Sinus and allergy

Is It Really Sinusitis?

Sinus pressure, blocked nose and post-nasal drip explained.

A clear guide to sinus pressure, blocked nose and post-nasal drip, and how sinusitis, allergy, rhinitis, nasal polyps and migraine can overlap.

Sinus and allergy7 min readGeneral informationUpdated May 2026

Sinus symptoms often overlap with allergy, rhinitis, nasal polyps and headache disorders.

“Sinus” is often a symptom label

People use it for facial pressure, blocked nose, mucus, headache, post-nasal drip or reduced smell.

Timing helps

Short symptoms after a cold behave differently from symptoms lasting many weeks or months.

Allergy has clues

Sneezing, itch, watery eyes and predictable triggers may point towards allergic rhinitis.

What sinusitis actually means

People often say “my sinuses are playing up” when they feel facial pressure, mucus at the back of the throat, a blocked nose, headache, reduced smell or a heavy feeling behind the eyes. Sometimes that is sinusitis. Sometimes it is allergy, rhinitis, migraine, nasal polyps, dental disease or several things at once.

The sinuses are air-filled spaces in the face and forehead that drain into the nose. Sinusitis means inflammation affecting the sinuses and their drainage pathways. The lining swells, mucus does not drain as easily and the nose can feel blocked or full.

Acute sinusitis commonly follows a cold or flu. Chronic rhinosinusitis is a longer inflammatory pattern, usually discussed when symptoms persist for 12 weeks or more. Chronic symptoms are not simply “an infection that needs repeated antibiotics”; they can involve inflammation, allergy, polyps, asthma, anatomy, environmental irritation and the way the nose drains.

Why allergy, rhinitis and polyps can feel like “sinus”

Allergic rhinitis can cause sneezing, itch, watery eyes, runny nose, blocked nose and cough from post-nasal drip. These symptoms can sit alongside facial pressure and reduced smell, so it is easy for allergy to be mistaken for sinus infection.

Non-allergic rhinitis can also cause blockage and dripping without a classic pollen or dust-mite allergy. Triggers can include cold air, strong smells, smoke, pollution, alcohol, spicy food or changes in humidity. Nasal polyps can create a more persistent pattern: blocked nose, post-nasal drip, reduced smell or taste and snoring.

Facial pressure is not always sinusitisPressure around the cheeks, forehead or eyes can come from sinus inflammation, but headache disorders, jaw problems, dental disease and muscle tension can feel similar. This is one reason examination matters.

Watercolour panels showing allergy, sneezing, nasal inflammation and symptom assessment — Timing, triggers, mucus, smell and examination help separate sinus inflammation from allergy or other causes.

Patterns that help separate the causes

After a coldBlocked nose, coloured mucus and facial pressure after a viral illness may fit acute sinusitis, especially if symptoms worsen after initially improving.

Seasonal or trigger-relatedSneezing, itch, watery eyes and symptoms around pollen, animals, mould or dust suggest allergy.

Long-lasting blockage and smell lossSymptoms lasting months, especially with reduced smell or polyps, may fit chronic rhinosinusitis or chronic rhinitis.

Mostly headache or pressureIf nasal symptoms are minor, migraine, tension-type headache, jaw or dental causes may need consideration.

A clinician may ask about asthma, aspirin/anti-inflammatory sensitivity, repeated infections, previous surgery, dental symptoms, occupation, smoking or vaping exposure, and how symptoms affect sleep and work. Examination may include looking inside the nose and, in some cases, nasal endoscopy or imaging if the history and examination suggest it is needed.

When to get reviewed

Arrange advice if symptoms last longer than expected, keep returning, affect sleep or work, or are associated with reduced smell, polyps, asthma, recurrent infections or one-sided symptoms. A review is also sensible if over-the-counter treatments are not helping or are being used repeatedly without a clear plan.

Seek urgent advice for severe featuresUrgent assessment is needed for swelling around the eye, visual changes, severe or rapidly worsening headache, confusion, neck stiffness, high fever, facial swelling, or if you feel seriously unwell.

Sources and further reading

This article is general public information and was written using UK, European and well-regarded US sources. It should not replace personal medical advice.

SinusitisNHS
Chronic sinusitis managementNICE Clinical Knowledge Summaries
EPOS 2020 executive summaryRhinology / EPOS
Allergic rhinitisNHS
Nasal polypsNHS
Hay fever and allergic rhinitisAllergy UK