imaging tests.

Additional Tests When Needed

In certain situations, additional investigations may be warranted. If your doctor suspects complications, needs to rule out other conditions, or if your sinusitis hasn't responded to initial treatment, further testing may be recommended.

Nasal endoscopy involves inserting a thin, flexible tube with a camera into the nose to visualize the nasal passages and sinus openings directly. This procedure is typically performed by an ENT specialist and provides detailed information about the condition of the nasal structures.

CT scan (computed tomography) can show the extent of sinus inflammation, reveal structural abnormalities, and help identify complications. CT imaging is usually reserved for chronic sinusitis, recurrent sinusitis, cases not responding to treatment, or when surgery is being considered.

How Is Sinusitis Treated?

Treatment depends on the cause and severity. Most cases resolve with supportive care including saline irrigation, decongestants, and pain relievers. Antibiotics are only recommended for bacterial sinusitis - typically if symptoms persist beyond 10 days, are severe, or worsen after initial improvement. Chronic sinusitis may require corticosteroid nasal sprays, prolonged antibiotics, or surgery.

The approach to treating sinusitis depends on several factors: whether it's acute or chronic, the severity of symptoms, the likely cause (viral vs bacterial), and the patient's overall health. The majority of acute sinusitis cases are viral and will resolve without specific treatment. Medical guidelines emphasize avoiding unnecessary antibiotics while ensuring patients receive appropriate care when needed.

Supportive care forms the foundation of treatment for most sinusitis cases. This includes the self-care measures discussed earlier: saline nasal irrigation, adequate hydration, rest, and symptomatic treatment with decongestants and pain relievers. For many people, these measures are all that's needed.

When Antibiotics Are Appropriate

Antibiotics are only effective against bacterial infections and have no benefit for viral sinusitis. Current medical guidelines recommend considering antibiotics in the following situations:

• Symptoms persist beyond 10 days without improvement
• Severe symptoms: high fever (above 39C/102F) combined with purulent nasal discharge for at least 3-4 consecutive days
• "Double worsening": symptoms that improve initially then significantly worsen

When antibiotics are indicated, amoxicillin or amoxicillin-clavulanate is typically the first-line choice. Treatment duration is usually 5-10 days depending on severity and response. It's important to complete the full course as prescribed, even if symptoms improve before finishing the medication.

Sinus Irrigation (Sinus Lavage)

In cases where sinusitis doesn't respond to standard treatment, a doctor may perform therapeutic sinus irrigation. This procedure, done under local anesthesia, involves flushing the sinuses with saline solution to remove accumulated mucus and pus. It can provide symptom relief and also allows the doctor to collect samples for bacterial culture.

Surgery for Sinusitis

Some patients with chronic sinusitis or recurrent acute sinusitis may benefit from surgery. Functional endoscopic sinus surgery (FESS) is the most common procedure. The surgeon uses an endoscope and small instruments inserted through the nose to widen the sinus drainage pathways, remove polyps if present, and clear any obstruction.

Surgery is typically considered when chronic sinusitis has not responded to medical treatment, when nasal polyps are obstructing the sinuses, or when anatomical abnormalities are contributing to recurrent infections. The procedure is usually done on an outpatient basis, and recovery typically takes 1-2 weeks.

What Causes Sinusitis and Who Is at Risk?

Sinusitis most commonly develops following viral upper respiratory infections (colds). Risk factors include allergies, nasal polyps, deviated septum, smoking, weakened immune system, and dental infections. Anything that blocks normal sinus drainage or impairs mucociliary clearance increases the risk of developing sinusitis.

Understanding the causes and risk factors for sinusitis can help in both prevention and treatment. The fundamental problem in sinusitis is impaired drainage of the sinuses, which allows fluid and potentially bacteria to accumulate. Various factors can contribute to this drainage impairment.

The most common trigger for acute sinusitis is a viral upper respiratory infection - the common cold. The cold virus causes inflammation and swelling of the nasal and sinus membranes, which narrows the sinus drainage openings. In most cases, the inflammation resolves as the viral infection clears, and normal drainage resumes. However, in some cases, the blocked sinuses become secondarily infected with bacteria.

