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.
Cold symptoms typically begin with a sore throat that may be mild or severe. After a day or two, the sore throat improves and nasal symptoms, such as congestion or a runny nose, appear. Nasal secretions begin as a thin and watery discharge, then develop into a thicker and darker discharge several days into the illness.
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.