Similar symptoms of cold and flu can make it hard to tell the difference. In either case, the illness usually lasts for one to three weeks. The symptoms of a common cold develop slower than flu in two to three days. Flu symptoms start suddenly and take only a few hours to fully develop. Flu is usually more serious because it worsens underlying chronic illnesses. Both cold and flu can be caused by a virus, so antibiotics will not help.
Fever
Flu may trigger a fever of over 102° F lasting up to four days. Usually, the fever with cold rises up to 102° F and will not get any higher.
Runny and Stuffy Nose
Common cold is more often associated with runny, stuffy nose with discharge and sneezing. Flu virus may also cause stuffy nose with much less discharge.
Muscle Aches
The flu virus may cause severe muscle aches all over the body early on after getting infected, especially legs, back and head. The common cold may cause mild aches, which are restricted in the head and upper body.
Fatigue
A cold patient may feel tired and worn down but is usually able to function almost normally. The flu can cause severe fatigue and exhaustion from days to few weeks, sweeping patients off their feet.
Cough
Dry cough is a symptom of a flu, and may become severe. Cough with the common cold virus is milder and produces phlegm.
Headache
Severe headache is more often a symptom of the flu virus. A common cold may cause a mild headache.
Nausea
Flu very often causes loss of appetite. Nausea and vomiting are more likely a symptom of a flu virus than a common cold.
Chills and Sweating
Chills, sweating and feeling cold are very common with the flu virus. If a cold virus triggers a fever, feeling cold is very likely.
Sore Throat
Flu may be associated with sore throat, but sore and scratchy throat are more characteristic with cold virus.
Warnings
There is no cure for common cold or flu, but it is important to see a doctor if symptoms get severe or linger for more than two to three weeks. Flu can cause more severe and even life-threatening complications like bacterial pneumonia and bronchitis. In severe cases, prescribed antiviral medication may relieve symptoms. Other severe symptoms are extreme irritability, nonresponsiveness, high fever above 103° F or fever lasting more than three days, and dehydration. Sinus congestion, sinus infections and ear infections are possible complications of a common cold. A course of antibiotics may be prescribed for prevention or treatment of opportunistic bacterial infections following a cold or flu.
