Why does a runny nose occur when having a cold?

Jul 18, 2025 Source: Cainiu Health

Dr. Ren Yi

Introduction

In general, runny nose with clear nasal discharge during a cold may be caused by factors such as nasal mucosal congestion and edema, increased secretion from nasal mucosal glands, viral colds, allergic rhinitis combined with a cold, or rhinovirus infection. It is recommended to seek medical attention promptly, identify the underlying cause, and undergo symptomatic treatment under a doctor's guidance. When experiencing a common cold, it is important to keep warm and avoid further exposure to cold, which could worsen symptoms.

Generally, runny nose with clear mucus during a cold may be caused by factors such as nasal mucosal congestion and edema, increased secretion from nasal mucosal glands, viral infection, allergic rhinitis combined with a cold, or rhinovirus infection. It is recommended to seek timely medical attention, identify the underlying cause, and undergo symptomatic treatment under a doctor's guidance. Detailed explanations are as follows:

1. Nasal mucosal congestion and edema: During a cold, the nasal mucosa becomes irritated, causing blood vessels to dilate and leading to mucosal swelling. This enhances the secretory function of submucosal glands, producing clear nasal discharge accompanied by nasal congestion and itching, which worsens with exposure to cold. Applying a warm towel compress to the nasal area can improve local blood circulation and reduce congestion and swelling. Massaging both sides of the nostrils can also help relieve nasal congestion and decrease the flow of clear nasal mucus.

2. Increased nasal mucosal gland secretion: A cold-induced nasal mucosal inflammation stimulates glands to secrete large amounts of mucus, forming clear nasal discharge. This helps flush pathogens and protect the nasal mucosa, typically decreasing as the cold improves. Drinking more warm water to keep nasal mucosa moist, avoiding forceful nose-blowing to prevent mucosal damage, and using normal saline to irrigate the nasal cavity when necessary can help remove excessive secretions.

3. Viral cold: Infections caused by rhinoviruses, coronaviruses, and other viruses trigger acute inflammation in the nasal passages, irritating the nasal mucosa to secrete clear mucus. Symptoms may include sore throat, cough, and low-grade fever, with the illness typically lasting 7-10 days. Patients should rest adequately, ensure sufficient sleep, and follow medical advice to take medications such as compound paracetamol and amantadine capsules, Ganmaoling granules, or ribavirin granules to alleviate symptoms, inhibit viral replication, and promote recovery from the cold.

4. Allergic rhinitis combined with a cold: Individuals with allergic rhinitis experience increased nasal mucosal sensitivity during a cold. The dual stimulation of allergy and inflammation leads to increased clear nasal discharge, often accompanied by frequent sneezing and nasal itching, with symptoms worsening upon allergen exposure. Avoid allergen contact, wear a mask when outdoors, and follow medical advice to take antiallergic medications such as cetirizine hydrochloride tablets, loratadine syrup, or mometasone furoate nasal spray to reduce nasal mucosal reactions and decrease clear nasal discharge.

5. Bacterial rhinitis: Secondary bacterial infection following a cold exacerbates nasal inflammation. Initially presenting as clear nasal discharge, it may progress to purulent mucus as the condition develops, accompanied by worsening nasal congestion, headache, and visibly congested mucosa upon nasal examination. Patients should maintain nasal hygiene, follow medical advice to use anti-infective medications such as amoxicillin capsules, cefaclor capsules, or levofloxacin hydrochloride ear drops to control inflammation and reduce secretions.

During a common cold, it is important to stay warm to avoid worsening symptoms due to cold exposure. Maintain a light diet and consume more fruits rich in vitamin C to boost immunity. Ensure good indoor air circulation and avoid dry environments; using a humidifier to maintain appropriate humidity levels can reduce nasal mucosal irritation and promote recovery from the cold while decreasing nasal discharge.

View All

What to eat for faster recovery from a cold caused by wind-cold?

For colds caused by wind-cold, it is generally recommended to consume ginger, scallion whites, perilla leaf, brown sugar, and warm porridge, which can help relieve symptoms and promote recovery. Ginger: Ginger is warm in nature and helps induce sweating to release exterior pathogens, while also warming the middle jiao and relieving nausea. During a wind-cold type cold, ginger can be sliced and boiled in water or consumed with brown sugar. This promotes sweating to dispel cold, helping to alleviate symptoms such as chills, nasal congestion, and clear runny nose.

View Full Answer

Is it okay to take Kugan Granules and Levofloxacin Hydrochloride Capsules for a sore throat due to a cold?

Ke Gan Granules can relieve symptoms of the common cold such as sore throat and cough, while Levofloxacin Hydrochloride Capsules are effective against susceptible bacteria. If a secondary bacterial infection develops during the later stages of a cold—manifesting as pus in the throat, yellow sputum, persistent fever—and bacterial infection is confirmed by examination, and if there is no drug allergy and liver and kidney functions are normal, combination therapy may be appropriate to simultaneously alleviate symptoms and combat the infection.