Diseases Home > Symptoms of Influenza
While similar, symptoms of influenza tend to be more severe and last longer than symptoms of a cold. Fever, chills, dry cough, and sore throat are the most common signs and symptoms. You can spread the disease to others before your symptoms appear and for another 3 to 4 days after your symptoms appear.
It's easy to confuse a common cold with the symptoms of influenza (also known as the flu). Cold symptoms are usually milder and don't last as long as influenza symptoms. If you become infected with the influenza virus, you will usually feel symptoms 1 to 4 days later. It is important to note that you can spread the disease to others before your influenza symptoms appear and for another 3 to 4 days after they appear.
These common influenza symptoms start quickly and can include:
Typically, the fever will begin to decline on the second or third day of the illness.
Although nausea, vomiting, and diarrhea can accompany influenza symptoms, especially in children, gastrointestinal symptoms rarely occur. The illness that people call "stomach flu" is not influenza.
Complications related to symptoms of influenza in adults can occur if they develop a bacterial infection, which can cause pneumonia in already weakened lungs. However, the flu virus alone can also cause pneumonia. Complications due to influenza usually appear after you start to feel better. After a brief period of improvement, you may suddenly get symptoms, such as:
- High fever
- Shaking chills
- Chest pain with each breath
- Coughing that produces thick, yellow-green mucus.
Pneumonia can be a serious and sometimes life-threatening condition. If you have any of these symptoms, you should contact your healthcare provider immediately to get the appropriate treatment.