Constant catarrh is almost always caused by ongoing inflammation or irritation of the mucous membranes lining your nose and throat. The most common culprits are allergies, chronic sinus inflammation, and a form of acid reflux that reaches the throat. In many cases, more than one factor is at work simultaneously, which is why the problem can feel so stubborn.
How Mucus Overproduction Works
Your nose and throat are lined with membranes that produce mucus constantly. This is normal and healthy: mucus traps dust, bacteria, and other particles so they can be swept away. Problems start when something triggers those membranes to swell and ramp up production beyond what your body can clear.
During an infection, bacteria or viruses cause inflammation that signals the glands in your airway to produce more mucus. That mucus thickens as immune cells flood in to fight the infection, which triggers yet more mucus production in a self-reinforcing cycle. With allergies, the process is different but the result is similar: your immune system releases histamine in response to something harmless like pollen or dust mites, and histamine causes the nasal membranes to swell and the glands to overproduce. When the trigger doesn’t go away, neither does the catarrh.
Allergic and Non-Allergic Rhinitis
Rhinitis, meaning inflammation of the nasal lining, is one of the most common reasons for persistent catarrh. It comes in two forms that feel almost identical but have different underlying mechanisms.
Allergic rhinitis is driven by an immune overreaction. Seasonal cases are triggered by pollens, while year-round cases typically involve dust mites, mold spores, or animal dander. Over time, repeated allergen exposure actually rewires the nerve endings in your nasal lining, making them increasingly sensitive. This is why allergies can seem to worsen over the years: your nasal neurons become primed to react to smaller and smaller amounts of the trigger.
Non-allergic rhinitis (sometimes called vasomotor rhinitis) produces the same congestion and dripping but without any identifiable allergen. Triggers include changes in weather or temperature, cigarette smoke, strong perfumes, barometric pressure shifts, and even spicy food. Allergy testing comes back negative, which can be frustrating when you’re clearly producing too much mucus. This type accounts for a large share of chronic rhinitis cases and is diagnosed by ruling out allergies and infection.
Chronic Sinusitis
When sinus inflammation persists for 12 weeks or longer, it qualifies as chronic rhinosinusitis. About 2.1% of U.S. adults meet the symptom criteria for this condition at any given time. The hallmark symptoms are nasal congestion, discolored mucus draining from the front or back of the nose, a reduced sense of smell, and facial pressure or pain. Additional symptoms can include ear fullness, fatigue, cough, bad breath, and headache.
Chronic sinusitis can develop after a lingering infection, as a complication of untreated allergies, or alongside nasal polyps (soft growths inside the sinuses that block drainage). The inflamed, swollen sinus lining traps mucus that would normally drain freely, creating a constant sensation of catarrh that pools in the throat.
Silent Reflux
One of the most overlooked causes of constant catarrh is laryngopharyngeal reflux, often called “silent reflux” because it doesn’t always cause the heartburn people associate with acid reflux. In this condition, stomach acid and digestive enzymes travel up past the esophagus and reach the throat. The throat lining lacks the protective barriers that the esophagus has, and it can’t wash the acid away as effectively, so even a small amount of reflux causes disproportionate irritation.
That irritation triggers excess mucus production and disrupts the normal mechanisms that clear mucus and trapped infections from the throat and sinuses. The result is a cycle of throat clearing, the feeling of something stuck in your throat, excessive phlegm, and sometimes hoarseness or a chronic cough. Many people with silent reflux spend years treating suspected allergies or sinus problems before the real cause is identified.
Structural Problems in the Nose
Physical obstructions inside the nose can impair mucus drainage and create a persistent feeling of congestion. The most common structural issue is a deviated nasal septum, where the wall between your nostrils is significantly off-center. The second most common is turbinate hypertrophy, an enlargement of the small, shelf-like structures inside each nostril that normally regulate airflow and moisture.
Turbinates swell in response to allergic and non-allergic rhinitis, and over time this swelling can become semi-permanent as the tissue thickens. A deviated septum combined with enlarged turbinates narrows the airway enough that mucus pools rather than draining, giving you the sensation of constant catarrh even when mucus production itself is relatively normal.
Medication Side Effects
Certain medications can worsen catarrh by slowing the tiny hair-like structures (cilia) that sweep mucus out of your airways. Aspirin, some sedatives, certain anesthetic agents, and a class of drugs that block nerve signals to glands (commonly used for bladder problems, motion sickness, and some respiratory conditions) have all been shown to depress the mucus clearance system. If your catarrh started or worsened around the time you began a new medication, that timing is worth noting.
Managing Persistent Catarrh
Because treatment depends entirely on the cause, the first step is identifying which of the above factors applies to you. Allergic rhinitis responds to avoiding triggers where possible and using steroid nasal sprays or antihistamines. Non-allergic rhinitis is managed similarly with nasal sprays, though antihistamines are less effective. Chronic sinusitis may require a longer course of nasal steroids and, in some cases, surgery to improve drainage. Silent reflux typically improves with dietary changes and medications that reduce stomach acid.
One self-care measure that helps across nearly all causes is saline nasal irrigation. Rinsing the nasal passages with salt water washes out mucus, allergens, and inflammatory substances while improving the function of the cilia that keep mucus moving. A meta-analysis found that hypertonic saline (slightly saltier than body fluids) was more effective at reducing nasal secretions than standard isotonic saline. Squeeze bottles and neti pots are both widely available, and the technique is straightforward once you’ve done it a few times.
Symptoms That Need Prompt Attention
Most catarrh is a nuisance, not a danger. But certain patterns warrant an urgent referral to an ear, nose, and throat specialist. The key red flag is unilateral symptoms: blockage, pain, or discharge affecting only one side of the nose. Blood-stained mucus from one nostril, especially combined with one-sided congestion or facial pain, should always be investigated. These patterns can indicate nasal or sinus tumors, which are rare but important to catch early. Symmetrical catarrh affecting both sides equally is far less concerning and points toward the inflammatory and reflux-related causes described above.