The most commonly misdiagnosed conditions in medicine are cold and flu. These two conditions are sometimes wrongly used in place of one another to refer to any kind of mild infection of the upper respiratory tract. However, there are many differences between these two conditions. Before we go on to discussing the differences between influenza and common cold, let us see in brief what exactly are they. Common Cold As the name suggests, it is practically the most common infectious disease to affect any individual. This is a contagious viral infection that affects the upper respiratory tract. It is caused due to rhinovirus or coronavirus. The common symptoms of this condition include constant sore throat, runny nose, and at times, a headache. A sore throat is usually the main symptom that helps to differentiate between flu and cold. These symptoms generally resolve spontaneously within a few days, though they may last for up to three weeks as well. Influenza Influenza, or flu as it is commonly called, is an infectious disease that is caused due to RNA viruses that belong to the family Orthomyxoviridae. This virus infects birds and mammals. Though, this condition affects the entire respiratory tract, it leads to systemic symptoms like fever, chills, and body ache as well. This disease is far more serious when compared to the common cold. One of the main factors that helps to differentiate between these two conditions is the fact that the systemic symptoms can become quite serious if not dealt in time. It may lead to complications like nausea, diarrhea, gastroenteritis, etc. It might also lead to lung infections like pneumonia, which is a fatal complication. Difference

Symptom	Cold	Flu
Onset of symptoms	The symptoms generally appear gradually.	The symptoms usually appear within three to six hours of contracting the virus.
Sneezing	One of the most typical symptoms of a common cold is constant sneezing.	Sneezing is rare in people who have flu.
Fever	Fever is very rare in case of a common cold.	Fever is present in case of a flu.
Body ache	This symptom is not observed in people who have only a cold.	It is observed in people affected by this condition and may be quite severe in some cases.
Stuffy nose and sore throat	It is commonly seen in people affected by common cold.	It is relatively uncommon in people affected by flu.
Chills	Cold is not accompanied by chills.	Chills and fever are common in flu, as it is seen in more than half the patients.
Headache	People experiencing a cold may or may not have a headache. If a person has a build up in the sinus cavities, then he may experience a sinus headache.	Headaches are relatively common in flu.
Tiredness	Very rare in a cold.	In case of flu, the person may experience excessive tiredness and weakness. This is often exacerbated due to the body pain.
Cough	If a person has a cough along with a cold, then the cough will generally be productive, that is, if it is a wet cough.	Persistent dry cough is quite common in flu.
Chest congestion	Chest congestion and chest discomfort is relatively rare in a cold, and if present, it is mild to moderate in nature.	Chest pain and discomfort is quite common in people affected by a flu. The flu often causes a lot of congestion and chest discomfort.
Complications	Sinus congestion, headache, and earache.	The complications of influenza include various lung diseases like pneumonia.

When it comes swine flu versus regular cold flu symptoms, the symptoms of swine flu will be much more serious and quicker in onset when compared to common cold. However, in the end, precaution is always better than cure, hence, if you are experiencing symptoms that make you suspect influenza, then it is best to visit a doctor and get the condition diagnosed and treated at the earliest.