Hot flashes and nausea are most commonly caused by hormonal imbalances in the body, most notably, by sex hormones. For women, a decrease in estrogen is often to blame, whereas in men, testosterone deficiency can create the problem. Sometimes, the symptoms occur for reasons not related to those hormones at all.
Flu Symptoms. Symptoms of the flu generally begin more suddenly than those of a cold and they are more severe. Flu symptoms include a fever, sore throat, congestion, cough, muscle aches, general soreness, moderate to severe fatigue and headache.
While the common cold and influenza share many clinical features, acute cold symptoms typically appear gradually over one to two days, whereas influenza symptoms (high fever, severe muscle aches, dry cough, severe headache) are typically more severe and abrupt in onset, often developing within hours.