The common cold and the flu are both respiratory illnesses, but are caused by different viruses. Most people feel worse with the flu and experience fever, chills, cough, sore throat, runny or stuffy nose, aches, headaches and fatigue. The flu can lead to serious health problems including pneumonia. Colds usually involve a runny or stuffy nose and generally do not lead to more serious health problems.
Colds and flu are spread primarily through coughing and sneezing, and may also be spread by touching contaminated surfaces. Both illnesses can be prevented by covering coughs and sneezes with a tissue or an elbow; washing hands frequently; refraining from touching your mouth, eyes and nose with unwashed hands; and trying to stay healthy. There is an annual vaccine that can help prevent the flu.
Many people with asthma or other lung problems also have nasal and sinus symptoms. Drainage from your nose and sinuses can make asthma worse, especially at night. A saltwater nasal wash, or nasal irrigation, can help reduce this.