Colds and flu

Colds and flu are both respiratory illnesses with similar symptoms, but they are caused by different viruses.³

The common cold is a viral infection that attacks your upper respiratory tract (your nose and throat).⁴ Symptoms usually include coughing and sneezing, a sore throat and a runny or snotty nose.⁴

Influenza (flu) is a viral infection that attacks your upper and lower respiratory system (your nose, throat and lungs).⁵ Flu normally starts off feeling like a regular cold and then gets worse with symptoms like fever and chills, muscle aches and fatigue.⁵ Flu also has a higher risk of more serious complications like pneumonia and bronchitis.^3,5

Find out more about the symptoms of colds and flu and how to treat them.

Inflammation and infection

Inflammation (swelling) in your nasal passages and sinuses may also sometimes be a symptom of allergies.⁶ If inflammation goes untreated, an infection can start to develop in your sinues or nasal passages, causing a build-up of thick mucus and making the problem worse.^6,7

Congestion

Congestion in the nasal passages and/or sinuses can be described as a blocked, heavy or restricted feeling.⁸ It can be caused by conditions that can inflame your sinuses and make your body produce extra mucus.^8,9 Symptoms of excess mucus production include swelling, pressure and pain in the nose and sinuses.⁹

Learn more about managing nasal and sinus congestion.