Sinus pressure headaches happen when the small drainage channels connecting your sinuses to your nasal cavity become blocked, trapping mucus and creating a painful buildup of pressure behind your cheeks, forehead, or eyes. The blockage is usually caused by swelling of the sinus lining from infection, allergies, or irritants, but structural issues and even changes in atmospheric pressure can also be responsible. Importantly, about 55% of people who believe they have a sinus headache actually have a migraine, so understanding the real causes helps you get the right treatment.
How Sinus Pressure Builds Up
Your skull contains four pairs of air-filled cavities called paranasal sinuses, located behind your forehead, cheekbones, nose bridge, and deep behind the nasal cavity. These sinuses are lined with a thin membrane that constantly produces mucus. Tiny hair-like cells sweep that mucus toward narrow openings called ostia, which drain into the nasal cavity. Under normal conditions, this system clears itself continuously and you never feel a thing.
When something causes the tissue around those drainage openings to swell, the exits close off. The glands inside the sinus keep producing mucus with nowhere for it to go, and the pooling fluid creates increasing pressure against the rigid walls of the sinus cavity. That pressure activates pain-sensing nerves in the sinus lining, producing the deep, aching sensation you feel across your face. The location of the pain depends on which sinuses are blocked: forehead pressure points to the frontal sinuses, cheek pain to the maxillary sinuses, and pain between the eyes to the ethmoid sinuses.
Viral and Bacterial Infections
The most common trigger for sinus pressure is a viral upper respiratory infection, the ordinary cold. Cold viruses inflame the nasal and sinus membranes, causing enough swelling to partially or fully block the ostia. Most sinus pressure that accompanies a cold resolves on its own within 7 to 10 days as the viral infection clears.
Bacterial sinusitis develops in only about 0.5% to 2% of all upper respiratory infections. It typically follows a pattern: cold symptoms either persist beyond 10 days without improvement, or they start getting better and then suddenly worsen again (sometimes called “double worsening”). When bacteria do take hold, the trapped mucus becomes an ideal breeding ground, and the resulting infection intensifies the swelling, thickens the discharge, and produces more severe facial pain. Roughly one-third of people with acute sinus symptoms have a bacterial cause rather than a purely viral one.
Allergies and Histamine
Allergic rhinitis is the second major driver of sinus pressure. When you inhale an allergen like pollen, dust mites, mold spores, or pet dander, your immune system treats it as a threat. Immune cells in the nasal lining release a burst of chemical messengers, most notably histamine, within seconds. Histamine triggers a chain reaction: blood vessels in the sinus lining dilate, causing congestion; the vessel walls become leaky, allowing fluid to seep into surrounding tissue and creating swelling; and mucus glands ramp up production. The combination of swollen tissue and excess mucus narrows or seals the sinus drainage openings, producing the same pressure buildup you’d get from an infection.
Because allergic reactions recur every time you encounter the trigger, people with untreated allergies often experience sinus pressure in seasonal patterns (spring and fall for pollen) or constantly if they’re reacting to indoor allergens like dust or pet dander. The genetic tendency to develop these reactions means sinus pressure headaches from allergies often run in families.
Irritants That Inflame Without Allergies
You don’t need allergies or an infection to develop sinus pressure. Nonallergic rhinitis causes the same nasal and sinus swelling through direct irritation of the lining. Common triggers include cigarette smoke, strong perfumes, smog, exhaust fumes, and chemical fumes encountered in workplaces like construction sites. Even cleaning products, compost, and heavily polluted outdoor air can set it off. The sinus lining reacts to these irritants with inflammation and excess mucus, blocking drainage in exactly the same way allergies do, just through a different pathway. This type of sinus pressure can be confusing because allergy tests come back negative, leading people to wonder why they keep getting congested.
Structural Blockages
Sometimes the problem is physical rather than inflammatory. A deviated septum, where the wall between the two sides of the nose is significantly off-center, can narrow the drainage pathway on one side. Nasal polyps, which are painless, noncancerous growths that develop in the sinus or nasal lining, can grow large enough to physically block the ostia and trap mucus. Polyps are strongly associated with repeated sinus infections and chronic sinus pressure.
Less well-known are anatomical variations in the sinus bones themselves. Some people have extra air cells, called Haller cells, that form along the floor of the eye socket near the opening of the maxillary (cheek) sinus. Research has found a strong correlation between the presence of Haller cells and chronic sinus inflammation. In one study, Haller cells altered the drainage pathway of the maxillary sinus in 40 out of 42 patients examined. These variations are present from birth and can explain why some people seem prone to sinus pressure headaches their whole lives without an obvious allergic or infectious cause.
Barometric Pressure Changes
If your sinus pressure gets worse during flights, weather fronts, or trips to higher elevations, physics is partly to blame. Your sinuses are rigid, air-filled chambers, and the air inside them follows Boyle’s Law: when outside pressure drops (as it does when you ascend in altitude or a storm system moves in), the air trapped inside the sinus expands. Normally, that expanding air escapes through the ostia and pressure equalizes painlessly.
But if your sinus openings are even slightly narrowed from a mild cold, allergies, or swelling, the air can’t equalize. On the way up, expanding air creates positive pressure that pushes painfully against the sinus walls. On the way down, the reverse happens: contracting air creates a vacuum effect that pulls on the lining. This condition, known as barosinusitis, is especially common in frequent flyers or divers who happen to have any baseline nasal congestion.
Chronic vs. Acute Sinus Pressure
Acute sinusitis is a short-lived episode, usually linked to a cold, that resolves within a few weeks. Chronic sinusitis is defined as symptoms lasting 12 weeks or longer, even with treatment. The causes of chronic sinus pressure overlap with the acute causes listed above but tend to involve ongoing factors: persistent allergies, nasal polyps, structural abnormalities, or recurring infections that never fully resolve. Chronic cases often require imaging (typically a CT scan) or direct examination of the nasal passages to confirm that the sinus lining is actually inflamed, because long-lasting facial pressure has many possible explanations beyond the sinuses.
When It’s Actually a Migraine
This is one of the most important things to know about sinus pressure headaches: more than half the time, they aren’t caused by your sinuses at all. A systematic review pooling data from eight studies found that 55% of people who reported sinus headaches were clinically diagnosed with migraines instead. When probable migraines and tension-type headaches were included, that number rose to 65%.
Migraines can cause facial pressure, nasal congestion, and even a runny nose, which is why the confusion is so common. The key differences are that migraines tend to be one-sided, throb or pulse, worsen with physical activity, and come with sensitivity to light or sound. True sinus pressure headaches almost always involve thick, discolored nasal discharge and tend to produce a constant, deep ache rather than a throbbing sensation. If you’ve been treating “sinus headaches” for months without relief, especially if over-the-counter decongestants don’t help, the underlying cause may be neurological rather than sinus-related.