Risk Factors for Sinusitis

• Allergies (allergic rhinitis): Allergies cause chronic inflammation that can impair sinus drainage
• Nasal polyps: Soft growths that can physically block sinus openings
• Deviated septum: A crooked nasal septum can obstruct drainage on one side
• Smoking: Damages the cilia that clear mucus and causes chronic inflammation
• Environmental irritants: Air pollution, chemical fumes can cause inflammation
• Weakened immune system: Reduces ability to fight infections
• Dental infections: Upper tooth infections can spread to adjacent maxillary sinuses
• Previous respiratory infections: Recent cold or flu

Dental Infections and Sinusitis

An infection in an upper tooth can spread to the maxillary sinus because the roots of the upper molars are located very close to - or sometimes even within - the floor of the sinus. When this occurs, the resulting sinusitis typically affects only the sinus on the same side as the infected tooth.

Signs that sinusitis may have a dental origin include symptoms limited to one side, pain in the upper jaw, and particularly foul-smelling discharge. Treating the dental infection is essential for resolving the sinusitis in these cases.

What Are the Complications of Sinusitis?

Serious complications from sinusitis are rare but can include orbital cellulitis (infection spreading to the eye socket), meningitis, brain abscess, and bone infection. Warning signs include eye swelling/redness, vision changes, severe headache with stiff neck, and neurological symptoms. These require immediate emergency care.

While the vast majority of sinusitis cases resolve without complications, it's important to be aware of potential serious complications, particularly because the sinuses are located near critical structures including the eyes, brain, and major blood vessels. Recognizing warning signs allows for early intervention when needed.

Infection can potentially spread beyond the sinuses in several ways. The thin bony walls separating the sinuses from the orbit (eye socket) and cranial cavity can be penetrated by severe infection. Venous channels can also provide pathways for infection to spread. Fortunately, with modern antibiotic therapy, these complications have become much less common than they once were.

Potential Complications

Orbital complications occur when infection spreads from the ethmoid sinuses to the eye socket. Early stages (preseptal cellulitis) cause eyelid swelling but vision remains normal. More advanced infection (orbital cellulitis) causes eye pain, restricted eye movement, and vision changes. This is a medical emergency requiring immediate treatment.

Intracranial complications are rare but serious. These include meningitis (infection of the membranes surrounding the brain), brain abscess, and venous sinus thrombosis. Symptoms include severe headache, stiff neck, confusion, and other neurological changes.

Chronic sinusitis itself can be considered a complication when acute sinusitis fails to resolve and persists for 12 weeks or longer. Chronic sinusitis requires different treatment approaches and may significantly impact quality of life.

Sinusitis During Pregnancy

Pregnant women are more susceptible to sinusitis due to hormonal changes that cause nasal membrane swelling and a slightly weakened immune system. Most cases can be managed with saline irrigation and safe medications. Some decongestants should be avoided during pregnancy, so consult your healthcare provider before taking any medications.

During pregnancy, the body undergoes hormonal changes that cause swelling of mucous membranes throughout the body, including the nose and sinuses. This pregnancy-related nasal congestion (sometimes called "pregnancy rhinitis") can make pregnant women more susceptible to developing sinusitis when they catch a cold.

The immune system is also naturally slightly suppressed during pregnancy to prevent the body from rejecting the developing fetus. This can make respiratory infections more common and slower to resolve.

Managing sinusitis during pregnancy requires careful consideration of which treatments are safe. Saline nasal irrigation is completely safe and effective. Corticosteroid nasal sprays are generally considered safe and can help reduce inflammation. Acetaminophen (paracetamol) is the preferred pain reliever during pregnancy.

Some medications should be avoided or used with caution during pregnancy. Certain oral decongestants (particularly in the first trimester) and some antibiotics are not recommended. Always consult your doctor or midwife before taking any medication during pregnancy.