Blocked or runny nose

Category: Head, Eyes, Ears, Nose & Throat · All head & senses symptoms

What it can feel like

A blocked or runny nose means the nasal lining is swollen or producing excess mucus — breathing through the nose feels obstructed, and there may be sneezing, reduced smell and a drip down the back of the throat. Colds cause most cases and settle in about a week.

Possible causes

A symptom can have many causes, and most are not serious. The lists below group conditions this symptom can be associated with — common causes first. They are possibilities to discuss with a clinician, not a diagnosis.

Common causes

Nasal symptoms can be associated with viral colds, hay fever and other allergies (dust, animals, pollen), irritants such as smoke and strong scents, and hormonal changes including pregnancy rhinitis.

Other possible causes

Persistent one-sided blockage can be associated with a deviated septum, nasal polyps, or a foreign body in a child. Blockage lasting months with crusting or bleeding can occasionally be associated with growths in the nose or sinuses.

Red flags — when to seek help promptly

One-sided blockage with blood-stained discharge that persists
A child with one-sided foul-smelling discharge — likely foreign body
Nasal blockage with swelling of the eye or forehead, or eye pain — urgent
Clear watery drip from one nostril after a head injury — urgent

What a clinician may do

A clinician will examine inside the nose and ask about pattern, triggers and seasonality. Allergy management and nasal steroid sprays address most chronic cases; persistent one-sided or structural problems lead to ENT referral and sometimes a nasal camera examination or scan.

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Frequently asked questions

Why is one nostril always more blocked?

At any moment one side of the nose is naturally more swollen — the nasal cycle alternates sides every few hours — and a bent septum exaggerates it. Blockage that is fixed on one side, especially with blood-stained discharge, is the pattern that needs examining.

Can nasal sprays make congestion worse?

Decongestant sprays can, if used for more than a few days — the lining rebounds and swells more (rhinitis medicamentosa). Steroid sprays work differently and are designed for sustained use; your clinician or pharmacist can help you switch safely.

Related symptoms — Head, Eyes, Ears, Nose & Throat

Bad breath (halitosis)Bleeding gums Blocked ear feeling Blurred vision Difficulty swallowing Discharge from the ear

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Please note: This page is educational information about a symptom. A symptom alone cannot diagnose any condition, and the causes listed here are possibilities, not a diagnosis. If you are worried about a symptom — especially one that is new, severe, getting worse or not going away — please see your own clinician, who can examine you and arrange tests. In an emergency, call your local emergency number.