What Causes Runny Nose? Common & Serious Causes Explained
Runny nose can be caused by Sinusitis, Allergic Rhinitis (Hay Fever), Common Cold and other conditions. Learn which causes are serious, which are benign, and when to seek urgent medical evaluation.
Updated March 27, 2026
Runny nose has multiple causes, ranging from benign to serious. The most common include Sinusitis, Allergic Rhinitis (Hay Fever), Common Cold. Sinusitis is inflammation of the sinuses, often following a cold or allergy. It causes facial pain, nasal congestion, thick nasal discharge, and reduced sense of smell. Acute sinusitis lasts up to 4 weeks; chronic sinusitis persists over 12 weeks.
Clinical Context
The causes of runny nose range from benign to serious. Identifying the underlying cause requires clinical evaluation. Common causes include Sinusitis, Allergic Rhinitis (Hay Fever), Common Cold, Measles, and others.
Clinical Pathway
Runny nose — Symptom HubSymptomSinusitis — Full Condition GuidePrimary CauseSinusitis — Differential DiagnosisDifferentialAllergic Rhinitis (Hay Fever) vs. Sinusitis — Comparisonvs.Allergic Rhinitis (Hay Fever) — Full Condition GuideCauseCommon Cold — Full Condition GuideCauseMeasles — Full Condition GuideCauseFrequently Asked Questions
Why do I have runny nose? common & serious causes explained?+
Runny nose has multiple causes, ranging from benign to serious. The most common include Sinusitis, Allergic Rhinitis (Hay Fever), Common Cold. Sinusitis is inflammation of the sinuses, often following a cold or allergy. It causes facial pain, nasal congestion, thick nasal discharge, and reduced sense of smell. Acute sinusitis lasts up to 4 weeks; chronic sinusitis persists over 12 weeks.
What is the most common cause of runny nose?+
Common causes include Sinusitis, Allergic Rhinitis (Hay Fever), Common Cold. The most likely cause depends on age, associated symptoms, and medical history.
When is runny nose dangerous?+
Seek medical attention if runny nose is persistent, worsening, sudden in onset, or accompanied by other concerning symptoms.
Can runny nose be caused by stress or anxiety?+
Yes — psychological stress can contribute to many physical symptoms, but organic causes should be excluded by a healthcare provider.
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